# Scored a Nice 16" Parabolic Reflector. HID or Short Arc? Test Beamshots w/ HID.



## JP Labs

*Scored a Nice 16" Parabolic Reflector. HID or Short Arc? Test Beamshots w/ HID.*

I have been truly impressed with the variety and performance of the searchlight builds here, so I have been watching for a quality reflector, cheap. As you all probably already know, this is not easy! Well, I finally found one that seems pretty great for less than $100, shipped. I am excited. Now, I need to decide what to do with it. I would like the community's help to select a lamp/power supply, and with various other build questions that will come up. I hope this thread will be interesting to you, as well.​ 







*Goals: 
I want to be able to put an obvious spot on clouds as first priority, and maximize visibility of the beam as second priority. I want to minimize spill. I live a mile from a small city with all its outdoor lighting, so I am working with a fairly bright nighttime sky. *
--
*EDIT *to add a constraint on power, per post 18:*

Constraint:  
Run from car 12V battery power for at least 5 minutes. Run from idling car power for as long as I want to. Big, clamp on inverter or 12V direct are both OK.*

--

I would love to have 20k lumens or more! But the 8000 or so (?) lumens from a '100W' HID is very accessible and easy. Would fewer lumens with a smaller source like a projector short arc be better for my goals?

While I have studied many of your beautiful builds and learned what I can, this seems to be a unique project. I am leaning towards salvaging a lamp and ballast from a DLP projector. But not sure.

My budget for a lamp & ballast is hopefully <$250. I could go higher for significantly better value. Portability is not terribly important, as this will go on some kind of tripod/turret mount, so anything heavy can go on the stand. 12V is preferred over mains power, but I do have an inverter. Modified wave. 750/1500W. Vector VEC043.

From what I have learned here, I think the relatively large reflector means it can collimate a proportionally larger light source, so maximum surface brightness might not be so important for my goals. Maybe HID will be better for this, and short arc overkill that unnecessarily compromises beam power. I know it's a tradeoff, but for my goals, what do you think is the optimal lamp technology? 

Here's what I know about the reflector:






From the markings, I think maybe it is an electroformed reflector from Phoenix, or similar. Can you help me ID it?



P/N P60-08 
16" Diameter 
Focal length is about 2". You can see this in the pics - bulb is focused. 
Rhodium plated from the RH marking. 
Very smooth image, not a spun reflector, I think. 
About 1mm thick at edge. Can measure if helpful 
Outer surface looks to me like the ED reflectors. But I think they are Nickel, and a magnet will stick to mine. Are ED reflectors magnetic? 
 
As soon as it arrived, 2 days ago, I had to play. I started on an adapter to house a spare 35W HID to test it. I found that an old Air Conditioning R/D I had was a perfect OD to fit the reflector ID, so I cut it down on my Smithy and pressed my lamp into it:




This fits nicely, and I use 2 o-rings to retain it while allowing adjust-ability.









Note the AA battery for scale:




The lamp is from a Harbor Freight Off Road HID that was on sale a while ago at 2 for $49. I think the outer glass tube is a UV filter. Is that correct? 

Here are a couple of beamshots.

From about 100' away, not quite dark out yet:




From about 4' off-axis:




Zoomed in on cloud. Small spot already, so I am very encouraged! The spot is deformed here. If I hold the light by its base, the spot is round. But here, it is set into my sunroof opening, which slightly distorts the shape. Very sensitive! 




This light throws very much better than the 9" Autozone spotlight I modded with the matching HID. And I think it looks rather well collimated. So, already it makes HID seem like it might have a small enough source to work well. 

What do you think? What lamps should I consider for the final build? What would you do?

I'm off to try to source a tempered cover lens, and then to the shop to start fabricating a mounting system.


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## BVH

*Re: Scored a Nice 16" Parabolic Reflector. HID or Short Arc? Test Beamshots w/ HID.*

Just a quick reply on reflector Identification. Might be an Optiforms P60 here:

//www.optiforms.com/parabolic.htm

Find the P60 and go right to the VIEW button for different configs of the P60 and find the "-08" unit to get your specs.

RH means: Electro deposited Bright Rhodium. That's a nice reflector!


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## FRITZHID

*Re: Scored a Nice 16" Parabolic Reflector. HID or Short Arc? Test Beamshots w/ HID.*

Very nice! A short arc would look awesome in that. Nice laser like beam. Now for you to find a lens to protect it!

Sent from my SAMSUNG-SM-G730A using Candlepowerforums mobile app


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## JP Labs

*Re: Scored a Nice 16" Parabolic Reflector. HID or Short Arc? Test Beamshots w/ HID.*

BVH - Thanks for that link! The dimensions match as closely as I can measure. I think you ID'd it. :twothumbs So, it's a 2.35" focal length and it catches an 85 degree band of light from the source. 

Fritz - Thanks for the suggestion about short arc.

I did find a lens. The local lighting shop had an extra 17" Tempered Glass lens lying around. When I answered the inevitable 'what model light' with a brief description of the project, the guy thought that was neat, so he gave it to me. I threw $5 in the coffee fund.

I also started on the frame and mounting system. I'll get some pics up soon.


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## JP Labs

*Re: Scored a Nice 16" Parabolic Reflector. HID or Short Arc? Test Beamshots w/ HID.*

Ok, pics. Here is the frame on the lens. Note this lens is just a flat piece of glass to protect it, not part of the optics. The lens has a gasket and a galvanized steel surround, with 3 spring clips. These clip over feet of the frame. Frame is 4130 tubing, overkill but on hand. Joining is silicon bronze, TIG brazed. I didn't clean the steel very meticulously, so the joints are a bit dirty, but it will be abrasive blasted and painted.





Reflector mounted. Center ring of frame is clamped under the threaded nut that retains the center tube to the reflector, with an o-ring under it, so there is no load to deform the shape. There is a gap to the glass, about 1/2", so I can have forced air cooling.




This is the horizontal orientation in which it will be mounted. Center leg up. Hopefully this will provide some protection for the reflector if something ever falls on it. 




Detail of reflector mounting:




The 2 center tubes that the mounting ring are attached to will also support two pivots for mounting the whole thing to a yoke. That yoke will mount on a tripod. 




Pivots will go here, at the end of the 'V'. This is near the balance point. The glass is heavy.


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## BVH

*Re: Scored a Nice 16" Parabolic Reflector. HID or Short Arc? Test Beamshots w/ HID.*

Looks like excellent quality construction! You're moving right along. In my humble opinion, you really should go with a 500 to 1,000 Watt Short Arc system. Of course, the problem will be finding a compatible power supply and lamp system for a price within your budget. The power supply will probably be somewhat heavy also at that power range. I don't know if your modified Sine Wave inverter will cause a problem with a Short Arc PS or not. I bought a used Oriel universal 400 - 1000 Watt, Xenon and Mercury-Xenon PS with its' associated lamp housing off Ebay for around $1,000 a while back. The lamp housing contains the ignitor so only low (relatively) voltage cables run between the PS and ignitor. You could mount the ignitor to your framework so that the final high KV run is very short. Search Ebay using oriel arc lamp or oriel arc supply or other similar combos. If you use a Mercury Xenon lamp and PS, then you will not suffer loss of Lumens versus regular Automotive HID. Lumens per Watt are much higher with Mercury Xenon vrs Xenon. If you go with something in the range of 200 to 500 Watts, the used supplies on Ebay are quite a bit cheaper than one that supplies up to 1000 Watts. For cooling, search Vaneaxial on Ebay for high-CFM, small size fans. I can do some research on the vaneaxial unit in my Spectrolab Starburst 500 Watt light to see what the CFM is if you decide to go with something of that power range. I don't see an open space around the lamp in its' mount for cooling air to blow over? (assuming you go with a short arc system) This will be fun to watch. Post lots of pics!


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## Bill Idaho

*Re: Scored a Nice 16" Parabolic Reflector. HID or Short Arc? Test Beamshots w/ HID.*

Yeah, I'm sittinhg her with a bag of popcorn, awaiting the outcome. I have a vested interest in this!!! My VSS-3 guts are looking compatible to this.


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## JP Labs

*Re: Scored a Nice 16" Parabolic Reflector. HID or Short Arc? Test Beamshots w/ HID.*

Thanks for the encouragement, guys!! 

So, another (highly regarded!) vote for short arc, as big as possible. Re-reading some info from BVH, Ra, and Get-Lit last night, I now better understand that Mercury short arc is more efficient than Xenon, needs very precise adjustable mounting, and about the UV and explosion hazards. Nice guidance. 

BVH, you are taunting me with the potential of a better lamp. Good! I will try to execute something in that direction, instead of a simple HID kit set up. *Decision made:thumbsup:.* Now, it is all about what I can find, and what is a good value. I will look into the Oriel lamps and universal power supplies you suggested. They are not out of the question. I will try to build this light to satisfy me the first time. (I can not ever allow myself to think about my relative with a movie theater, and my welder power supply).

It is funny how, the more I put into a project in build hours, the more easily I can justify nice parts. In my twisted logic, each hour of fab time is worth about $50 of my precious free time. So, that is a $500 frame I spent most of yesterday working on, with materials.:thinking: Seems a similar value is now justified for the heart of the beast. But, probably not 4 figures cost.

Good suggestion to consider a configuration which will allow me to keep the HV leads short.

I am more seriously considering the highest powered range of used video projectors for donors. These are rated up to 8000 ANSI Lumens OTF, so the lamps must provide more than that. But that approach is a gamble, relying on my ability to get the power supply to work once extracted. I think I could figure it out. I think there is a very significant benefit to using a projector. They have smart controls. I would try to keep the control system intact, using the temp sensor, fans, fan control, and airflow sensor to manage cooling and provide automatic shut down if something fails. Since a burst bulb could probably destroy my precious reflector, I think this is significant. 

BVH, about your cooling suggestions, great info. I am a Thermal Systems Engineer by trade, so I have some grasp of what is needed, but never worked with lamps like this, and experienced suggestions are best, so thank you. I'll look into this more.

You are correct, there is currently no air path in my lamp mount. But it is hollow, and can easily be opened up on the end around the lamp to guide airflow over the lamp. A concentric aluminum tube could be welded on to better direct air at the lamp, or to mount a Pyrex tube that surrounds the lamp if necessary. While the test lamp (HID with bigger arc, so not as sensitive) is nicely centered because the current mount is a lathed part, I do not think it is good enough for a short arc source. The fit of my lamp mount in the reflector allows some wiggle, maybe 1 mm at the arc. If I go the short arc route, I think I would make a better lamp mount, with 3 axis adjustment. Maybe I can reuse this one, and add 'tilting screws' to turn the mechanical slop into a feature. I also have ideas about easily adjustable focal length.

I do have a couple of gasoline generators (easily carried 900W and heavy 4500W) which could be used if the modified sine inverter is insufficient. I think single-RPM analog generators are sine wave by nature. But the inverter is preferred, so I can run it from the car more easily for parties.

--
Possible lamp option:

I sent an email to my various friends asking for leads on big projectors. I learned of a working used commercial projector that uses a *330W Ushio NSHA Mercury Short Arc Lamp*, which I might be able to buy. Service manual with schematics, too. I couldn't find specs for the lamp itself, so don't know lamp lumens. Anybody know?

Is it reasonable to assume that this type of lamp can run vertical, without dying in a very short time, if well cooled?

I am thinking of offering a couple hundred bucks for this projector, but maybe I should offer more. While that lamp is on the low end of what BVH recommends, it seems to be at the high end for single-lamp A/V projector power. It might be a very good value for short arc lumens/dollar, compared to buying a lab power supply and lamp separately. Maybe that used projector is worth a few hundred dollars to me in light power. 

The most reasonable used Oriel power supply I saw today with 500W capacity is $550 (Oriel 68811 on the big auction site) without a lamp, so the projector is probably worth a few hundred easily, by comparison, if it is suitable. 1KW Oriels are going for 3x that much.

--

Bill, I am VERY jealous of your VSS-3!! I wish I had such nice hardware to work with. In fact, your old thread about acquiring it was one inspiration for my 2 year online search for anything with a good reflector. It showed such things are sometimes attainable. But VSS-3 bring big money, and I never found one that seemed reachable, so I am building from scratch. I hope that the info shared here will help you in your quest to find a suitable lamp system to finally bring it to life! It is very hard to find a 'plug and play' recommendation, and such lamps need careful operation, thus my tendency to start with a salvaged projector system so everything plays nice, electrically and thermally. On the other hand, there are some really well documented builds here that either of us could duplicate, if time and funds allow. But they tend to be seriously high end stuff. CPF attracts the big dogs of the DIY lighting world, doesn't it? Nice to have them to learn from.

--

I'm off to work on the mounting hardware. Should have a few more pics later today.


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## BVH

*Re: Scored a Nice 16" Parabolic Reflector. HID or Short Arc? Test Beamshots w/ HID.*

When I machine lamp adapters to fit over a lamp base, I shoot for about .0005" clearance and end up somewhere between .0005" and .001". I assume you will build some sort of 3 to 4-leg spider to provide support for and an adjustment mechanism for the front of the lamp you settle on. As long as the front is supported, that up-to .001" adapter clearance in the back will not result in any significant focusing issues. As far as upward shinning of the light (which we all want to do), most SA searchlights I have and have seen place the Anode (the bigger, more massive electrode) in the rear of the reflector so that when the light is pointed down from an aircraft, boat, what-have-you, the brunt of the arc flame which naturally rises is against it. Reverse that scenairo and there is some amount of tendency for some of the effect of the flame heat to be directed back towards the small, thin Cathode which does some damage and results in less lamp life. That's the theoretical and now to the real-world for us enthusiasts. I've talked a few times with my contacts at Advanced Radiation Corp (my obsolete lamp supplier) about this issue and I have specifically asked them about pointing my Spectrolab lights (they make the OEM lamps) up as much as 60 degrees above the horizontal and the answer is pretty much what I just wrote - You will technically shorten the life of the lamp but if you're starting with a 1000 hour lamp, you might still get 300 - 500 hours of good life out of it if it's life is spent pointing up. They do caution to not run it for excessively long times when only pointing up. They say pointing horizontal won't shorten life by much. With Mercury Xenon, the amount of cooling is more critical as you may have read in Getlit's Nightsword thread. Too much and you won't get full Lumens output.

Are you after a Laser beam or a flood monster or something in-between? 

If you end up with a 500 Watt system (closer to 650 Watts total) then you're not going to want to run it off your car battery for more than a minute or so. 650/12=54 Amps of current. That's why I ended up making a 9-Cell, 100 Ah LiFeP04 portable battery. With that battery, I can run the 1600 Watt (1800 Total) NightSun for three, 20 minute sessions before needing to re-charge it. I also bought a 1500 Watt, Full Sine Wave, 24VDC input (22V - 33V input range) inverter so that I can power some of the 120VAC SA power supplies out in the field from the same battery. I need if for my TrakkaBeam 800 Watt PS and my M134 minigun light PS. The battery system is also great because there is no generator noise. You should hold out for a 500 Watt system. That is a great compromise between the 150-300 Watt systems and the 1000 Watt systems.


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## JP Labs

*Re: Scored a Nice 16" Parabolic Reflector. HID or Short Arc? Test Beamshots w/ HID.*

I got the yoke built yesterday, and stuck it on a temporary tripod. Then I got invited to a buddies bonfire at his defunct 10 acre apple orchard in the country, where it is darker, so I just HAD to stop working and go play. I'll get a couple pics up soon, and more tonight or tomorrow.

His place was once overgrown, and now it is carved up into a maze like network of grassy trails. Several of us regularly race around these park-like trails on mopeds and small (250cc or less ) ATVs and motorcycles. It is easy to get lost or disoriented. I ran the 35W HID test bulb for about 3 hours vertical as a beacon, and it was great. 

--

Wow BVH, you are really helping me, here. I truly appreciate your interest and suggestions. I feel like a little kid who showed up at a park, and an NFL pro dropped by to teach me how to toss a football. 



BVH said:


> When I machine lamp adapters to fit over a lamp base, I shoot for about .0005" clearance and end up somewhere between .0005" and .001".
> 
> I assume you will build some sort of 3 to 4-leg spider to provide support for and an adjustment mechanism for the front of the lamp you settle on.
> *
> I was not planning a spider. But I suppose a large lamp would require this for support. If I use a lamp with electrodes on both ends, I can do this.
> *​
> As long as the front is supported, that up-to .001" adapter clearance in the back will not result in any significant focusing issues. As far as upward shinning of the light (which we all want to do), most SA searchlights I have and have seen place the Anode (the bigger, more massive electrode) in the rear of the reflector so that when the light is pointed down from an aircraft, boat, what-have-you, the brunt of the arc flame which naturally rises is against it. Reverse that scenairo and there is some amount of tendency for some of the effect of the flame heat to be directed back towards the small, thin Cathode which does some damage and results in less lamp life.
> 
> *Can the lamp simply be installed with the large electrode, the Anode I believe, on the top? It seems that would help with the heat issue. Also, since the hot spot in the arc is formed at the Anode/big electrode, I think this would direct more light rearward towards the reflector. That is the way I envisioned setting it up.*
> 
> That's the theoretical and now to the real-world for us enthusiasts. I've talked a few times with my contacts at Advanced Radiation Corp (my obsolete lamp supplier) about this issue and I have specifically asked them about pointing my Spectrolab lights (they make the OEM lamps) up as much as 60 degrees above the horizontal and the answer is pretty much what I just wrote - You will technically shorten the life of the lamp but if you're starting with a 1000 hour lamp, you might still get 300 - 500 hours of good life out of it if it's life is spent pointing up. They do caution to not run it for excessively long times when only pointing up. *
> After last night's fun, I really want to be able to run this completely vertical for extended times, as a beacon. With a quiet generator or idling car, I could do this. 30 degrees off vertical (the 60 you mention) could work but I would make trade-offs to be able to achieve vertical. If that is completely out of the question with short arc lamps, I could keep an HID lamp configured as a simple drop-in for beacon mode, with correspondingly lower power so it can run silently from a car for long times.*​​​​
> They say pointing horizontal won't shorten life by much. With Mercury Xenon, the amount of cooling is more critical as you may have read in Getlit's Nightsword thread. Too much and you won't get full Lumens output.
> 
> *Yes, because the vapor pressure of the gasses inside will not climb high enough if the lamp is too cold, as I understood.*​
> Are you after a Laser beam or a flood monster or something in-between?
> 
> *Something in between. I don't really have any 'safe' targets more than a mile away, except maybe clouds above, so reach beyond that seems un-needed. From the discussions about 'Beam Power' (Get-Lit if I recall correctly), I think that is what I want to maximize. Highest beam power, with ability to put a nice spot at 1 mile, including on clouds above. *​
> If you end up with a 500 Watt system (closer to 650 Watts total) then you're not going to want to run it off your car battery for more than a minute or so. 650/12=54 Amps of current. That's why I ended up making a 9-Cell, 100 Ah LiFeP04 portable battery. With that battery, I can run the 1600 Watt (1800 Total) NightSun for three, 20 minute sessions before needing to re-charge it. I also bought a 1500 Watt, Full Sine Wave, 24VDC input (22V - 33V input range) inverter so that I can power some of the 120VAC SA power supplies out in the field from the same battery. I need if for my TrakkaBeam 800 Watt PS and my M134 minigun light PS. The battery system is also great because there is no generator noise. You should hold out for a 500 Watt system. That is a great compromise between the 150-300 Watt systems and the 1000 Watt systems.
> 
> *I have a 1920 hit or miss engine which needs a job. It's a 2 1/2 HP Stover. It makes nice noises, and could spin an alternator. This may wind up configured as an optional power source for parties. But I don't think it would have the oomph to power a 500W lamp. With a larger lamp, it could extend the runtime of a battery significantly, though. Generator or idling car would be acceptable to run big lamps.
> 
> The large battery packs intrigue me. I also want to build an electric bicycle in the next year or so. At that point, I would have a 15 AH 48V or so LiPo pack to share. But that would be a later mod, not designed into the initial light's features.
> *​


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## JP Labs

*Re: Scored a Nice 16" Parabolic Reflector. HID or Short Arc? Test Beamshots w/ HID.*

OK, here are a few quick pics as promised. I am short on time, but will add a few more later.

Simple fixture to align the mounting pivots, which are simply bolts:




Pivots installed in yoke:





Temporary setup. Tripod is NOT robust enough - only temporary. Need a solid, wide one for safety! I purposely made the yoke extra tall, to leave room for electronics if needed. Can shorten easily if not needed. 




Another beamshot. Again, this is the test lamp, just a 35W CHEAP HID. Seems to be AC, not DC.




The spot, from about 100 yards *(EDIT - only 65 or 74 yards per Google Map, not sure which tree it was on the map)*:


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## BVH

*Re: Scored a Nice 16" Parabolic Reflector. HID or Short Arc? Test Beamshots w/ HID.*

Absolutely the lamp can be installed Anode up. The brightest light source is actually right off the tip of the Cathode and it gets dimmer as the arc progresses towards the Anode. Technically, the brightest light source would be pointing directly out the front instead of back to the reflector. But again, in real world use, it is probably not going to matter at all for your use. Getlit could give you a much better answer than I can.

The only SA I've seen without a spider is the marine ACR 150 and 300 Watt lights. They're mounted on boats/ships so very little vibration/shock potential. But if you were to remove the lamp for transport and reinstall it on-site and then not move the structure once it is running and hot, I think you'd be fine.


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## JP Labs

*Re: Scored a Nice 16" Parabolic Reflector. HID or Short Arc? Test Beamshots w/ HID.*

Couple more. 





The furthest I viewed from was about 296 yards, and the beam was BARELY visible when aimed straight up.
The furthest target (tree) I illuminated was about 435 yards, and the spot was still strong and bright. No pic, since it is on a neighboring property and I just touched it for a moment.

This one is from about 130 yards away. Below shot's camera settings.
F2.8
1/2 second
ISO1600
Focal Length 4 mm
Equivalent 35 mm Focal Length 25 mm






I am realizing that I don't have any suitable (read: certainty that I won't blind or annoy anybody) long distance objects to illuminate that are not on roads, or straight up. The one mile away tree I can hit from home is along a road, so not for regular use. This is why I think my goal should be beam power, more than throw. I am not in an aircraft pattern, nor are the places I camp. And when we camp in the woods, it can be hard for others to find us. A beacon would be fun for such times.


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## FRITZHID

*Re: Scored a Nice 16" Parabolic Reflector. HID or Short Arc? Test Beamshots w/ HID.*

Have you considered a manual focusing mechanism? Shouldn't take much movement to go from full flood to tight laser like spot.

Sent from my SAMSUNG-SM-G730A using Candlepowerforums mobile app


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## JP Labs

*Re: Scored a Nice 16" Parabolic Reflector. HID or Short Arc? Test Beamshots w/ HID.*



FRITZHID said:


> Have you considered a manual focusing mechanism? Shouldn't take much movement to go from full flood to tight laser like spot.
> 
> Sent from my SAMSUNG-SM-G730A using Candlepowerforums mobile app



I was only going to have a screw and spring to set up the bulb, and to tweak it a little. Flood to spot would be a nice feature to add. I would want it to be mechanical, no focus motor. A lever or twist grip, maybe. Not sure how to do that.

Any ideas?


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## BVH

*Re: Scored a Nice 16" Parabolic Reflector. HID or Short Arc? Test Beamshots w/ HID.*

All you need to do is create a lamp holder/adapter movement mechanism that will give you roughly .250" of "Z" axis movement forward of the focal point to get flood. How does your lamp holder attach to the reflector? How can you make it slide forward and rearward? Secure it with a large ring nut? Can't tell from the first pics but it looks like you already have the capability. Is that a big ring nut I see and threads on the lamp holder?

EDIT: I re-read post and I see you're using two O-rings to hold the focus position (Z axis) of the lamp holder. Are the 6 holes in the reflector hub ring threaded? Maybe drill and tap two opposing holes in the side of the lamp holder and make some type of "L" brackets with slots that will bolt to the hub ring and sides of the LH. Slot the L brackets and use the bolts to lock it down in any focus position you want.


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## JP Labs

*Re: Scored a Nice 16" Parabolic Reflector. HID or Short Arc? Test Beamshots w/ HID.*

More Discussion About Goals:

Playing with the light and seeing what I can do with it has been 'illuminating' for me. My goals are adapting. 

My own suburban home is not the best testing ground. Too close to the road. 

I set it up again briefly last night, at another buddy's house in the country, for a ~5 minute run just to demonstrate. I am a lot more comfortable doing that, than using it in my own suburban yard on a fairly busy 2 lane road. Every car that drives by can tell where its coming from. Its awfully nice to be able to pull it out and plug in to the car. And to have a silent power source for short runs (Suburban's Optima Yellow Top in this case). 

Certainly, grid power is ok for testing and home use, but my best opportunities to use this have been away from wall sockets at parties hosted by my friends. If I needed a heavy, noisy generator to run it, I could do that, but I don't think I would use the light very much. My light might become a 'once a year toy'. 

I want to be welcomed, even encouraged, to bring this to social events without annoying the host and guests. My generator is annoying.

While it would certainly be more fun for me to build the biggest, most powerful setup I can, I have realized that I want 'grab and go' capability. Toss it in the car (well, Suburban) and bring it with me on short notice. It should not be a requirement to hook up the trailer and load my heavy 4500W generator. (It is too heavy for me to set in back of truck).

While my functional goal for the light hasn't really changed, I think this means I need to add a constraint. I think I should limit power draw to a level that an inverter will support so I can run it from battery clamps for a few minutes, or with a 180A alternator, idling, for an hour or more.

Having an HID lamp I can install for 'economy mode' would have achieved this for the smaller lamp, but I think most of my usage will be off grid, and I don't want to have to use the weaker lamp all the time. While I wrote above about it not being a problem to power a big lamp, I have realized that doing so would restrict my use quite a lot, and that generator noise would make me a lot more conspicuous and annoying to anybody nearby. I want to be as quiet as possible. So, my 'big lamp' choice should enable this.


*Additional constraint:* (added to original post 'Goals' statement for clarity).
*Capability to run from clamp-on style inverter, or direct 12V, from alternator power.*

I think this means an A/V projector is my upper limit for lamp power, not a 1kW monster.

Thoughts?


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## JP Labs

*Re: Scored a Nice 16" Parabolic Reflector. HID or Short Arc? Test Beamshots w/ HID.*



BVH said:


> All you need to do is create a lamp holder/adapter movement mechanism that will give you roughly .250" of "Z" axis movement forward of the focal point to get flood.
> 
> *1/4 inch should be do-able with the current mount. I think I read that de-focusing should always be done by moving the lamp rearward, so as not to cause the focal point to hit the lamp and overheat it. Glad you corrected my about that - defocus FORWARD from focal point, OK.*
> 
> How does your lamp holder attach to the reflector?
> 
> *It is a sliding fit, no threads or positive location, yet.*
> 
> How can you make it slide forward and rearward? Secure it with a large ring nut? Can't tell from the first pics but it looks like you already have the capability. Is that a big ring nut I see and threads on the lamp holder?
> 
> EDIT: I re-read post and I see you're using two O-rings to hold the focus position (Z axis) of the lamp holder. Are the 6 holes in the reflector hub ring threaded? Maybe drill and tap two opposing holes in the side of the lamp holder and make some type of "L" brackets with slots that will bolt to the hub ring and sides of the LH. Slot the L brackets and use the bolts to lock it down in any focus position you want.
> 
> *I used that ring to clamp my bracket to the REFLECTOR *_(edit correction, originally wrote LAMP)_*, so it is not available for focusing. But, I could extend the frame rearward and put a plate behind the lamp, with one bolt in the center. Then I could use springs to pull the lamp against the bolt. Turning the bolt would push against the springs and push the lamp holder forward.
> 
> *


----------



## JP Labs

*Re: Scored a Nice 16" Parabolic Reflector. HID or Short Arc? Test Beamshots w/ HID.*

There is a problem with the way I built the glass cover into the light. The gap between my reflector and cover lens was added for airflow, but it causes 2 problems. Bugs get in, and light spill hits those who look towards the light, even if pointed almost straight away from the observers, because light bounces off the inside surface of the cover glass. I don't think this is safe. This is why I had the light set up to be above head level, so far. I will add a black baffle which blocks this, so all you see is the beam. It will probably just be a strip of aluminum flashing formed into a ring. positioned to cover this gap.


----------



## JP Labs

*Re: Scored a Nice 16" Parabolic Reflector. HID or Short Arc? Test Beamshots w/ HID.*

*Why defocus by moving lamp forward of focal point instead of rearward?*

I thought about this more, and the way I am picturing the light path, if I move the lamp forward of the focal point for flood, then the angles to the reflector become more acute (smaller), and the light will cross over itself. It seems that this would possibly result in a hot spot of focused light landing on the bulb. Defocusing by moving the lamp rearward would make the light bounce angles get bigger, so the light would diverge into a spot pattern without crossing over itself and making a hot spot. 

I don't claim to actually understand this, and may not be correct, above. But I have seen comments that support each technique for de-focusing. Can we discuss this more? I would like to understand.


----------



## JP Labs

*Re: Scored a Nice 16" Parabolic Reflector. HID or Short Arc? Test Beamshots w/ HID.*

I'm going to try to start breaking my questions into shorter posts to make them easier to read and reply to. I realize that some of my posts are on the long side, and probably not easy to follow.

Here's a question specifically about visibility of the beam:

*Does a smaller arc size reduce visibility of the beam for a given bulb lumen level?* 

If so, might spending more on a 330W high pressure short arc mercury lamp actually hurt beam visibility, as compared to using an automotive HID running at 80W or so? I don't think so, but would like to make sure it's worth the extra effort and $$ to do the short arc, for my restated goals and power limit. 

I know this partially repeats something we discussed above, but I would like to better understand this trade-off. I need to make a firm offer on the projector soon if I want it. Can't decide what it's worth to me in performance terms.

Further complicating the decision is that I still haven't been able to find a bulb lumens rating for the 330W Ushio NSHA Mercury Short Arc Lamp contained in that projector. I think it will be far more than from an HID, according to BVH's comments about efficiency, above. 

*Can anybody confirm this with high confidence, specifically comparing that bulb vs. a "100W" HID bulb?*


----------



## JP Labs

*Re: Scored a Nice 16" Parabolic Reflector. HID or Short Arc? Test Beamshots w/ HID.*

One more post before I go. I found pictures of an 'equivalent' bulb to the Ushio in the projector. I think I could cut most of the reflector off with my wet tile saw, but it looks like it might be very difficult to remount after that. No good flange to put in a base. 





BVH's suggested lab supply and lamp options in the < 500W range would cost a bit more, but would not have this problem. I am realizing that is a pretty darn good suggestion. Maybe I need to give up on the projector idea.

Any suggestions on how I might handle adapting a lamp like the one pictured above?


----------



## BVH

*Re: Scored a Nice 16" Parabolic Reflector. HID or Short Arc? Test Beamshots w/ HID.*

My short answer is that getlit is the real go-to member for your beam visibility questions. From what I remember, beam visibility has more to do with the Focal Length of the reflector - short vrs med vrs long FL and I think the long focal lengths provided a better beam visibility and a more uniform beam cross section brightness.

I have found that when I lump questions together in long posts, many do not get answered. I have started to number my questions 1-x and have had more complete responses. 

I wish getlit was on more. He could set you straight quickly.

I should have asked if the projector lamp was a reflectorized unit. I've never figured out a way to use them, and I have purchased and then sold a few. Much easier dealing with brass or stainless cylindrical bases on conventionl SA lamps.

I don't think your posts are too long.

More editing: IIRC automotive HID and M.V. SA may be close to the same efficiency/Lumens per Watt. SA is around 35 to 40 LPW whereas HID and M.V. SA might be around 100 LPW. Seems to me that all other factors being equal, a shorter gap will result in a higher surface brightness (better throw) but lower overall Lumens.


----------



## JP Labs

*Re: Scored a Nice 16" Parabolic Reflector. HID or Short Arc? Test Beamshots w/ HID.*

Rats, I wrote up quite a response but lost it to 'Token Expired', twice. Then I noticed the 'Restore autosaved content' button at the bottom when the blank response window showed up on the refreshed page. I never saw that before, and wish I had known about it one refresh ago. 

So, in case others don't know about it:

If the forum loses your reply due to an error, look for the *'Restore autosaved content'* button! You might get all of your work back! 

-----

Maybe this is elementary to regular users....on to my post:

Thanks, BVH, that is helpful. I appreciate your hanging out in this thread with me, and your info! 

I know I have been asking very specific questions that are hard to answer, but I'm interested in all aspects of making and using a light like this. If you guys have related thoughts, don't worry if they are a little off topic. I'm interested. 

I don't have very much experience with optics or electronics, so that's what I am asking about. I am no professional machinist, but I do like to build stuff, and would be happy to answer questions about that.

On that note, I will explain a little more about how I made that frame in the next post.


----------



## BVH

*Re: Scored a Nice 16" Parabolic Reflector. HID or Short Arc? Test Beamshots w/ HID.*

If I'm going to write a somewhat long post, I do a "preview" after each paragraph or so and maybe even copy that paragraph to the clipboard. I can usually get to the last saved screen by using the BACK button if I have done the "preview" thing.


----------



## JP Labs

*Re: Scored a Nice 16" Parabolic Reflector. HID or Short Arc? Test Beamshots w/ HID.*

Ok, here's that frame again. 





While I used a TIG welder and a lathe to make this, it could be done with much simpler tools. A $50 MAPP gas torch, a drill press, and a file would go a long way. A Dremel, belt sander, or die grinder would be nice.

I didn't 'design' this, in that it was not dimensioned and laid out as a drawing, or anything like that. I visualized what I wanted, built the first part, checked the fit, and did that again and again until it was done. 

First I made the mounting ring (#1). I did not make this from scratch. I started with a steel ring intended to be a pipe joint, which I got from the local scrap yard for $2. I just looked for something that had an ID as close to what I needed as possible, but smaller. I ended up having to remove about 0.100" radius material from the ID. I used a lathe, but a grinder would work fine. It doesn't even need to be precise, really. It gets clamped under a threaded ring on the reflector assembly that is quite wide. Hole needs to be big enough, but sloppy is OK.

Once this ring was installed on the reflector, I needed to start shaping the frame.

I started by setting my glass cover on a blanket, flat, on my bench. I put (3) 1/2" nuts on the glass cover to set my air gap, and then set the reflector on these, face down. I centered the reflector by putting my index fingers on opposite sides of the inside of the glass cover's edge band, and feeling it. This works surprisingly well, and is plenty close for the task. Easily within 1/16". This put the reflector just where I wanted it in final configuration, and made the ring (#1) the foundation of the frame layout. Everything else starts there.

I built off this, directly. I hardly measured anything. I would hold a piece of metal up to the reflector, put a mark on it, bend it, and go compare it again. If it fit, I would tape it in place, with a clothespin or chunk of cardboard under it as a spacer. Coat hanger wire or pipe cleaners would be good to use to develop these shapes if you haven't done this before, so you won't have to bend and unbend the steel tubing to get it right. Then use the hanger wire as a template when you bend the steel.

I simply bent the tubing in a vice, with a pipe stuck over the end to give me leverage on the larger ones (3/8 OD tube). For the smaller ones (1/4 OD solid), I would bend by hand and then bang with a hammer to get a sharper bend. I needed two of each part. I'd make the first, then use it as a template to make the second. 

I would leave each piece about 1/4" longer than I thought it needed to be! That let me adjust by trimming to make up for the inevitable errors and asymmetry that would show up when I brazed it, since I did not have a sturdy fixture. First timers might want to leave 1/2". Welds and braze joints warp when they cool. It also gave me a little room to grind an angle on the end of one piece, to match the side of the one it would be brazed onto.

I made the main braces (#2, brazed to the ring) first. 
I bent the tube sections to rough shape, two identical pieces. I set the ring on a flat surface, set the 2 bent rods along side it, and brazed only the tips of the tubes together. Then I tweaked the shape to make it sit flat with equal heights on both ends, and brazed it onto the ring. 

Now, welding would be tricky here. The tubing is thin, the ring is thick. Tubing is Chrome Moly Steel, ring is stainless. It is possible to weld the two parts together, but not good practice, and the tube would tend to melt away before the ring was hot enough. 

Brazing does not care so much about different materials and thicknesses. You don't have to get things as hot, and you don't have to melt the parts you are attaching. You can attach combinations of mild steel, brass, stainless, copper, nickel, cast iron, titanium, and more. 

With a TIG welder, I use Silicon Bronze rods. This material is available for MIG welders, too, but I have not used it that way. Oxy Acetlyne brazing is an option, if you have that gear.

The easiest brazing I have ever done is Silver brazing. It is strong, but the melting temperature is within the range of a MAPP Gas torch. A regular propane torch will not work well, get one for MAPP gas, or dual fuel. A decent Bernz-o-matic is only about $60. Chinese ones are 1/4 that much. You will need a small roll of Silver Braze wire from your local welding store, and some flux. And some kind of decent eye protection with tint. Not necessarily welding goggles, it is not arc-weld bright. But a little too bright for naked eyes. I have done it with sunglasses, not recommended though.

I next made 2x of (#3) and brazed these in place. I did one side first, only on one end, the top! I can't final braze at the bottom with the lens in place, because the heat would wreck it. More on that in a minute. 

I held a tube in place, eyeballed the angle I would need on the end, reshaped it on the grinder, and repeated until it made good contact at one edge, and was within 1/16 or so everyplace else. That is close enough for this application, the braze will fill it. Strong enough for what it is. 

Finally, I did the shorter legs in the back. Not numbered in the pic above.

This left me with a spider shaped frame that would stand flat on the bench, but each leg was a slightly different length and angle. Bend, grind, recheck until all are sitting close to the bench.

For the attachment tabs (#4) I made a cardboard part first for fit, then hammered a scrap of stainless in the vise to match. 3 total. 

Here is where my technique would need to be modified a bit to adapt to using a MAPP gas torch. With TIG, I can pump a bunch of heat in, fast! To put it in appropriate language here, it is a 20 kW Argon arc lamp with no enclosure, and an arc length of about 4 MM. :sick2:

This let me quickly put a drop of braze on a joint to 'tack' it, wait a few seconds, then blast compressed air onto the part before it could melt the rubber gasket in the cover lens. Once they were all tacked like this, I could pull the lens out, and finish the brazing. (fast cooling a braze joint will weaken it! But these are only tacks, and once final brazed, will be fine.

With a MAPP torch, you would need to figure out how to hold the attachment tabs in place without using the lens, during brazing. All else is the same. If the MAPP torch can't heat a big part quite enough, you can put it on a barbeque grille to get a head start. Or invite a friend and use two - simple propane for assist, even.

Oh yeah, one last thing. Don't use stainless unless you have to! It is a pain to drill and cut. Mild steel is much nicer to work with. I only used stainless for the ring, because that is what I found in the scrap pile with suitable dimensions.


----------



## JP Labs

*Re: Scored a Nice 16" Parabolic Reflector. HID or Short Arc? Test Beamshots w/ HID.*

Busy working week. I spent a little time playing with light baffling, but nothing worthy of pictures yet.

I did not buy that big AV projector I mentioned above. Asking price turned out to be way too high. One digit too many.

---

So, now I am looking at other lamp options again. I will try to summarize the various categories I am considering, with some key points I think I have learned here, and in my related searches:

*Laboratory mercury arc lamps* like the Oriels BVH pointed me towards. Power level varies, but 100W is most common. Kind of hard to find, need to match possibly untested components to have a chance of reasonable cost, and still expensive. Probably a $500+ set up at 100W. 
*XBO short arc mercury lamps* in the form of microscope illuminators. Easier to find in running condition, cheaper that either option 1 or 3. Maybe $300 for either 100W or 200W. This is probably the most expensive option I should consider.... EDIT: Life only 200 hours for XBO lamps?! 
*Motion Picture-type 'HMI Fresnel Studio Lights'* that could be cannibalized. Entry cost for this type would be the highest, because there are no low powered options. Middle cost option for the power rating of the lamp. Highest lumen output in the ~500W maximum range I think I can run off a vehicle, I think. About $650 but you get a lot of lumens! 
*Run of the mill DLP projector.* Certainly the cheapest option, maybe $50 working, shipped. Pain to remove bulb from reflector, and then mount it precisely. Could afford to try more than once. Cheapest mercury short arc source. 
*100W rated HID* is my baseline option, but I am hoping for shorter arc length and higher output. $60. 

So, there is quite a spectrum of prices, configuration, and outputs spanning my searches, now. 
---

I learned of *HMI lamps*, used in option 3 above, in the 'Superlights Shootout' thread, from this post. They sound pretty good.

Complete HMI studio lights can be bought NEW, shipped from China unfortunately, for about $650 in 575W power. Housing, lamp, ballast, ignitor, lens, ready to use. 1200W is only a little more cost. Either would be tough for me to power from a vehicle, but 575W is probably possible if idling with all 12V stuff turned off. These entire studio spot lights cost less than buying a separate HMI lamp, ignitor, and ballast, it seems. The HMI bulbs used in them are single-ended mounting style, and output 49,000 lumens @ 575W!! But I don't know arc length or luminance, and didn't find the info easily. I need to find out more about these lamps! Way above my desired cost, but new, ready to run, and 49k Lumens? What am I missing? :thinking: Probably, the fact that buying it from China may not go well. They do offer a 14 day money back guarantee, with free return shipping. But, it takes more than 14 days to get here, so how can that work? I think the cost is too high, and risk too high, for me to chose this. It would be very nice to find just the lamp and ballast/ignitor for a fraction of the total light's cost, though!

One thing I like about this 'pseudo single-ended' lamp configuration is that it looks easier to cool the electrodes adequately, without overcooling the lamp's gas mix. As BVH alluded above, on a double-ended lamp you need to cool the far electrode without overcooling the bulb. Tricky.

I don't think I can link to auctions, but if you search for "Pro As arri HMI Fresnel" on a large auction site, you will see them, including pics of the lamp configuration. 

---

The *microscope illuminators* seem more accessible than laboratory short arc lamps like the Oriels, both in price, and in being able to buy a complete, running set up. I am not sure if I could cool the ends adequately, without overcooling the gas mixture, in axial mounting configuration.

I haven't found a combination of 'Tested, good parts' to set up even a 200W Oriel mercury arc laboratory lamp with ignitor & power supply for much less than $800, yet. The ignitors seem to be the expensive/scarce component. I will try to keep watching for a deal. I am impatient to find my final light source, though!

The microscope illuminators could be bought or put together for less than half that cost, maybe $300 or a bit more, using tested working components. So that might possibly be an option. 

HBO 100/2 and HBO 200/4 seem to be the most common ones available. These two similar-sounding lamp options are very different, in terms of intensity and output. 


Classically referred to by the registered trademark as *HBO* lamps (*H* for *Hg* or mercury; *B* is the symbol for luminance; *O* for unforced cooling)
I think I like the HBO 200W better, due to output, but the arc gap is about 9 times bigger than the 100W!! 
Lumen output is 4-5x as much for HBO200 vs HBO 100. But only 1/2 the lumens/watt of the HMI lamps, and 1/5 the output, for 1/2 the price. 
Luminance is DRASTICALLY better for the HBO 100W vs 200W. 
EDIT: HBO lamp does not require forced cooling, but lamp life is only 200 hours and 100 starts?! This article gives a pretty thorough and interesting description of HBO lamp technology http://zeiss-campus.magnet.fsu.edu/articles/lightsources/mercuryarc.html 

Which to maximize for my build, luminance, or lumens? I think I need to find the best compromise of both. But where is the balance?


*Question: 

With my larger reflector, which of these HBO lamps do you guys think would be more suitable for generating a highly visible beam, as opposed to max throw?*



.
*Lamp
**HBO100/2
**HBO200/4
*Nominal luminous flux2200 lm*9500 *lmLuminance*170000 *cd/cm²33000 cd/cm²Luminous intensity260 cd*950 *cdArc Length*0.25 *mm2.2 mm










Please feel free to share your thoughts.


----------



## JP Labs

*Re: Scored a Nice 16" Parabolic Reflector. HID or Short Arc? Test Beamshots w/ HID.*

I found an interesting, 1967 NASA report about remote sensing illuminators, including a bunch of Short Arc Lamp info. I didn't realize lamps like the XBO and HBO short arcs had been around that long. I have only skimmed the report, but this is where I found the arc length data (p27/166), for example: Link to NASA Report PDF


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## JP Labs

*Re: Scored a Nice 16" Parabolic Reflector. HID or Short Arc? Test Beamshots w/ HID.*

Here's a useful description of mounting and thermal considerations for the HBO lamps, from the above linked article:

_As discussed above, mercury arc lamps contain a precisely measured amount of metallic mercury within the envelope, and they are filled with argon or xenon, which acts as a starter gas as the mercury vaporizes. When the lamps are cold, small droplets of mercury can often be observed on the inside walls and the gas pressure inside the envelope is lower than the ambient pressure of one atmosphere. Once the lamp is ignited, the mercury vaporizes over the course of a 5 to 10 minute transition phase. During this period, the lamp is operated at higher than normal current, requiring the anode to be positioned at the bottom of the lamp to ensure proper vaporization of the mercury. For this reason, the ferrule sockets in a mercury lamphouse have different diameters (one smaller than the other) to enable correct positioning of the lamp, which itself has a larger ferrule on the anode end of the tube. Thus, mercury arc lamps are positioned vertically within the lamphouse with the anode pointing toward the bottom and the cathode pointing upward. Operating a mercury lamp at an angle exceeding 30° from the vertical position deflects the arc toward the quartz envelope resulting in uneven heating and premature darkening of the bulb. Several mercury lamp designs incorporate a reflective coating on part of the envelope to speed the vaporization transition phase and to improve thermal distribution. Because the envelope temperature influences the internal mercury pressure to a significant degree, mercury arc lamps are sensitive to airflow over the bulb and this aspect must be carefully controlled by the lamphouse._


----------



## JP Labs

*Re: Scored a Nice 16" Parabolic Reflector. HID or Short Arc? Test Beamshots w/ HID.*

More on Projector lamps:

Many DLP projectors use UHP lamps, with a nice 1mm arc length. Very high luminosity. So, I investigated UHP lamps more deeply today, to see what I might get myself into. It is becoming evident to me that they have critical cooling requirements which would be too difficult for me to reliably duplicate with a lamp extracted from a projector. The entire quartz envelope must be kept between 1190k and 1400k. Risk of bursting lamp and ruining my reflector during testing would be high, unless I err on the side of overcooling, in which case output will be weak, and the lamp will turn black due to recrystallization on the cooler parts of the quartz. 

Another point for BVH; I am beginning to see why he never pursued projector lamps, and gently tried to steer me away from them. HBO lamps and HIDs are less intense, but do not have this same level of risk. 

ma sha1 made UHP work in his Mega Blaster and Moon Blaster, so it can be done:thumbsup:. But the photos from those thread are gone, and I don't have any idea how he cooled the lamp. I don't dare attempt it myself without more info. I think it is unlikely I will hit the proper operating temperatures, and it is not really possible to measure. 

If anybody has experience running UHP out of a projector, I would love to hear how they cooled it!

The more I learn, the more difficult it is to pick a better lamp than HID! It is hard to beat 100w HID with similar output in a smaller arc, without spending a LOT more. I can't see a way, yet.

More info about UHP thermal design here, for anybody interested, p.16: http://koti.kapsi.fi/jahonen/Electronics/Stuff/UHP_Lamp.pdf


----------



## JP Labs

*Re: Scored a Nice 16" Parabolic Reflector. HID or Short Arc? Test Beamshots w/ HID.*

Been reading more build threads.....saw a post from get-lit hinting that Philips MSR Gold lamps might be worth looking at. So, I did. Well, it turns out they are universal position, with special crimps which make them more tolerant of running hot. They are HID MH type lamps with ~5mm arc length. 300W delivers ~22k Lumens. But the only listed ballast on Philips' site is an obscure German one. 

Does anybody know if the universal digital MH ballasts can strike and run these?


----------



## BVH

*Re: Scored a Nice 16" Parabolic Reflector. HID or Short Arc? Test Beamshots w/ HID.*

I'm still enjoying your posts and wish I could contribute more but I've never found a way to buy reasonably priced lamp and ballast sets anywhere so I've never set out to build my own light.


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## JP Labs

*Re: Scored a Nice 16" Parabolic Reflector. HID or Short Arc? Test Beamshots w/ HID.*

Thanks for letting me know the posts are still at least somewhat interesting. They have deteriorated more towards indecisive ramblings, I know. I think I will just stumble around the web until my learning curve intersects my 'remaining patience' curve. At that point, I will impulsively buy something and try it. I am spending too many hours reading, and not enough building. Stuck. 

I'll get back to pictures and action, eventually!


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## JP Labs

*Re: Scored a Nice 16" Parabolic Reflector. HID or Short Arc? Test Beamshots w/ HID.*

deleted post.


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## BVH

*Re: Scored a Nice 16" Parabolic Reflector. HID or Short Arc? Test Beamshots w/ HID.*

found a working Oriel 50 - 200 power supply for less than $200 on Ebay. It's for Xenon and Mercury Xenon

ww.ebay.com/itm/ORIEL-68805-UPS-UNIVERSAL-ARC-LAMP-POWER-SUPPLY-40-200W-PSU-REGULATED-/291236077736?pt=LH_DefaultDomain_0&hash=item43cf05e0a8

This operates the same as my 450-1000 (which is really 350 to 1200 Watt) You preset the Watts or Amps you want by pushing in the small middle black button and using the black rotary knob to set your level on the meter. Release the preset button and you're free to start the lamp by pushing the smaller start button over on the left. Once running, the supply is infinitely adjustable by simply turning the larger black rotary knob. It's a very nice older linear style PS.

"Short Arc Lamp" search on Ebay and then sort by lowest price first yields lots of sub $100, even some sub $50, new, 200 Watt Mercury/Xenon lamps. Many by Advanced Radiation Corp (my obsolete lamp supplier) Be sure to investigate to make sure they are not UV-specific lamps.


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## JP Labs

*Re: Scored a Nice 16" Parabolic Reflector. HID or Short Arc? Test Beamshots w/ HID.*

Thanks BVH! Every time I get tired of talking to myself here, you chime in and remind me I am not alone in this. 

I had seen a few PS like the one you posted. It does look like a good supply, perfect really. However, *I think that power supply requires an external ignitor, doesn't it? *

I thought it prudent to find an ignitor first, since that seems to be the rarest and most expensive component. That is the part I have been having a hard time finding. Do you have an ignitor, too, or do you DIY that part? I do have Neon transformers and furnace ignitions that can make an arc, but am a little hesitant to play with the lethal HV and inject it into the power supply, for fear of killing it or me. 

_Note to future readers of this thread: I know ebay links are not great for documenting thread content because they expire. It is not helpful to read an old thread and not be able to see the details of posted auctions that are gone, so I have noted the prices and general descriptions below to try to keep some utility in the info. _
--

Here's a similar one that went for $140 yesterday: _Oriel 68700 Analog Display 100W/200W Xe Hg Selection Arc Lamp Supply Unit_​ww.ebay.com/itm/111453399366?_trksid=p2055119.m1438.l2649&ssPageName=STRK%3AMEBIDX%3AIT
​ --

Here's the least expensive Oriel ignitor I am currently watching. $452, too steep for me I think, but does come with a lamp housing that would have some utility for mounting parts etc. A lamp housing alone went for about $50 last week, so I don't think that is a large part of the value here: _Oriel Arc Lamp & Arc Lamp Ignitor 660055 SVGA 68705 working_​ww.ebay.com/itm/310448805023?_trksid=p2055119.m1438.l2649&ssPageName=STRK%3AMEBIDX%3AIT​ 
--

This is the cheapest complete running setup I have found, an HBO200 microscope illuminator. Did not sell for $400. Non-adjustable PS. OLD! _Carl Zeiss Binocular Microscope Lamp Housing HBO 200/4 Base + Power Supply_​ww.ebay.com/itm/271590115028?_trksid=p2055119.m1438.l2649&ssPageName=STRK%3AMEBIDX%3AIT​


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## JP Labs

*Re: Scored a Nice 16" Parabolic Reflector. HID or Short Arc? Test Beamshots w/ HID.*

I have been reading all I can find about the Philips MSR-SA lamps. These are Metal Halide HID Short Arc lamps. Documentation says they 'are best on electronic ballasts but will work on magnetic ballast with an ignitor'. That implies to me that perhaps a typical MH electronic ballast would work. Such a ballast can be had for about $100, if it would work. However, the MSR-SA lamps list 'up to max 20s starting duration' under ballast specs, and most of these MH ballasts only apply HV starting for a few seconds. So, not sure they would work. But I really like the universal operating position, the robust pinch design for high temp running (500C ends, 1000C envelope) and the fact that they are single ended (both electrodes on same end) but have a traditional axial arc orientation. I would like to run one in 400W power if I can. 30,000 Lumens, 3mm arc. Pretty sure these are intended for AC operation, not DC, so would not have sharpest illuminance profile, but a LOT better than the AC HID I am using as baseline for my project.

Here is the product spec sheet for the MSR SA lamps:
https://www.1000bulbs.com/pdf/Philips_MSR_SA_specsheet.pdf

EDIT: This is the brand recommended by Philips for ballasts for the MSR lamps (non-short arc versions are just called MSR, not MSR SA), but they do not seem to specify if MSR SA works on same ballasts. Schiederwerk. Even sounds expensive. I can't tell if these operate substantially differently from other MH electronic balasts (cheaper ones!).
http://www.schiederwerk.de/index.ph...-and-ignitors-led-drivers/electronic-ballasts

Here are two MSR 400 SA lamps for $125. New ones are about $120/ea or less from lamp stores. Not too bad, if they can use a cheap ballast:ww.ebay.com/itm/MSR-400-Sa-Bulb-Short-Arc-Phillips-Two-Of-Them-One-Price-/301213544681?pt=US_Stage_Lighting_Replacement_Bulbs_Lamps&hash=item4621b9f0e9​
Here's a 400W MH electronic ballast for $75:_400w HPS MH GROW LIGHT Digital ELECTRONIC Dimming Ballast DIMMABLE 400 W WATT_

ww.ebay.com/itm/400w-HPS-MH-GROW-LIGHT-Digital-ELECTRONIC-Dimming-Ballast-DIMMABLE-400-W-WATT-/380866780593?pt=US_Hydroponics&hash=item58ad6dddb1​


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## JP Labs

*Re: Scored a Nice 16" Parabolic Reflector. HID or Short Arc? Test Beamshots w/ HID.*

Too bad I am limiting my power to 500W or less for off grid running with car power. Or I could maybe be done with this search.

*Here is a possible deal for somebody who might be following this, thinking of a similar project...a 1200W Schiederwerk ballast for $200! 

*_*I cannot confirm this is an appropriate combination due to the lack of specific SA notes on the ballast, so that is still an open question.*_*

*The MSR SA Gold 1200W lamps are double ended, beautiful, and can be had for only about $130 new. Somebody can have 102,000 Lumens in a 7mm arc! 

--

Here's that lamp spec sheet: 
http://download.p4c.philips.com/l4b/9/928175305115_eu/928175305115_eu_pss_aenaa.pdf

--

Here is the ballast spec, listing MSR as appropriate, but again, not specifically the MSR SA:
http://www.schiederwerk.de/index.ph...arge-lamps/up-to-1200-watt/26-pvg-12-12-ac-sl
--



Here's the ballast:
*Schiederwerk PVG 12-12 AC SL Electronic Ballast, 115/230VAC, 47-63Hz, 1200W*

ww.ebay.com/itm/Schiederwerk-PVG-12-12-AC-SL-Electronic-Ballast-115-230VAC-47-63Hz-1200W-/331276943878?pt=LH_DefaultDomain_0&hash=item4d21a50206

-----------

Bill in Idaho, this might be nice for your project?


----------



## BVH

*Re: Scored a Nice 16" Parabolic Reflector. HID or Short Arc? Test Beamshots w/ HID.*

Too bad you're not closer. I just bought a most likely new and unused, old stock Oriel 69920 which is the newer switch mode 450-1000 Watt model of the Linear Supply model I have now. I went to use the Linear supply yesterday and did not remember that it must weigh 50-60 lbs which is not good for my weak back. I have a complete 450-1000 Watt lamp housing with ignitor and the OEM connection cables for the Linear unit. I am hoping that the ignitor will work with the new PS but the connection cable is different and the wiring pinout description is different. Where the old ignitor I have gets a 35khz pulse to activate it, the newer ballast (I don't have) says it gets a momentary ground. I know that does not necessarily make them different but I am not sure I know enough to test it out. I would think they would be the same. If not, I will be looking for a lamp housing with ignitor and as you say, they are expensive.

Long story short, I will probably sell the Linear and lamp housing with ignitor and they will work down to 350 Watts. But I don't look forward to shipping it. This heavy stuff is a pain to ship without damage. And you're limiting your power so this doesn't fit the bill anyway.

The linked ballast and some lamps do sound perfect for Bill of Idaho. Bill, are you listening.....? I just sent Bill a PM with a link to your post.


----------



## JP Labs

*Re: Scored a Nice 16" Parabolic Reflector. HID or Short Arc? Test Beamshots w/ HID.*

OK, finally, a little build progress worthy of pictures. I tried a 175W Mercury Vapor lamp in the light last night, but as expected, with a ~50mm arc length, it was terrible. No pics of that, imagine a 120degree wall of light. 

But, I worked more on the light baffle. Used my cellphone camera this time, sorry.

Started with a chunk of 18" Sonotube:




I peeled off the inside waxed paper layer and painted it flat black. This left a nice textured, non-glare surface. Wrapped it in aluminum flashing:




Front 3/4 view. This stops side and rear spill, allows airflow to exit around lens, and would block rain pretty well, too:




To mount it, I glued wood blocks to the tube ID such that they sit on the lens' metal surround ring, then glued Rare Earth magnets to the blocks. Sticks well. 

I was going to paint the aluminum black, too, but I am kind of liking the metal finish now. Maybe I just paint the frame black, but leave everything else raw. Or maybe I paint the whole thing in Olive Drab Green. Opinions?


----------



## BVH

*Re: Scored a Nice 16" Parabolic Reflector. HID or Short Arc? Test Beamshots w/ HID.*

Not a military light so no OD (in my military purest humble opinion) Flat or light gloss black is what aviation uses and would be nice. I like the raw alum look on the ring.


----------



## JP Labs

*Re: Scored a Nice 16" Parabolic Reflector. HID or Short Arc? Test Beamshots w/ HID.*

I have emailed an inquiry to Schiederwerk to confirm these ballasts work for the SA lamps, and ask if ignitors are needed, too. Also asked for a quote.

BVH, if your PS and ignitor/housing works down to 350W, maybe I could use it portable for 400W lamps, and have mains or generator powered fun at 1000W as a possible upgrade? Shipping is tough, yes. I don't know how the eBay sellers send these things across the country as cheaply as they do. Seems a pallet and freight handling might be needed to keep it intact. If you decide to sell these, keep me in mind.


----------



## JP Labs

*Re: Scored a Nice 16" Parabolic Reflector. HID or Short Arc? Test Beamshots w/ HID.*



BVH said:


> Not a military light so no OD (in my military purest humble opinion) Flat or light gloss black is what aviation uses and would be nice. I like the raw alum look on the ring.



I can respect the no OD colored 'poser' paint scheme opinion. Point noted. Unless I modeled the final configuration after a real Military searchlight, as a tribute of sorts, maybe. 1/3 scale Carbon Arc maybe? Perhaps I should go with a sci-fi death ray scheme? (Kidding. I think:thinking:.)


----------



## JP Labs

*Re: Scored a Nice 16" Parabolic Reflector. HID or Short Arc? Test Beamshots w/ HID.*

I just realized that ez78 used one of the Chinese electronic MH ballasts with a 7mm SA MH lamp in the '400W HID Thor' build. So, maybe running a 3mm SA MH could work. Encouraging. Maybe I will pick up a lamp and ballast to test. Roughly a $200 gamble, still undecided but currently is my leading plan. Part of the risk is running such a ballast from a modified wave type inverter.

Here is the Thor thread for those who may not be familiar:
http://www.candlepowerforums.com/vb/showthread.php?191645-400W-HID-Thor


----------



## JP Labs

*Re: Scored a Nice 16" Parabolic Reflector. HID or Short Arc? Test Beamshots w/ HID.*

This ridiculously long and detailed article about powering motion picture lighting seems to indicate that MH electronic ballasts can generally run from modified sine wave power (like my inverter), especially if the ballasts are power factor corrected. My auto voltage controlled generator should run them, too. 

http://www.screenlightandgrip.com/html/emailnewsletter_generators.html


----------



## JP Labs

*Re: Scored a Nice 16" Parabolic Reflector. HID or Short Arc? Test Beamshots w/ HID.*

Arrrgh, forgot to copy and lost a long post with a ton of ballast, inverter, and power correction info and questions to the Token Expired monster:hairpull:. Funny thing is it hadn't been very long, and the error repeated several times after refreshes. Oh well, I'm not fully recreating that post. 

Very briefly then:

I re-read the above Theatrical Lighting Power article (allow a couple of hours if you do this) and several other sources, including solar power forums. 

My tentative conclusions:


Electronic MH ballasts are highly reactive loads with leading current, low power factors. 
Power Factor Corrected (PFC) SMPS-based ballasts are better for AVC generators than non-PFC versions. 
For non PFC electronic MH ballasts, don't exceed about 1/3 of generator capacity. Will tend to overheat circuit, regardless. 
Either type should work (degrading this to might, not should) with modified wave inverters if they are lightly loaded. 
Don't try to run other devices on the circuit if you plug a non-PFC inverter into it. 


*Update:*

Here is what seems to be a respectable source, finally with a specific mention of HID lamps. Of course, they don't mention if the issues are with electronic, or magnetic ballasts. But I think the electronic ones are the ones likely to have issues, due to the bridge/capacitor input power supply that delivers DC for the actual inverter SMPS. This is the source of the distortion harmonics injected back into the power supply. From that source:

*Which devices will not function properly from a Modified Sine-wave Inverter?
*
Any device that uses a control circuitry that senses the phase (for voltage / speed control) or instantaneous zero voltage crossing (for timing control) will not work properly from a voltage that has a modified sine wave-form. Also, as the modified sine wave is a form of square wave, it is comprised of multiple sine waves of odd harmonics (multiples) of the fundamental frequency of the modified sine wave. For example, a 60 Hz. modified sine wave will consist of sine waves with odd harmonic frequencies of 3rd (180 Hz), 5th (300 Hz.), 7th (420 Hz.) and so on. The high frequency harmonic content in a modified sine wave produces enhanced radio interference, higher heating effect in motors / microwaves and produces overloading due to lowering of the impedance of low frequency filter capacitors / power factor improvement capacitors.
Some examples of devices that may not work properly with modified sine wave and may also get damaged are given below:



Laser printers, photocopiers, magneto-optical hard drives 
The built-in clocks in devices such as clock radios, alarm clocks, coffee makers, bread-makers, VCR, microwave ovens etc may not keep time correctly 
Output voltage control devices like dimmers, ceiling fan / motor speed control may not work properly (dimming / speed control may not function) 
Sewing machines with speed / microprocessor control 
Transformer-less capacitive input powered devices like (i) Razors, flashlights, night-lights, smoke detectors etc (ii) Re-chargers for battery packs used in hand power tools. _These may get damaged. Please check with the manufacturer of these types of devices for suitability_ 
Devices that use radio frequency signals carried by the AC distribution wiring 
Some new furnaces with microprocessor control / Oil burner primary controls 
*High intensity discharge (HID) lamps like Metal Halide lamps. These may get damaged. Please check with the manufacturer of these types of devices for suitability
* 
Some fluorescent lamps / light fixtures that have power factor correction capacitors. _The inverter may shut down indicating overload_ 

http://www.samlexamerica.com/support/faqs/faq02.aspx

Maybe it would be better to just use a magnetic ballast and ignitor, except I can't find one for these MSR SA lamps. 

Another option may be to modify the inverter to get DC out of it before it's 'inverting section' (another SMPS, I think). Feed that into the ballast, after its 'un-inverting section' (its SMPS). This would avoid the two troublesome middle steps, from DC to AC, and AC to DC again. Some other members have done this. But the voltage would need to match up.

Universal lab supply and ignitor sure is a nice solution if I can find a reasonable set.


----------



## JP Labs

*Re: Scored a Nice 16" Parabolic Reflector. HID or Short Arc? Test Beamshots w/ HID.*

OK, enough speculation; I'm sure many of you are getting sick of it, as am I. It is time to do something! :scowl:

*I just ordered TWO Philips MSR400 SA lamps.* One is new, one is open box and appears to be slightly used. The latter will be for initial testing. 

I also ordered one GY9.5 lamp holder, and a 40 mm vaneaxial PC fan with fairly high stall pressure, about 1" WP, to provide some lamp cooling flow through what will more or less be a 5mm concentric slot around the 40 mm diameter lamp base. 

Some of Philips' lamp specs show a minimum required cooling flow. Some do not. MSR SA lamps do NOT. So, I am thinking they may be able to operate un-cooled, but I will try a low level of cooling and see how that works. I can thermocouple the base (250C limit), but not the critical crimp area that destructs at 500C, or the envelope that destructs at 1000C, so it will be a guess at best. 

I did not buy a ballast, yet. I plan to wire up the base and bulb, grab my welding helmet, and take the lot to our local 'indoor garden center' to see if they are willing to try to sell me a MH ballast by attempting to fire my lamp with it. 

Parts should be here in about a week. 

*Aside from the danger of injury and fire, if the lamp overheats and bursts, is it likely to seriously damage my reflector surface?* I think so, but would love to hear otherwise, if anybody here has experienced such a lamp failure. 

If I actually get the thing running, I think I should stress test it for an hour or two inside something a bit stronger, with only the lamp mount and fan.:duck: Maybe in a section of 4" steel chimney tube with a small viewing opening at lamp level. Better to blow it up there, than in my reflector. 

If I use a pinhole in that tube, instead of a viewing hole, it might even project a viewable image of the arc onto paper for monitoring. SA HID Camera Obscura!


----------



## BVH

*Re: Scored a Nice 16" Parabolic Reflector. HID or Short Arc? Test Beamshots w/ HID.*

Years back I had a 150 Watt lamp let go. It left some major scratches from the big fragments and the entire reflector was heavily orange peeled from the small pieces of Quartz. Pretty much destroyed. I'd definitely test run it like you say, in something else. That is also the beauty of having the lamp housing. That's its' job - a test bed. Good luck with the testing!


----------



## JP Labs

*Re: Scored a Nice 16" Parabolic Reflector. HID or Short Arc? Test Beamshots w/ HID.*

OK, will do the testing for sure, then! Appreciate the input.


----------



## LightSward

*Re: Scored a Nice 16" Parabolic Reflector. HID or Short Arc? Test Beamshots w/ HID.*

If you had success with the 100 watt HID, then the 1,200 watt HMI would be decent. Did you look into Jenbo..? Work well on bad sine-wave inverters and poor voltage control circuits.. I've used them for a few years, bulb and ballast with ignitor is:

- http://www.bestbulbsdirect.com/Jenbo_1200W_Lamp_Ballast?osCsid=56be2ac470a1662449f14b7411c10653 ballast: $420.00 mailed regular US mail, fits in palm of hand...yes..1,200 watts HMI lightweight.

- http://www.bestbulbsdirect.com/Osram_Sylvania_HSR_1200-60_Replacement_Jenbo_NSK1200 bulb: $128.25, comes in regular US mail, lightweight.

I'm working on spinning my own reflectors out of steel and aluminum. Was using fiberglass molded on wax covered, spun concrete.





the Gorilla 36 inch totally homemade reflector using a Jenbo 1,200 watt HMI bulb and ballast.






*Mummy Mountain mile long beam shot*

Here you can see the top of Mummy Mountain a mile from this parking lot, lit by the Gorilla searchlight.


Another Day view:




*Mummy Mountain with Lodge, Church and Condo Complex*

Mummy Mountain with Lodge, Church and Condo Complex visible at base.


----------



## JP Labs

*Re: Scored a Nice 16" Parabolic Reflector. HID or Short Arc? Test Beamshots w/ HID.*

Thanks for checking in, Lightsward! 

I am quite familiar with your builds; I think I have read every page. That is some inspiring work, developing the form and layup techniques for reflector fabrication:thumbsup:. Your lights are awesome. When you need to build a crane to support your light hobby....:bow:.

I've made quite a few things with fiberglass and epoxy. I once cast an epoxy parabola on a record turntable. There are some small concentric ripples, but it worked well for the basic shape. I use it with a microphone. I tried with paraffin, first, but that rippled worse.

Thanks for the lamp tips. I will look into them, but I think the power level @ 1200W is more than I can run from a vehicle's 12V system.

EDIT: OK, that was fast and easy. Thanks a LOT for the info about these ballasts working well on dirty power!

Jenbo has a 400W ballast, a 400W double ended lamp, a 400W single ended lamp, and even a 400W short arc lamp which is listed as an alternate for the Philips MSR 400 SA. That Philips is the lamp I ordered. I expect the Jenbo ballasts should work with their own lamps, so the Jenbo 400W ballast should run lamp, too. Great info.

Ballast $300:http://www.bestbulbsdirect.com/Jenbo_400W_Lamp_Ballast

400W double ended lamp $104:http://400W double ended lamp:

400W short arc lamp, single ended $110:http://www.bestbulbsdirect.com/Philips_MSR_400-S_Replacement_Jenbo_NSK400


*Goals recap:*

I realize I was a little unclear, above, mentioning the 100W HID as a baseline. My testing so far has only been with a 35W HID. My default choice to replace that is a 100W HID. This 100W HID is the 'baseline' I am comparing other lamp options against. I am trying to pick a better lamp system which will significantly outperform that potential 100W HID for beam visibility, without disproportionately increasing the expense - at least not TOO badly. I'm aiming for a power level I can supply from an idling vehicle's 12V alternator. I think that should not be more than 500W lamp power, which might require up to 50A input @12V. Maybe a 575W.


----------



## BVH

*Re: Scored a Nice 16" Parabolic Reflector. HID or Short Arc? Test Beamshots w/ HID.*

Unless total ballast input power is listed, I'd be more conservative and use a factor of 125% to 130% of lamp power. Something closer to 625 Watts for a 500 Watt lamp. IIRC, my Spectrolab Starburst is even higher than that. Of course, I'm talking about Short Arc and not the HMI products - I am not knowledgeable about those.

Regarding the 100 HID...Do you have a specific ballast/lamp combo you are referencing or is that just a power level you're using as a base reference? If something specific, just be cautious of the claimed power to the lamp. So many of the automotive HID ballasts are producing far less than claimed lamp power. And so far, I have not been able to find an "automotive" HID lamp that would run at 100 Watts and live any where near 1,000 hours.


----------



## JP Labs

*Re: Scored a Nice 16" Parabolic Reflector. HID or Short Arc? Test Beamshots w/ HID.*

Understood about the 100W automotive HID, yes. Highest actual power I have seen reported is only 86W to the lamp, estimated Lumens 8000, (stolman, here). That's the type of kit I was considering. But, there is no stepping back to that for my final lamp, now!


----------



## LightSward

*Re: Scored a Nice 16" Parabolic Reflector. HID or Short Arc? Test Beamshots w/ HID.*



JP Labs said:


> Thanks for checking in, Lightsward!
> 
> I am quite familiar with your builds; I think I have read every page. That is some inspiring work, developing the form and layup techniques for reflector fabrication:thumbsup:. Your lights are awesome. When you need to build a crane to support your light hobby....:bow:.
> 
> I've made quite a few things with fiberglass and epoxy. I once cast an epoxy parabola on a record turntable. There are some small concentric ripples, but it worked well for the basic shape. I use it with a microphone. I tried with paraffin, first, but that rippled worse.
> 
> Thanks for the lamp tips. I will look into them, but I think the power level @ 1200W is more than I can run from a vehicle's 12V system.
> 
> EDIT: OK, that was fast and easy. Thanks a LOT for the info about these ballasts working well on dirty power!
> 
> Jenbo has a 400W ballast, a 400W double ended lamp, a 400W single ended lamp, and even a 400W short arc lamp which is listed as an alternate for the Philips MSR 400 SA. That Philips is the lamp I ordered. I expect the Jenbo ballasts should work with their own lamps, so the Jenbo 400W ballast should run lamp, too. Great info.
> 
> Ballast $300:http://www.bestbulbsdirect.com/Jenbo_400W_Lamp_Ballast
> 
> 400W double ended lamp $104:http://400W double ended lamp:
> 
> 400W short arc lamp, single ended $110:http://www.bestbulbsdirect.com/Philips_MSR_400-S_Replacement_Jenbo_NSK400
> 
> 
> *Goals recap:*
> 
> I realize I was a little unclear, above, mentioning the 100W HID as a baseline. My testing so far has only been with a 35W HID. My default choice to replace that is a 100W HID. This 100W HID is the 'baseline' I am comparing other lamp options against. I am trying to pick a better lamp system which will significantly outperform that potential 100W HID for beam visibility, without disproportionately increasing the expense - at least not TOO badly. I'm aiming for a power level I can supply from an idling vehicle's 12V alternator. I think that should not be more than 500W lamp power, which might require up to 50A input @12V. Maybe a 575W.



Excellent job so far. Like the welded frame work.

The *Jenbo* ballast ran all the other brand lamps, just fine..., some 25 years old from West Germany. I have an RV battery the size of automobile battery that will run the 1,200 watt for about ten minutes. I think your idea of using the 500 watt set up sounds reasonable, get 25 minutes run time, more if you leave the engine running...?

I'm just about ready to begin producing all metal parabolic reflectors in the 20-24 inch range. Have mostly built everything I need. I'm spending extra time on precision this time, more than ever, and have been amazed at my results so far.

Good work on this so far.:thumbsup:


----------



## Bill Idaho

*Re: Scored a Nice 16" Parabolic Reflector. HID or Short Arc? Test Beamshots w/ HID.*

Hang on guys, I ran out of popcorn.........................Tonight I'm going to run out and wipe the dust off the VSS-3 housing and parts, just in case this is my holy grail!


----------



## JP Labs

*Re: Scored a Nice 16" Parabolic Reflector. HID or Short Arc? Test Beamshots w/ HID.*



Bill said:


> Hang on guys, I ran out of popcorn.........................Tonight I'm going to run out and wipe the dust off the VSS-3 housing and parts, just in case this is my holy grail!



Bill, what did you think of the ballast above for your VSS? Appropriate at all?


----------



## Bill Idaho

*Re: Scored a Nice 16" Parabolic Reflector. HID or Short Arc? Test Beamshots w/ HID.*

It sounds better than anything else that has been mentioned. Changing the batteries in my flashlight pretty well taxes the limit of my electrical know-how, but if the right combo of ballast and bulb appear, as a certified machinist, I'll build whatever I need to. As long as it is a relatively simple plug things together and candlepower happens.....I'm in. 1000 watts would be about right. I believe the fan is still intact, although it might need to be wired, as most of the wiring was yanked out. 
A good poker player never shows his hand, but I'm good up to about $400-500. It sounds like I can stay well within that.


----------



## JP Labs

*Re: Scored a Nice 16" Parabolic Reflector. HID or Short Arc? Test Beamshots w/ HID.*

No lamps in the mail today. Was hoping.


As close as I can tell, the MSR 400 SA lamps I ordered are Short Arc Metal Halide lamps with Iodine as the halide. MSR is listed in cross references as Philips' alternative to Osram's HMI lamps, often cataloged under the same 'HMI Lamps' heading. The MSR short arc versions are listed in the same section. HMI lamps have a listed color temp of 5600k, same as the MSR 400 SA. 

I mention this because there isn't a lot if technical info to be found on MSR lamps, but there is quite a bit about MHI lamps. As far as I can tell, the two are technically equivalent. So I am applying what I can find about HMI lamps to my project, until or unless I find that is a poor assumption.

EDIT: Metal Halide lamps are AC lamps, as opposed to short arc Xenon or mercury lamps like the XBO and HBO - the latter operate on DC. AC inverters are thus required for the MH lamps. AC lamps have symmetrical electrodes, and 2 hot(ter) spots in the arc, one near each electrode. DC lamps have one small (cathode), and one large, (Anode) electrode. And one hot spot in the arc. The metal halides have effectively larger hot spots for a given power level, and also more lumens due to higher efficiency. 

Here are some links with more info about Metal Halide HID lamps. As a new user of the technology, I found them helpful. 

Here is one from Edison Tech Center which describes various types of these lamps, including HMI and Short Arc. (This whole site seems dedicated to explaining electrical technology of all kinds, with plenty on lighting):
The Metal Halide Lamp - How it works.

Next one is specific to short arc, and a bit more technical. Good section on hazards and safety precautions! Also some info on ballast requirements, and a brief section on short arc HMI lamps. Note that HMI lights are technically medium-arc not a 'true' short arc:

*Short Arc / Compact Source Lamps
*


This one is more specific yet - Wikipedia HMI entry


----------



## JP Labs

*Re: Scored a Nice 16" Parabolic Reflector. HID or Short Arc? Test Beamshots w/ HID.*

I know that the glass high bay lens that I put in front of my reflector will block most of the UV. Metal Halide lamps often have an outer glass envelope added specifically to block UV. MSR lamps do not have this envelope, and they do emit intense UV light. They NEED to have this UV reduced to a safe level. Is the glass safety lens enough? I expect so, since this is one of it's main purposes. But most or all intended lamps for high bay lights have that extra envelope. On the other hand, high bay lights shine on people all day long, day after day, so the permissible level would be correspondingly lower than for a short-use spotlight not aimed at people. 

Absorption depends upon thickness. Regular Soda Lime glass will reportedly stop all UVC, all UVB, and a majority of UVA. Polycarbonate is supposed to be much better at blocking UV. I could make a polycarbonate lens easily enough, but it would be less durable, and might melt.

Aside from getting a spectrometer, how can I assess the emitted UV level? One suggestion I read was to illuminate super white copy paper, and to look for fluorescence. Any blue glow indicates UV. So, using a fluorescent dye of some sort is one way. Phosphors won't work; they charge with visible light, too. Flourescence would give no indication of relative strength.

The best idea I can think of is to use photrochomic eyeglasses. I believe only UV will darken the tint. I could cover 1/2 of the light source with a thickness of polycarbonate, and place the glasses so that one lens receives full light, and one gets polycarbonate-filtered light. If only the lens on the unblocked side darkens, and it darkens a lot faster than it would in direct sunlight, then that would indicate significantly more UV than in sunlight. If both lenses darken equally fast, then they are sensitive to visible light, and the method won't work. The result is still subjective, because even with a stopwatch, it relies on judging how dark a tint has become. But at least it could provide some relative indication of UV intensity.

Does anybody have creative ideas for how to detect UV light amidst a lot of visible light, and gauge it's intensity?


----------



## BVH

*Re: Scored a Nice 16" Parabolic Reflector. HID or Short Arc? Test Beamshots w/ HID.*

I am a very safety conscious person. I worked for a public agency with an aggressive safety officer in the office next door. It was drilled into me for 34 years. So this may sound counter to my past experiences. You're never going to want to point the light at anyone so UV emissions should not really matter. And a momentary "hit" at some distance is not going to do any damage. Eye damage will occur before any burn damage. I remember someone foolishly putting their hand in front of (2" away from the window) Larry Black's VSS-3 at a get-together. He did, indeed get a slight burn on his hand. There is no UV spec given for the lamps you're considering? But again, not sure I'd concern myself assuming you're aggressive in safety procedures when using the light.


----------



## JP Labs

*Re: Scored a Nice 16" Parabolic Reflector. HID or Short Arc? Test Beamshots w/ HID.*



BVH said:


> I am a very safety conscious person. I worked for a public agency with an aggressive safety officer in the office next door. It was drilled into me for 34 years. So this may sound counter to my past experiences. You're never going to want to point the light at anyone so UV emissions should not really matter. And a momentary "hit" at some distance is not going to do any damage. Eye damage will occur before any burn damage. I remember someone foolishly putting their hand in front of (2" away from the window) Larry Black's VSS-3 at a get-together. He did, indeed get a slight burn on his hand. There is no UV spec given for the lamps you're considering? But again, not sure I'd concern myself assuming you're aggressive in safety procedures when using the light.



Thanks again for the good input. I agree about skin damage risk from UV being very low; I am more worried about eye damage from UV, though. Good operational safety - never pointing it at anybody - is certainly my intent. The accidental exposure risk is low simply because the probability of exposure is low, with responsible use. Any accidental exposure would likely be very brief, as well. 

What about eye damage from UV? Might that occur faster then one could sense pain from the visible light? * (EDIT: Answer = Yes, absolutely this can happen!)*

I would like to have a better understanding of the level of UV emitted. For example, is it foolish to illuminate a white wall from 50' for beamshots for 15 minutes, without eye protection? I really don't think so. But, I also don't want to use the 'Do my eyes hurt yet?' method any more than I have to!oo: 

I wear polycarbonate safety glasses even when testing the 35W HID in my shop, with indirect viewing. I know those lamps are supposed to be UV filtered, but I also know the factory HID lamps in my car have severely crazed/fogged the INSIDE of the plastic housing's front lenses over 100k miles, so there is still some UV. (Saab 92-x Aero if it matters). 

I realize this is a very challenging issue that we are unlikely to answer adequately. But in this particular forum, I think it merits some effort to try to understand. I feel that, if we are going to discuss building lights with a lamps that emits 'dangerous, intense UV radiation', then we should try to devote a respectable amount of effort to discussing safety aspects, too. If others hadn't done the same in their short arc threads, I might have read them without realizing there was a significant UV hazard to worry about. Also bulb explosion. Let me offer a sincere thanks to others who have included such warnings!

*<<< In case anybody has read this far and not figured it out, don't build something like this just because I am trying to - I barely know what I am doing! *

---


I've decided while writing this that I must improve the perimeter light baffle, so there is less rearward light 'splash' from light reflecting off the back surface of the lens in the narrow perimeter air gap. You can see how intense this small portion of reflected light looks even with the 35W HID, in the repeat-picture, below. The baffle is not installed, so the back-reflection is clearly visible. 

If 90% of visible light is transmitted through the glass (optimistic), that reflection is still up to 10% beam intensity. With the new MSR lamp: 10% of 'dangerously intense UV' will still be 'too much UV', if I am remembering my higher math correctly.


----------



## BVH

*Re: Scored a Nice 16" Parabolic Reflector. HID or Short Arc? Test Beamshots w/ HID.*

I have a pair of #3 and a pair of #5 clip-on, flip down official welding glasses I use when in close-quarters taking beam shots against my light colored garage door (actually 3/8" thick limestone tiles are getting hit by the spot) The #3's are recommended right in the Spectrolab NightSun manual but I found that the #5's are more comfortable blocking more of the light. Look at the bottom of the chart in the first link to see that they protect from all the dangerous wavelengths.

ww.who-sells-it.com/cy/elvex-2925/elvex-2008-safety-glass-catalog-14636/page-1-fullsize.html

Next link is just a search on Amazon for welders flip-up glasses. They're cheap at about $15 to your door. Buy both.

ww.amazon.com/s/ref=nb_sb_noss?url=search-alias%3Daps&field-keywords=%233%20flip%20up%20welding%20glasses

I also have some number 10 and 12 arc welders pieces of glass that go into the helmet. I use those to sometimes look at the actual arc. I found that using a #12 and a #3 or #5 in combination is more comfortable than just the #12.

On safety, also try to determine if the lamp you are going to use is ozone-free. Many are, some aren't so you don't want to use them in confined/closed areas. You really should be able to get a UV emissions spec on a commercial lamp. And definitely try to eliminate as much as possible the back-scatter. I haven't had to deal with that issue with my commercial made lights.


----------



## JP Labs

*Re: Scored a Nice 16" Parabolic Reflector. HID or Short Arc? Test Beamshots w/ HID.*

Excellent, thanks for the links. 

I will look around more for a UV emission spec. 

---

Edit: Here is the spectrum.

As I mentioned above, this lamp has no outer glass UV filter envelope, thus is emits a lot of UV that needs to be respected. It really does.

There is a lot of UVA (315 nm - 400 nm) and UVB (280 nm - 315 nm), and even some UVC (Ionizing UV, 100 nm - 280 nm). UVC is what makes ozone and rips molecular bonds apart, in general. It is not present in sunlight at earth's surface. The atmosphere absorbs it, making ozone in the process.

There appears to be almost as much area under the curve below 400 nm as there is in the visible part of the spectrum (*400 nm - 700 nm*) !

This is why I am being wary of the hazard.


----------



## JP Labs

*Re: Scored a Nice 16" Parabolic Reflector. HID or Short Arc? Test Beamshots w/ HID.*

My pair of MSR lamps were waiting for me when I got home about an hour ago. 

These were both supposedly new, and the pair was priced for the cost of one retail new lamp. eBay, sale not auction, from a dealer of professional DJ lighting equipment. Imagine my dismay when one of the lamps was apparently a failed lamp. There are a bunch of tiny drops of metal stuck to the inside on one side of the envelope, and the electrode gap is too big. 

_EDIT: maybe not failed completely, but certainly not new and unused, either. There is a pic below. New lamp pics don't have foggy, metal droplet covered interiors or metal on the electrodes. This supposedly new lamp did. _

I didn't even open the other lamp to inspect it; I am pretty disgusted right now. No return policy from seller, but I am offering him the chance to accept a return, anyway. I hope not to have to use the dispute process. 

Trying to be optimistic rather than cynical...maybe he is some old guy with bad eyes. But I kind of doubt it. Seems a dealer of gear would know better. Fortunately, I have had very few incidents like this, in a whole lot of purchases.

I was hoping to have this light together to bring with us on a trip to the boonies in a week. Not looking good now - I still don't have a ballast to power it, and still no lamps I can test ballasts with. 

I will order an actual new lamp from a more reputable source, after I get my refund.


----------



## BVH

*Re: Scored a Nice 16" Parabolic Reflector. HID or Short Arc? Test Beamshots w/ HID.*

That's very disappointing! I know how you feel, sort of. My Newport 1000 Watt arrived today damaged. The front left corner of 1/8" or thicker Alum was bent 90 degrees+ into the faceplate. It was advertised as most likely a new and unused unit which it looks to be with unopened manual/power cord bag. In my case, the seller had two of the same and he will be shipping me the 2nd unit tomorrow at no cost. I guess I'm lucky this time. It was packed reasonably well except for the front, only 1.5" of wrapped spray foam.

Sorry about you setback!


----------



## BVH

*Re: Scored a Nice 16" Parabolic Reflector. HID or Short Arc? Test Beamshots w/ HID.*

Sent some PM's on Ebay items


----------



## JP Labs

*Re: Scored a Nice 16" Parabolic Reflector. HID or Short Arc? Test Beamshots w/ HID.*

*Quick update: *( I will post more info and pics later when I have time)

I have been busy with this, again. 

The seller of the two MSR lamps adjusted the sale price with a partial refund per my counter-offer, so I do own 2 MSR 400 SA lamps. One is sealed, one is used and at least slightly damaged.

I bought a 400W Digital Universal MH/HPS Ballast from a horticultural store for $75.

I hooked the USED MSR 400 lamp up to this ballast to see if it would light. It was in a metal pipe, and I wore welding gear. The lamp struck and lit up dimly right away, then ramped up to a much higher but flickering brightness, and held steady like this for 5 minutes until I shut it down. The arc was wavering around a lot, and seemed a little bit orange/yellow, not intense white like I expected. Upon inspection after shutdown, there were now even more metal blobules in the envelope, and the electrodes seemed to have sustained further damage.

After cooling, I repeated this operation for 10 min. Then for 20 min. Then for 40 min. My thinking was that maybe the lamp didn't get hot enough, and it might improve. It did not improve. Always flickering. Electrode damage progressed each time. I will post close-ups showing this, later.

So, this cheap ballast does not work with a used MSR 400 SA lamp. Perhaps this is because I used a lamp that was damaged. Maybe the new lamp would work. But, I really doubt it, and I have not dared to try it. 

The ballast Lightsward suggested above MIGHT work, but I'm not confident of that, yet, and it's a $300-400 gamble to find out.

Since I have not found a source for a proper ballast intended for this wonderfully spec'd MSR SA lamp, I will try a different approach next.

I have now purchased one of the lab grade Oriel Short Arc housing and ignitor sets discussed above. No power supply, yet.


----------



## JP Labs

*Re: Scored a Nice 16" Parabolic Reflector. HID or Short Arc? Test Beamshots w/ HID.*

I got the Oriel equipment for a good price via 'make an offer' so it is not a big risk. It is designed for true Short Arc Xe or HgXe lamps, and not suitable for the MSR lamps. Oriel's starting voltage is something like 40 kV, so I think a double-ended lamp is needed for HV isolation distance. The lamp holders for single-ended lamps like the MSR are typically only rated for 5 kV. 

I still want to use the 30k Lumen 400W MSR lamp if I can. MSRs are MUCH easier to mount and keep at their happy temperature, and they can run in any position. They are AC lamps. 

The Oriel gear is DC power. The Short Arc lamps I could run with the Oriel equipment would be XBO or HBO type lamps. 200W are the biggest common size for the lamps and power supplies, although the 200W power supplies are technically capable of 300W according to the documentation. HBO 200W lamps put out only 10k Lumens. Smaller arc, sure, but I think that might be overkill with my big reflector; 3x more Lumens from the MSR is my strong preference. 

I will keep looking for a proper ballast for the MSR lamp, but I'll probably grab a 200W Oriel power supply next, and a lamp to run with it. 500W 110V Oriel power supplies are available, but awfully expensive - so much so that it would be cheaper to just buy a new, complete 575W MHI lamp Fresnel production light from China. If I could find one cheap that would make for a nice setup, though.
*
With an Oriel 200W universal supply (Model 68805) is the HBO200 is my best lamp option, I think?*


----------



## FRITZHID

*Re: Scored a Nice 16" Parabolic Reflector. HID or Short Arc? Test Beamshots w/ HID.*



JP Labs said:


> I got the Oriel equipment for a good price via ............... Smaller arc, sure, but I think that might be overkill with my big reflector; ..........



Um.... I'm confused... "overkill"? This is not a phrase I'm familiar with.


----------



## JP Labs

*Re: Scored a Nice 16" Parabolic Reflector. HID or Short Arc? Test Beamshots w/ HID.*

OH, here are pics of the MSR testing. I hope I have kept the pics of each test straight - I took way too many and should have put labels in the pics, but didn't. 

These are high res, you can blow them up for a closer look by clicking at the top banner of each as usual. For highest resolution, though, click the image itself to go to Photobucket, hover briefly over the image that loads there, then click the magnifying glass icon.

This is the inverter:




Here is the lamp as received:




Here is the lamp holder in the test rig:




Pipe and screen added for burst protection. No fan cooling; the MSR lamps are passive cooling capable:




Lamp running near end of 10 min test, the 2nd run, I think. This is outdoors on a sunny afternoon, but in the shade:


----------



## JP Labs

*Re: Scored a Nice 16" Parabolic Reflector. HID or Short Arc? Test Beamshots w/ HID.*

Close-ups of lamp envelope and electrodes after various runs are below. Over the course of the testing, the electrodes clearly degraded. The metal droplets move around a lot from test-to-test, too. Some light scratching is visible on the outside of the quartz envelope, too. This in not from me; I only touched it with an alcohol dampened Kimpex wipe, nothing hard.

*This lamp looks like is has way too much metal inside for it to simply be the mercury added for lamp operation, right?* Photos of new lamps show nothing like this, at all.

This is after a 10 min run. Note there is now a large glob of metal on the lower electrode, and appears to be less on the glass:










This is after a 20 min run. Note the red deposits....mercury can form red salts/pigments, I think. There is also now much less metal on the electrodes, and more on the glass:













Any observations are welcome!


----------



## JP Labs

*Re: Scored a Nice 16" Parabolic Reflector. HID or Short Arc? Test Beamshots w/ HID.*

Here is a photo taken as quickly as I could after shutdown, so I could try to judge if the 2 electrodes were at similar temperature. It is blurry, but shows the upper one is only running a little hotter than the lower one, by my interpretation:




And here's one after another 10 min run. This time the electrodes have a lot less metal condensed on them, but they are showing damage. The amount of metal on the electrodes seems quite small now, and there isn't a lot on the glass, either. 

*Where the heck did all that liquified-looking metal go?*:


----------



## JP Labs

*Re: Scored a Nice 16" Parabolic Reflector. HID or Short Arc? Test Beamshots w/ HID.*

Here are some shots after one more run, about 40 min or so. Electrodes seem to be in bad shape to me. I have put maybe 80-90 min total runtime on it now:


----------



## FRITZHID

*Re: Scored a Nice 16" Parabolic Reflector. HID or Short Arc? Test Beamshots w/ HID.*

That bulb is def shot. In fact, please be careful using (don't) and handling it at this point.
I have a few 150w hg/xe sa bulbs with this same issue, one burst upon cooldown, another popped in my hand while simply moving it.


----------



## JP Labs

*Re: Scored a Nice 16" Parabolic Reflector. HID or Short Arc? Test Beamshots w/ HID.*



FRITZHID said:


> Um.... I'm confused... "overkill"? This is not a phrase I'm familiar with.



Yes, I know what you mean. 

In this case, I mean that for my goal of a highly visible beam, 3x more Lumens at 1/2 the arc size ( MSR vs "100W" HID baseline) would help a lot more than keeping Lumens at 10k but shrinking the arc size further. (200W HBO vs. "100W' HID baseline).

If I go the route of the Oriel gear and an HBO 200 lamp, I will have similar Lumens to the cheap, easy HID option, but with maybe 1/3 arc length (3x surface brightness???), at 10x the cost! 

If I could make the MSR work, I would get 3x the Lumens as either HID or HBO options (30k), and still have about 1/2 the arc size of HID, so maybe *6x* surface brightness while tripling Lumens, vs HID! Seems best by far, just not working out for me, yet.

I am not very sure of arc lengths or surface brightnesses stated above; I didn't research this in detail.


----------



## BVH

*Re: Scored a Nice 16" Parabolic Reflector. HID or Short Arc? Test Beamshots w/ HID.*

As Fritz says, I'd put on very protective equipment and oh so carefully put that lamp in the trash, cover it completely and tightly with something heavy and somehow smash it.

You just don't know what you're going to end up with when running a non-matched lamp and ballast. I'm no AC short arc expert but it looks like the lamp is being very overdriven.


----------



## JP Labs

*Re: Scored a Nice 16" Parabolic Reflector. HID or Short Arc? Test Beamshots w/ HID.*



FRITZHID said:


> That bulb is def shot. In fact, please be careful using (don't) and handling it at this point.
> I have a few 150w hg/xe sa bulbs with this same issue, one burst upon cooldown, another popped in my hand while simply moving it.



OK, thank you for the caution and for confirming the lamp is shot! The metal halide short arc MSR lamps are not filled to high pressure when cold like the true short arcs. I do wear a full face welding helmet, thick leather gauntlet gloves, and a sweatshirt over a couple of layers when running it. The one exception was for the photo with the metal pipe removed. For that one, I set a 30" section of Sonotube over the lamp, and wore thinner Mechanix gloves. I used only my camera to peek over the edge. So, my hands were briefly exposed to the lamp. But I was very quick - I was worried about burning a spot on the camera's detector more than personal harm, in that event.

Your comment serves to illustrate another very good reason the true SA lamps are NOT my preferred solution. They are a lot more dangerous to handle than the MSR lamps!


----------



## JP Labs

*Re: Scored a Nice 16" Parabolic Reflector. HID or Short Arc? Test Beamshots w/ HID.*



BVH said:


> As Fritz says, I'd put on very protective equipment and oh so carefully put that lamp in the trash, cover it completely and tightly with something heavy and somehow smash it.
> 
> You just don't know what you're going to end up with when running a non-matched lamp and ballast. I'm no AC short arc expert but it looks like the lamp is being very overdriven.



OK, instead of running this lamp more, I will do as you suggest. Destroy it safely. I don't think it will burst with much energy, but I should be able to confirm that by the noise it makes. 

Overdriven makes sense. Maybe the temperature is too low, so voltage is too low and current is way too high, overheating electrodes. Maybe the ignition HV is staying on, and blasting the electrode away. I thought of trying to measure the operating voltage with my DVM, and decided that would not be smart - I don't want to probe 2 kV if the ignitor is staying on. So, I don't know.

I think it was worth a $75 gamble to try that ballast. If it had worked, I would have found a cheap route to 30k intense Lumens in a great package! 

Fail!

Now the question is if I should repeat it with the remaining MSR lamp, and hope for better results. Maybe eventually, if I give up on getting a proper ballast.


----------



## JP Labs

*Re: Scored a Nice 16" Parabolic Reflector. HID or Short Arc? Test Beamshots w/ HID.*

Fritz, 

Do you think the lamp was failed, even in the 'as received' picture, or only after I tortured it?


----------



## FRITZHID

*Re: Scored a Nice 16" Parabolic Reflector. HID or Short Arc? Test Beamshots w/ HID.*

Bvh is correct. Cover with some trash cloth (shirt, towel, etc.), 4 layers thick should be plenty, and hammer it, then toss as is.

As far as your main thread post.... it's very basic... Smaller arc = tighter/cleaner beam.... I have a fist full of lights.... from a small reflector 10/30w hid to my hack job 400w mh beast....
Watt for watt... at an honest 83watts for both tests.... true SA xenon beats all others (hid(mh "sa" ), merc/xenon, hbo, xhp......etc) as far as that laser like, super far throwing beam...
Given that the = wattage HID throws a ton more lumens down range, the beam it's huge.


----------



## FRITZHID

*Re: Scored a Nice 16" Parabolic Reflector. HID or Short Arc? Test Beamshots w/ HID.*

I believe you got a bad lamp to begin with.


----------



## JP Labs

*Re: Scored a Nice 16" Parabolic Reflector. HID or Short Arc? Test Beamshots w/ HID.*



FRITZHID said:


> Bvh is correct. Cover with some trash cloth (shirt, towel, etc.), 4 layers thick should be plenty, and hammer it, then toss as is.
> 
> As far as your main thread post.... it's very basic... Smaller arc = tighter/cleaner beam.... I have a fist full of lights.... from a small reflector 10/30w hid to my hack job 400w mh beast....
> Watt for watt... at an honest 83watts for both tests.... true SA xenon beats all others (hid(mh "sa" ), merc/xenon, hbo, xhp......etc) as far as that laser like, super far throwing beam...
> Given that the = wattage HID throws a ton more lumens down range, the beam it's huge.



OK, great input, thank you for the clear info. That makes the Oriel set up sound pretty good for performance, then. Excellent.


----------



## FRITZHID

*Re: Scored a Nice 16" Parabolic Reflector. HID or Short Arc? Test Beamshots w/ HID.*

SA lamps can be dangerous, however... As long as proper safety protocols are observed.... totally worth it. Common sense and knowledge are all our best friends.  almost anyone here with experience will be more then willing to assist you in your project as well as informing you of safety precautions.


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## JP Labs

*Re: Scored a Nice 16" Parabolic Reflector. HID or Short Arc? Test Beamshots w/ HID.*

<<< Created a more appropriate avatar for this forum. 

For reference and continuity: The old was was a gearhead - an illustrated cutaway of a head, full of gears.


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## JP Labs

*Re: Scored a Nice 16" Parabolic Reflector. HID or Short Arc? Test Beamshots w/ HID.*

I had a fascinating, extremely helpful chat with FritzHID. I learned a ton! lovecpf

I am now quite enthusiastic about the Short Arc lamp options. In fact, *I just bought the Oriel 68805 power supply* I've been watching. Now I should have everything I need to operate a short arc lamp from mains power; I just need the lamp itself.

I might have some spousal explaining to do when these big, heavy boxes show up in a week.

--
Below is partially repeat info, covered here in relevance to my pending lamp decision:

Reading more about XBO (Xenon) and HBO (Mercury) short arc varieties, I am convinced that the XBO is less suitable. 

XBO150 W/4 is a S15 orientation lamp, meaning it is supposed to run within 15 degrees of vertical With axial mounting, that means the light could only aim near the horizon. (corrected, originally said _horizontal_, but there is an error in the section of the data sheet I was using).It is the largest available XBO I can power, and makes 3000 Lumens with Luminous Intensity = 300 cd. ​
HBO200 W/2 is a S90 orientation lamp, meaning it is designed to run within 90 degrees of vertical. So, I shouldn't aim it downhill for long, but that provides a lot wider range of motion, within the intended operating position requirements. Anything from straight up, to horizontal.It is the largest HBO I can power, and makes 9500 Lumens with Luminous Intensity = 1000 cd. Average Luminance (cd/cm2): 40000
​
I still want to learn more about the Hg(Xe) lamps, in case they may be even more suitable than the HBO.

Edit: Hg(Xe) are in between the others, not surprisingly (Oriel 6292 200W). 4500 lumens. 600 cd. 

*Still liking HBO200/W2. So I just bought one*, pretty cheap for what it is, at $50. This appears to be an L1 variant, with a small internal reflective area at the bottom/cathode end. That reflector is probably not ideal...but it's what I found in the low priced lamp options.

It might only be rated for S45, depending upon which spec sheet I believe. S90 orientation is listed in Osram's general specs for HBO200W2 lamps. Hmm. Complicated.

Now I am fully committed to trying this. The week after next should be very interesting.

Mounting any of these lamps so they are electrically isolated from everything else, and can be cooled, will be a big challenge!

Thanks for all the support and encouragement.

​


----------



## BVH

*Re: Scored a Nice 16" Parabolic Reflector. HID or Short Arc? Test Beamshots w/ HID.*

If by "small reflective area", you mean a gold, painted on coating on one end of the bulbous arc chamber then the purpose of that coating is to keep that "cooler" area of the arc chamber hotter so that the Mercury does not re-condense in that area. That's what the guys at A.R.C told me.

McMasterCarr carries high-KV silicone insulated wire if you need it for the secondary run. I think up to 40KV and up to 12AWG.


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## JP Labs

*Re: Scored a Nice 16" Parabolic Reflector. HID or Short Arc? Test Beamshots w/ HID.*

Reflective coating for heating the end with the mercury more/faster, sure, that makes sense. Looks like it could block a small area of light from hitting the center area of the reflector, and will probably add that light to spill. Not much, though.

I'll order some silicone wire, good to know where to find it, excellent.

By the looks of this HBO lamp, I think the mounting barrels (metal cylinders on the ends) are electrically live, right? So, I can't machine a simple aluminum mount like I did for the HID lamp. That would not isolate the lamp from the reflector. Thus, electrocution hazard.

I have not been able to find any ready-made, ceramic lamp sockets that would work. It will take some creativity to mount that lamp such that it is electrically isolated, sturdy, and won't melt. I am thinking along the lines of a cylindrical steel clamp on the bottom/rear of the lamp, with 3 thin metal legs maybe 2-3" long. These would be in the air path, so they will stay relatively cool at the furthest ends from the lamp. This assembly could be anchored in a cylinder made of Delrin, Nylon, PVC, or similar. The whole thing would insert into the reflector just like the HID mount did. 

Maybe there will be useful bits in the Oriel lamp housing for this. I'll post internal pics when it shows up.


----------



## BVH

*Re: Scored a Nice 16" Parabolic Reflector. HID or Short Arc? Test Beamshots w/ HID.*

My housing hasn't shipped yet. Kinda disappointed in them. The cylindrical ends are call bases and conduct power and ground to the electrode rods that are welded to the top/center of the bases. Anything you make to mount them in, I call base adapters. The Cathode base for the small electrode (negative) and the Anode (positive) base for the big electrode. Most specs I've seen indicate the bases should not reach over 250C. Some higher KV lamps could certainly be different. Check out Fluorosint. Its a Mica inpregnated PTFE/Teflon material. Maybe 500C IIRC. Very expensive but a very high temp "plastic". I've used it before. Some of the Delrins won't hold up, I've softened a few in my Locators.

Be sure to control your cooling fan separate from the lamp ignition and running circuits. You want to be able to run it for a few minutes after shutdown. If you can believe it, the Spectrolab NightSun old style control box was wired to run the fan with the light so that when you turn off the light, you turn off the fan. Right in the manual it says to immediately turn the fan back on. Newer models fixed that with a different switch setup.


----------



## JP Labs

*Re: Scored a Nice 16" Parabolic Reflector. HID or Short Arc? Test Beamshots w/ HID.*

That was one info packed post ^. Online shopping time. 

My housing, PS, and lamp have all shipped. Big stuff coming slowly, though. Possibly as late as Oct 1 arrival on the housing. 

I'll be off the forum for a few days. Later guys.


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## BVH

*Re: Scored a Nice 16" Parabolic Reflector. HID or Short Arc? Test Beamshots w/ HID.*

Opps, meant 500F for the Fluorosint, not 500C. My housing should be here tomorrow.


----------



## JP Labs

*Re: Scored a Nice 16" Parabolic Reflector. HID or Short Arc? Test Beamshots w/ HID.*

Just a quick update so you guys know I am still around! I am very busy at the moment, with travel, work, collecting firewood for the winter, car maintenance, and other chores. 

My lamp, ignitor, housing, and power supply are sitting here in boxes, ready to play as soon as I can free up some time and clear up some bench space. I hope to unpack it this weekend.


----------



## Bill Idaho

*Re: Scored a Nice 16" Parabolic Reflector. HID or Short Arc? Test Beamshots w/ HID.*

I am waiting.


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## JP Labs

*Re: Scored a Nice 16" Parabolic Reflector. HID or Short Arc? Test Beamshots w/ HID.*

OK, today I finally made time to clean up shop space and unpack my toys. 

The Power Supply was very well packed:




So were the housing and ignitor:thumbsup::




But, do they work? A bit worried about the gamble.....:scowl:

Power supply lights up, and amps preset works. Good!




The housing was designed for a lamp that runs anode (+) up. My HBO200 runs anode down. So I had to install upside down for the housing, placing the arc way too low, even at full adjustment. This could be remedied with a spacer, but it's good enough for testing.


Crossing my fingers.......oo:












Will I be disappointed?











:naughty:


















Hooray!! 


It was fully warmed up within about 8-10 minutes. I ran it for about 15 minutes. 


The hot spot completely misses the optics, so the fiber cable is dim.


Next I need to start working on a lamp mount for the searchlight. Progress will be slower than before, it is a very busy time. But I hope to work on it every weekend for a while, at least.


----------



## BVH

*Re: Scored a Nice 16" Parabolic Reflector. HID or Short Arc? Test Beamshots w/ HID.*

Hurray! The power supply issue is out of the way now.


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## BVH

*Re: Scored a Nice 16" Parabolic Reflector. HID or Short Arc? Test Beamshots w/ HID.*

Nothing new?


----------



## JP Labs

*Re: Scored a Nice 16" Parabolic Reflector. HID or Short Arc? Test Beamshots w/ HID.*

Ok, I'm back. Like I mentioned, it's been busy. 

I did finally get back to playing with the light a little bit today. But first, a totally off topic diversion for a moment. This is what has used up my free time the last couple of weekends:





A wood shed and a mechanical wood splitter. The latter is a spring loaded, gravity assisted gizmo which spares me the effort of swinging a splitting maul.


----------



## JP Labs

*Re: Scored a Nice 16" Parabolic Reflector. HID or Short Arc? Test Beamshots w/ HID.*

Here are a couple more shots of it running:








The lamp is still positioned about 1/4 inch too low here, so it's a small fraction of the intended intensity.

All of the cables plugged right in. All of the various safety interlocks worked. I had to reverse the DC+ and DC- at the housing, though. The HBO lamp has + (Anode) on the bottom; it came with the Cathode connection on the bottom.





I also collected several bits which will be helpful in mounting the lamp, although in what configuration, I am not yet sure. 





Included are a 10 mm brad point drill and a 10 mm center cutting end mill, to make the pocked for the lamp base. Also a pair of 4 mm x 0.7 mm plug taps, so I can retain lamp in my pending custom heatsink, using the threaded terminal at the very end of the lamp.


----------



## JP Labs

*Re: Scored a Nice 16" Parabolic Reflector. HID or Short Arc? Test Beamshots w/ HID.*

The Delrin and PVC pieces shown above will be used for electrical isolation. The heat sink will be machined down to fit inside a cylindrical plastic housing which attaches to the reflector. So, only the cool, outer edges of the fins will touch plastic. 

I need to devise the means of lamp positioning before I go much further.

Here is a shot on the inside of the lamp housing. Note the mechanism at the left. This positions the reflector in x,y,z axis. I would like to convert this for lamp mounting use, but it will be very difficult to keep the forced air cooling if I do. The body has no passages for airflow, and it fills the ID of the reflector fairly tightly. 





Isn't it pretty in there?

Here is the outside view:





And here it is, removed - it is the round piece to the right. The black one is the shutter assembly and a 'dark shield' interlock:





The entire inner assembly, the gray and the silver parts, move in and out about 0.240". The silver part angles up/down, left/right PLENTY far. I would like more z and less x,y, but the mechanism is almost perfect for the job. Except for the lack of an airflow path. 

I could simply make the lamp adapter long, like 4" instead of 2", and feed the cooling air in from the side instead of axially, but I really don't want much excess length hanging off the back of the reflector. Worse, I think, is this solution would require the lamp to be cantilevered a long ways out from the adjusting mechanism. That would not be good for precision. 

I could also do a simple 3-screw mounting with springs under the screws. But, then, all 3 screws need to be turned for any adjustment. I want one just for focus, and two independent ones for the x,y.

Next, I need to make the heat sink, play with the pieces for a while, and think.


----------



## JP Labs

*Re: Scored a Nice 16" Parabolic Reflector. HID or Short Arc? Test Beamshots w/ HID.*

I figured out the necessary dimensions to mount the lamp and center the arc at the reflector's focal point. 

The arc location is 1.575" (40 mm) from the face of the lamp's Anode end. The parabola has an externally threaded mounting sleeve that was not shown in the original drawing, but is sketched in, below. 

This drawing is marked up to reference the arc location to the rear flange of that mounting sleeve. 





A 2" schedule 40 PVC pipe is a slight interference fit with the smooth ID of that threaded sleeve. So, I can use the PVC as the first layer of HV isolation, between the lamp adjuster and the reflector/frame assembly. This will enable gross tuning of lamp center, to enable a range of lamp sizes to be fitted.

I think, with a little creativity, I _will _be able to use the x,y,z mirror stage from the lamp housing as my lamp adjuster. 





Here it is disassembled, below. The part on the left is the part that moves in and out, z axis. The tilting stage (x,y) is on the bottom of that, barely visible through the hole and under the bottom edge.

The part on the right is the rear cap, upside-down in this view:






Here is the x,y stage removed from the end of the z axis piece:




Remember that the positioning stage had no airpath. Well, it does now. Almost. I turned down part of the OD to allow annular airflow. Then I cut a path in the front face to spread air out in the gap between the z axis part, and the x,y part:





Finally, I hogged out a few gaps between key features I can't ruin, from the outer lip around the front face. The result is an air path to feed cooling flow from a fan mounted to the side of the mounting tube, to the back of the x,y stage. 

Below is a VERY rough approximation of how the parts will interface. Note that the main mounting tube, a piece of 2" PVC, is NOT shown here. It will be attached to the flange of the 'top hat' in this picture, and will cover the whole assembly, except for about 0.5" of the heatsink. There will be clearance inside that tube for the guts to move. 

A small blower will be located on the side closest to the camera, mounted to a hole in the (not shown) outer PVC mounting tube. The PVC shown here represents the 2nd layer of HV isolation, to which the heat sink and lamp assembly will be mounted. I might use Delrin or Nylon instead, but you get the idea. 

The heat sink will wind up only about 2" long and will be partly nested inside the insulation piece:





I still need to drill holes in the x,y stage to feed air to the back of the heat sink.

Here is the 12v blower I found. It is 3" across by about 1" thick, quiet, and powerful enough for this task, I think:





Next, I need to figure out how, exactly, I am going to mount the whole thing to the reflector such that there is room for the adjustment range, and airflow. Then, machine a suitable heat sink from that giant donor, above, and start putting it all together.


----------



## FRITZHID

*Re: Scored a Nice 16" Parabolic Reflector. HID or Short Arc? Test Beamshots w/ HID.*

Just keep in mind that the pvc may gasoff and cause deposit issues at those temperatures.


----------



## JP Labs

*Re: Scored a Nice 16" Parabolic Reflector. HID or Short Arc? Test Beamshots w/ HID.*

I think it will be pretty cool there, as they will only touch the outer, coldest part of the heat sink fins. The PVC will be directly fan cooled, too. But thanks for the suggestion; I will watch the temperature and keep an eye on the reflector and glass for any fogging.


----------



## get-lit

*Re: Scored a Nice 16" Parabolic Reflector. HID or Short Arc? Test Beamshots w/ HID.*

Congratulations on your venture. The beam this will throw will be incredible.

Keep in mind, only certain short-arc lamps benefit from heat sinks. Lamps with Molybdenum "foil" seals don't benefit from heat sinks. Only lamps having seals with rod construction benefit from heat sinks because only the rods are thick enough to transfer the heat.

Lamps with rod seals are much longer because they have graduated construction to compensate for the expansion differences between the quartz and the electrode shafts, whereas Molybdenum foil in smaller lamps is close enough in thermal expansion to quartz to be usable up to a certain foil size. Only the higher powered multi-kilowatt lamps have the rod construction, because it's a more involved construction and the more simple foil seal construction can't be used because foils have a maximum electrical current due to the limited foil size required for maintaining a seal before the difference in thermal expansion becomes an issue.

But the foils are not thick enough to conduct practically any heat away from the seal to the heat sink. I had to change my plan after I found this out the hard way. Foil seals need direct air flow to cool the seal. In my testing, even very large blocks of copper heat sinks did absolutely nothing to assist in cooling the seals. Unfortunately you'll likely have this issue too, as the lamp you're using has foil seals. To be fully assured of lamp seal cooling effectiveness in the enclosure, you'll need to obtain from the lamp manufacturer a modified lamp having thermocouples embedded into the seals.


----------



## JP Labs

*Re: Scored a Nice 16" Parabolic Reflector. HID or Short Arc? Test Beamshots w/ HID.*



get-lit said:


> Congratulations on your venture. The beam this will throw will be incredible.
> 
> Keep in mind, only certain short-arc lamps benefit from heat sinks. Lamps with Molybdenum "foil" seals don't benefit from heat sinks. Only lamps having seals with rod construction benefit from heat sinks because only the rods are thick enough to transfer the heat.
> 
> Lamps with rod seals are much longer because they have graduated construction to compensate for the expansion differences between the quartz and the electrode shafts, whereas Molybdenum foil in smaller lamps is close enough in thermal expansion to quartz to be usable up to a certain foil size. Only the higher powered multi-kilowatt lamps have the rod construction, because it's a more involved construction and the more simple foil seal construction can't be used because foils have a maximum electrical current due to the limited foil size required for maintaining a seal before the difference in thermal expansion becomes an issue.
> 
> But the foils are not thick enough to conduct practically any heat away from the seal to the heat sink. I had to change my plan after I found this out the hard way. Foil seals need direct air flow to cool the seal. In my testing, even very large blocks of copper heat sinks did absolutely nothing to assist in cooling the seals. Unfortunately you'll likely have this issue too, as the lamp you're using has foil seals. To be fully assured of lamp seal cooling effectiveness in the enclosure, you'll need to obtain from the lamp manufacturer a modified lamp having thermocouples embedded into the seals.



Hello, get-lit. Thanks for dropping by and offering your kind, helpful input! I really enjoy your writing, your fascinating beamshot simulations, and the Nightsword design discussions. You have a well honed, BEAUTIFUL design, there. Impressive design/engineering skills!

That is some new info to me, about the thermal path effectiveness of Mb foil seals, vs rods. It makes sense, but I was not aware of the distinction, and frankly didn't even know about the difference in these alternative designs. 

So, if I understand correctly, *in the case of a high pressure Hg lamp, with Molybdnum foil seals, which requires forced cooling*: the cooling requirement is to keep the foil seals from melting or being overstressed due to differential thermal expansion vs the quartz. You don't want to overcool the quartz envelope itself, however, as that would lower the operating mercury pressure, hurting efficiency and possibly resulting in Hg condensation on the quartz during operation. So, you have to direct air at the two straight sections on either end of the lamp, rather than at the metal caps on the ends, because the thermal path to the metal caps is poor.
Correct so far?​ 
So, my configuration will not work *for Mb foil seal lamps that require forced cooling*. I would need a different, more complex airflow arrangement to actually cool the quartz shafts of the lamp without cooling the spherical envelope. 

*In the case of a rod-style lamp that requires forced cooling,* the rods carry heat to the end caps more effectively, allowing the caps, or a heat sink in thermal communication with the caps, to be the forced-air target, and still keep the Mb rods cool enough. In this case, the rods would help cool the electrodes themselves, too. I could run such lamps in this configuration, assuming the cooling rate is correct for each lamp end.
Still good?​ 
The Osram HBO 200 W/2 lamp I am using now is a Mb seal type lamp, as you observed. Remember, it is a very high pressure Hg lamp, not an Xe lamp. From the spec sheets I have seen, it says 'passive' in the column for cooling requirements. The larger lamps (HBO1000 for example) will state an air velocity requirement in this same data field. So, I think this lamp does not  require forced air cooling.
Would you agree that I am interpreting this specification correctly?​ 
There is also a maximum temperature listed for the HBO200 lamp base ends, in this case 250C. So, I could actually run this lamp with no cooling, as long as the base stays below 250C. Because it is undesirable to overcool the envelope of a VHP type Hg lamp, the less cooling, the better, to a point. The lamp needs to reach design temperatures to work well, mostly due to the need to achieve high Hg gas pressures.

My reason for using forced air cooling with the HBO200 is not to cool the lamp itself, but to enable me to use relatively low temperature plastic as my HV isolation material. If I simply installed the lamp directly into a plastic base, I would achieve the necessary HV isolation, but the plastic would be insulating the lamp base end, and elevating it's temperature. And the plastic would soften, expand, and perhaps melt. So, I am using a heat sink to make my lamp mount. The cooling air only needs to reduce the temperature of the heat sink enough so that is can interface to plastic without softening it. The plastic will be further cooled by the airflow. The airflow path will be such that there is no direct impingement upon the round lamp envelope. So, I don't think I need to change the configuration for this HBO200 lamp, I think I am ok.​ Other reasons for my adding (filtered) forced air are to minimize ozone accumulation inside the light, to keep overall temperatures of the lamp low, and to discourage bugs, dust, or rain from coming inside.
Does my approach make sense in this context, and do you think it will work for this lamp, considering the lamp's passive cooling rating?​ 
Note that the Oriel housing I have is rated for this lamp. It simply uses a chunk of brass as the mount at the lower end of the lamp. A fan provides some airflow to purge the housing of hot air, with no airflow directed at any part of the lamp, and minimal flow at the brass base. There are metal light baffles between the fan and lamp which cause a diffuse, low velocity airflow through the housing, mostly near the walls. See pic a few posts up.


----------



## JP Labs

*Re: Scored a Nice 16" Parabolic Reflector. HID or Short Arc? Test Beamshots w/ HID.*

FRITZHID, in consideration of your comment about outgassing from hot PVC, I took a better look at the fit of the parts, and what I might do to further increase air velocity over the PVC. I went back to the lathe and reduced the OD of the x,y plate further (about 0.090"). This will increase the bypass airflow around the outside of the heat sink holder, which will pass more air between the OD of the PVC heat sink holder, and the ID of the PVC mounting tube. Now, I am actively cooling the full length of 3 of the 4 cylindrical PVC surfaces, instead of just the inside of the piece holding the heat sink.





I also carved up the x,y plate to add airflow passages to feed the heat sink:




This shot shows the PVC heat sink holder mounted to the x,y plate. It is tapered to allow for tilt of the assembly inside the main mounting tube. The heat sink will be similarly tapered. Alignment is not perfect; this was 2AM and things were getting blurry, but I was on a roll. I will need to true it up on the lathe again, to make the heat sink concentric with and parallel to the x,y base:





In this view, you can see a semi-circular cutout in the left side, near the bottom of the PVC. This is where the HV + lead will exit from the lamp holder assembly. It will pass through the outer PVC mounting tube. I hope it is flexible enough:




For HV isolation, the closest point between the high voltage and the parts that need to be HV safe will be a 0.500" air gap. This is about 4x the arc gap distance. This clearance will exist between the screw which retains the HV lead to the bottom of the heat sink, and the center of bottom surface in the above x,y plate. I could add a plastic baffle here if this is insufficient, but airflow would suffer. I will probably make a plastic cap to cover the fastener, to improve the resistance at this path without blocking much air. HV only exists in the circuit for a fraction of a second while the 'ignite' button is pushed, and the only metal which is potentially exposed via this path is the x,y,z assembly, not the frame or reflector. So, exposure risk is pretty low, but I would like to maximize the isolation within design limitations, of course. Still, an important safety consideration will be to never attempt to strike the lamp while adjusting it's position.

Today I will work on heat sink machining.


----------



## JP Labs

*Re: Scored a Nice 16" Parabolic Reflector. HID or Short Arc? Test Beamshots w/ HID.*

One slight concern for me now is that this configuration, with a HV live metal heat sink inside two layers of plastic, inside a grounded metal parabola, is basically a capacitor. Hopefully, it will not be a problem for the power supply to have this added capacitance in the system.


----------



## get-lit

*Re: Scored a Nice 16" Parabolic Reflector. HID or Short Arc? Test Beamshots w/ HID.*

Ahh.. I didn't realize this is 200W, which may not require forced air cooling. I know 100W doesn't, but I was under the impression that 200W was on the threshold, yet recommended. According to that spec sheet, I'd say convection is fine.


Yes, if it required forced air cooling, it "should" be air directed onto the seals themselves. A slow steady flow of air perpendicular to the lamp is perfect. The amount of airflow required onto the seals is plenty low enough that it would not negatively affect envelope temperature whatsoever. This kind of air flow was not practical for my configuration. I spent a lot time testing with thermocouple lamps to find a work-around so that inline air flow could be used to cool both seals without over-cooling the envelope.


If you're sure your lamp doesn't require forced air cooling, then instead of using forced air to cool the HV wire, I'd insulate it with a better material. I'd simply insert the HV wire into solid but bendable *PTFE tubing* and stick with convection cooling.


----------



## JP Labs

*Re: Scored a Nice 16" Parabolic Reflector. HID or Short Arc? Test Beamshots w/ HID.*



get-lit said:


> Ahh.. I didn't realize this is 200W, which may not require forced air cooling. I know 100W doesn't, but I was under the impression that 200W was on the threshold, yet recommended. According to that spec sheet, I'd say convection is fine.
> 
> 
> Yes, if it required forced air cooling, it "should" be air directed onto the seals themselves. A slow steady flow of air perpendicular to the lamp is perfect. The amount of airflow required onto the seals is plenty low enough that it would not negatively affect envelope temperature whatsoever. This kind of air flow was not practical for my configuration. I spent a lot time testing with thermocouple lamps to find a work-around so that inline air flow could be used to cool both seals without over-cooling the envelope.
> 
> 
> If you're sure your lamp doesn't require forced air cooling, then instead of using forced air to cool the HV wire, I'd insulate it with a better material. I'd simply insert the HV wire into solid but bendable *PTFE tubing* and stick with convection cooling.



Yes, with this power supply, 200W is about as big a lamp as I can run. I may try the HBO100 at some point, too. That model has the highest surface brightness, by a pretty wide margin. It will be interesting to see if that is visibly better than the 200.

It is the lamp mount, made from a heat sink, that I am trying to insulate against HV leakage. Not the HV wire, itself. That is 50 kV High Tension lead.


----------



## JP Labs

*Re: Scored a Nice 16" Parabolic Reflector. HID or Short Arc? Test Beamshots w/ HID.*

OK, I did some more work today. Here is the heatsink, bottom view. The OD is turned down, there is a step to fit the PVC collar, and a screw for the Anode wire is fitted:




That screw is aligned to be accessible through one of the cooling holes. I made a longer plastic part so the air gap from that screw to the metal plate is increased to 1":




Lamp fitted. This assembly is the same diameter as the hole in the reflector. 

It is now evident that the silvered section at the bottom of the lamp envelope will shadow a pretty large portion of the parabola, perhaps a 6" circle in the center. This may be a critical flaw. 

* Is there any way to partially remove this silvering?*





Added a brass disc to direct the exit air outwards, instead of at the lamp:




Here it is mounted on the x,y,z positioner:




In this shot, it has been assembled to the mounting tube, which inserts into the parabola's threaded sleeve:




Like this:




Next step, add a cutout and mount the blower. Also the anode wire. Blower goes about here:




Note that these PVC parts were machined on nearly all surfaces. ID, OD, ends. They were convenient donor material. It would not be an easy task to turn tubes from solid Nylon stock, and plastic tubing in the right sizes and materials was elusive. This worked well, so far at least. We will see how it holds out once I turn up the heat.


----------



## get-lit

*Re: Scored a Nice 16" Parabolic Reflector. HID or Short Arc? Test Beamshots w/ HID.*

It's turning out very nicely. The lamp reflective coating is internal. There may be a version of the lamp available without that coating.


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## BVH

*Re: Scored a Nice 16" Parabolic Reflector. HID or Short Arc? Test Beamshots w/ HID.*

Your above post was fun to go through. Anxious to see it lit and the long range beam shots.


----------



## JP Labs

*Re: Scored a Nice 16" Parabolic Reflector. HID or Short Arc? Test Beamshots w/ HID.*

Me too! Beam shots may be a while. At least from anyplace remote where I can hit any distant targets. After several hours more work I should be able to bench test it to get some temperature measurements, though.

I'm going to need to make some kind of a cart to support this heavy rig, rather than the tripod I currently use. I intentionally mounted the light above eye level in the prior iteration, to prevent folks from looking inside while it's aimed straight up in beacon mode. I should do that again. 

Of course, I still need to check the PS on inverter power, too. I don't have the guts to try that yet; need to at least run it on grid power for a while first - it would be sad to kill this PS so soon! 

I did finally order some 50kV cable to extend the leads. I need to figure out how to go about splicing this safely, if I want to keep the stock PS and ignitor connections. Or, maybe I can un-crimp and re-crimp the rather unique terminals to make new wire runs with the old connectors. Can this stuff be soldered, or is crimping required?

 More thoughts on the reflective area of the lamp:
While I was surprised to see how much of the reflector will be in shadow, I guess it is not so bad. I had been thinking of it only as a loss in lumens, but really, I am still using the 'best' part of the reflector - the larger diameter portion. And the variation in distance from arc over the usable portion of the reflector will be less than if I used the entire reflector. So, optically, it should colimate even better than if the entire surface was used. The unfortunate part is that a significant portion of the lamps output is redirected outward by that internal reflective area, so lumen utilization is not so good and spill will be greater. BVH encouraged me not to worry too much about this earlier, and I am starting to understand why.

If I could invert the lamp to put the reflector at the top, that would increase Lumens focused, and would reduce the unfocused light output. The lamp is nearly symmetrical and is optionally rated for AC use, so it might last a while that way, especially if I started the lamp in proper orientation (pointed at the ground in this case) when heating the mercury condensed at the bottom Anode is critical. It could be rotated it upright after warm-up, and pointed down again for shutdown and cooling. This should work fine for horizontal use, but for aiming straight up, maybe not. Lamp is not rated for inverted use in any circumstances, but perhaps that is due to starting and shutdown orientation requirements. 

Also, with the lamp installed upside down, the cathode end would be cooled, not the anode. Combining that with the inverted orientation could be pushing the thermal conditions too far. I don't dare try any of this for a while. Maybe if output is disappointing - which I am not thinking will be a problem!

One more thing - while the tempered glass cover lens "probably blocks enough UV to be relatively safe", that is not good enough for me. I also ordered a sheet of clear UV filtering 'window security film' in 4 mil thickness. I will laminate that to the outside of the cover lens. It will ensure the UV A and B are at low levels. I may lose another 5-10% output (wild guess) but it seems a prudent measure. That film will help contain the glass in case of breakage, too. Unfortunately, it will scratch easily if on the outside, but I don't think it would survive for long on the inside surface, with rampant UV levels.


----------



## FRITZHID

*Re: Scored a Nice 16" Parabolic Reflector. HID or Short Arc? Test Beamshots w/ HID.*

In my experience, splicing HV wires is very risky... each splice, no matter how well done, is a weak point.... the slightest gap or air space is a point of failure... I suggest total replacement.....
That being said, I HAVE used adhesive heatshrink tubing in multiple layers on HV but it makes the wire bulky and can cause gasoff issues in some cases.


----------



## BVH

*Re: Scored a Nice 16" Parabolic Reflector. HID or Short Arc? Test Beamshots w/ HID.*

I recently came across a bunch of clear shrink tube I bought years ago that is KV rated. I was going to toss it....but just couldn't so I still have it. I don't remember much about it so I'll try to find it again to get a brand name or other info so I can look up the specs. If the specs are good enough, you can have some of it. As Fritz has done....I've spliced quite a few HV wire runs and used 4 layers of non-adheasive shrink tube with success. Mostly with automotive ballasts applications, including a couple of 80 Watt Blitz HID conversions which strike somewhere around 30 to 35 KV.

The only Short Arc lamps I have seen that utilize heat sinks at one or both ends are the Cermax/Luxtel ceramic body lamps. I've not seen one conventional SA lamp with a heat sink in either convection or forced air cooling applications. You might be over-engineering this, but that's just a shot from the hip, so to speak. Maybe take some temp measurements with an IR Thermo and see where you're at.

Just a quick search returned this 36KV rated tube for bus bars.

http://www.shrink-tubing.com.tw/high-voltage-isolation-tubing/hb3.html


----------



## JP Labs

*Re: Scored a Nice 16" Parabolic Reflector. HID or Short Arc? Test Beamshots w/ HID.*

Thanks for the splicing comments.

Yes, I am probably over engineering it! That's half the fun. I want a vented enclosure, so may as well make the most of the airflow, too. 

The heatsink and plastic are both non-black surfaces, so won't read accurately on IR unless I paint them. I will stick an insulated thermocouple onto the plastic/heatsink junction to check temp. 

I did get the blower mounted and the anode wire installed. Then I blew all the dust out with 90 psi, and blew up my blower's wheel. I grafted the axial fan on for a test, and it works OK, but it's loud. I will get another blower. But this will work for testing.

Next step, bench test the lamp & mount assembly. Might be a little while.


----------



## JP Labs

*Re: Scored a Nice 16" Parabolic Reflector. HID or Short Arc? Test Beamshots w/ HID.*

I finished the fan, wiring, and tested the light in the shop tonight. I'll get to the pics later. Here's what I learned:

Once I thought about it, I couldn't measure temperature as intended - the heat sink is live and the thermocouple wire is conductive. So, I didn't. Nothing melted.

This HBO lamp does NOT like much cooling. With the blower on, the lamp would strike fine, but would not warm up. It got to about 50W and stopped climbing. I reduced airflow to about half, but that didn't help much. So I turned the fan off. Lamp warmed up as normal, over several more minutes. At 200W, it required 3.3A. Turned fan back on, power began to slowly drop again. But at only 3.4A, it stabilized at 200W again, working fine. Rated amperage is 3.6A, so mine is still running a little low. Probably not significantly overcooled, at least, as more cooling drives amperage up to maintain power.

With the fan on, the ozone smell is pretty strong. I opened the garage door.

Seems to focus OK. The only thing I could hit from the shop was a transformer on a pole, maybe 25 yards away.

*The spotlight runs fine pointed straight up. Decent at 45. But it won't run horizontal! *  

It acts like it cools off again. It dims over a minute or two, power dropping, voltage dropping, amps constant as set. 

Stopping the fan didn't help. Cranking the amps did help a little, but I only went up to 4.1A. That is 14% more than rated, and 24% more that it required to run vertically. This allowed it to stabilize at about 90 Watts. Output was significantly reduced. No visible flickering or anything odd. It behaved like it does when too cool. Very low voltage, about 22V - another indication that the mercury pressure is too low, thus not hot enough.

Lamp looks fine after shutdown. 

I did find conflicting info about orientation for the HBO when I was researching it. One spec sheet said S90, one said S45. I guess S45 is correct (+/- 45 deg).

Has anybody else actually used an HBO lamp in a spotlight? If so, did this occur? Any suggestions? 

If not, are there any known short arc Hg lamps that WILL work both horizontal and vertical? What DC SA lamps work, in general?

I know I've seen beamshots taken horzontally in the short arc threads, but I don't remember any discussion of the stability of lamp operation in that orientation. Or anybody that specifically used a super high pressure Hg type lamp, really. Xenon, yes.

Maybe I just need to crank the amps, readjust every time it's aimed? Cumbersome. Don't want to blow the bulb. The L2 version of the lamp (kind of like an LED bin, I think. The lower end of the voltage variation) runs at 4.2A for the same 200W. I think 10-15% overcurrent is within reason, so maybe I could try as much as 4.8A without worry.

I think the Xenon lamps are better for horizontal output, right? Lot fewer lumens though.

I wonder how badly my new MSR400SA would behave, driven on DC.

3rd lamp tried. 2nd failure. Discouraged.


----------



## JP Labs

*Re: Scored a Nice 16" Parabolic Reflector. HID or Short Arc? Test Beamshots w/ HID.*

Here's the air inlet:




Blower mounted:




Filter added:




There was noticeable air motion at the lamp envelope, so I added a bigger air deflector around the base:


----------



## JP Labs

*Re: Scored a Nice 16" Parabolic Reflector. HID or Short Arc? Test Beamshots w/ HID.*

I only made one HV splice on each cable, for the Ignitor connectors. I am confident it is adequate. Overkill, I think. Here's how I did it:

Load 4x heat shrink on each cable.




Solder:




Rubber tape:




Liquid Insulation:




Slit vacuum line:




Then another layer of the liquid insulation, then the heat shrink:




Ready to go:


----------



## BVH

*Re: Scored a Nice 16" Parabolic Reflector. HID or Short Arc? Test Beamshots w/ HID.*

Great pics. I have only 1 HgXe and that is the 300 Watt Locator. It runs fine from 5 degrees below horizon to vertical. It uses a small fan to recirculate the air within the glass dome. No air is exchanged.

Today, I did some high voltage wire splicing of my own on the Target Source. I used 5 layers of non-adheasive heat shrink with no issues. My closest distance from + to - is about 5/8".


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## JP Labs

*Re: Scored a Nice 16" Parabolic Reflector. HID or Short Arc? Test Beamshots w/ HID.*

I laid polycarbonate sheeting over the light to kill any UV while running it inside:


----------



## JP Labs

*Re: Scored a Nice 16" Parabolic Reflector. HID or Short Arc? Test Beamshots w/ HID.*



BVH said:


> Great pics. I have only 1 HgXe and that is the 300 Watt Locator. It runs fine from 5 degrees below horizon to vertical. It uses a small fan to recirculate the air within the glass dome. No air is exchanged.
> 
> Today, I did some high voltage wire splicing of my own on the Target Source. I used 5 layers of non-adheasive heat shrink with no issues. My closest distance from + to - is about 5/8".



What specific lamp does your locator use?


----------



## FRITZHID

*Re: Scored a Nice 16" Parabolic Reflector. HID or Short Arc? Test Beamshots w/ HID.*

They use a GE MARC-300/35K projection lamp


----------



## BVH

*Re: Scored a Nice 16" Parabolic Reflector. HID or Short Arc? Test Beamshots w/ HID.*

GE Marc300 EZS to be specific but all Marc 300's use the same quartz envelope and gas fill. I should also mention that the Anode is positioned out front in this application - contrary to almost all my other lights where the Cathode is out front.


----------



## JP Labs

*Re: Scored a Nice 16" Parabolic Reflector. HID or Short Arc? Test Beamshots w/ HID.*



FRITZHID said:


> They use a GE MARC-300/35K projection lamp



OK, thanks to both of you for the info about that lamp. 

As I recall from earlier discussions, these Xe Hg lamps have much more stringent cooling requirements, with both ends needing cooling, and are extreme pressure lamps, with overpressure even when cold, so the cooling needs to be right. Not sure I can pull off using one in my light. What do you guys think, would Xe Hg work for me?

I am going to keep looking for "any position" options I can mount & cool axially in my reflector, and run with my Oriel PS gear, which is DC. 

Osram XBO lamps have similar form factor to the HBO, and they work in any position, so these are one clear option. I initially picked HBO instead of XBO due to HBO having about 4-5x more lumens for same power. Sounded good on paper! 

*Lesson learned: Super high pressure Hg short arc lamps, the Osram HBO variety at least, require you to know, and comply with, the orientation specification. *I wish I hadn't seen conflicting specification, indicating S90 orientation in the one source. I allowed that to persuade me it would work. Now, I know it was bad info.

On the positive side, I should already have achieved a good beacon mode, aiming straight up, with the HBO lamp currently installed. When I get more time, I will get some comparison beamshots for HBO vs the 35W HID I initially used. That will be a big moment for my project. I expect the HBO will absolutely destroy the HID in both beam visibility and collimation. It should have about 30x the arc intensity of the HID. 

Beacon mode (straight up, not a strobe like with LED beacon mode) was one of my main goals, so this would be a partial success. But, the drawback with HBO of not being able to maintain good brightness when aiming at targets on earth is a big disadvantage. So, maybe that is a new piece of info for the CPF community, from my adventure.

I will also try higher amperage on the HBO in horizontal orientation, to see if it will re-stabilize at rated power with more current. But I don't want to do that in the reflector, in case I pop the lamp. It is clearly risky running a lamp outside recommended parameters like that. I will need to devise a test enclosure. Also, from BVH's recent experience destroying a power transistor when a lamp failed in one of his IR illuminators, I suppose I might hurt the PS if an electrode vaporizes and coats the envelope with a dead short of metal. Since the Oriel is current regulated across a broad range of loads, maybe that less of a risk.

Perhaps I should have taken the MHI route instead (used the MSR400SA lamps I originally bought). Those are any-position lamps, but they are AC lamps. Lightsward had suggested some workable HMI lamps and ballasts by Jenbo. These lamps are interchangeable with the MSR lamps I initially planned to use, and I still have one left. New Jenbo ballasts are priced similar to what I spent on the used Oriel gear. Arc length is about 3x as long as the HBO lamp at similar power, but output is 3x higher. I think that would have been a workable solution. But I can't give up on the DC power supply and ignitor, yet. MHI Lumens are impressive, but they do not develop nearly the same arc intensity as a DC short arc lamp. And spending again for a different PS would hurt!

---

Interim Summary (or TL;DR): I now think MHI lamps would have been easier, lighter/more compact electronics, brighter, and similar cost vs the DC SA lamps. But much lower intensity.


----------



## JP Labs

*Re: Scored a Nice 16" Parabolic Reflector. HID or Short Arc? Test Beamshots w/ HID.*

I was uneasy about the conflicting specs for lamp orientation, so I checked the specification for my HBO200W/2 L1 lamp again to see who said what. 

It is the _official Osram site_ which lists the orientation as S90, anode underneath. One would expect Osram to have the correct spec for their lamp. Look at the tab labelled 200W/2 57V (HBO200W/2 L1 variant is rated 57V):
http://www.osram.com/osram_com/products/lamps/specialty-lamps/hbo/hbo/index.jsp

Bulb Connedtion shows S45 for the same lamp. Either this spec is correct, or I am doing something wrong:
http://www.bulbconnection.com/ViewS...ing/Osram_69198_HBO_200_W_2_L1_bulb_item.html


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## JP Labs

*Re: Scored a Nice 16" Parabolic Reflector. HID or Short Arc? Test Beamshots w/ HID.*

Been reading up on XBO lamps today. After hours of reading lamp specs, my effort was rewarded. Not so much by new knowledge, but by a wonderful little bit of humor added by whoever wrote this in-depth technical paper on XBO lamps:
http://web.mit.edu/jhawk/tmp/ENGR_BLTN11.pdf

Under troubleshooting, I found this (p. 45):

_Continuous burning: XBO lamps that do not go out even after the power supply plug has been withdrawn are extremely rare._


:thinking: 
​
I also learned today (some might be a repeat if you can remember the whole thread, I cannot, and didn't go back to check):

The XBO75 and XBO100 lamps are specifically rated for horizontal operation. 150W versions (the biggest I can find, and run with the Oriel) are not. There is a 250W version, don't know yet about it's orientation, out of stock anyway.

The larger lamps may be able to run horizontal as well (has been suggested to me), but with reduced life. That above MIT paper describes why - arc deflection causing uneven electrode wear, and internal convection currents causing electrode deposits to appear on the side of the envelope, which is at the top when horizontal.

These 75W and 100W XBO lamps have much lower efficiency than the HBO lamps. 75W is only 1000 lumens. Compare to 10,000 lumens for my HBO200 and 40,000 lumens for the MSR400 lamp I originally planned to use. 

Aluminum is specifically not recommended for lamp mounting. I suspect this is due to the oxide layer, which could interfere with current flow. I used aluminum. Brass or bronze are recommended. 

Magnetic arc correction is recommended for horizontal operation, to counter convective forces that deflect the arc upwards, even in lamps rated for horizontal use. Magnetic fields from the cables can cause unacceptable arc deflection. I can't see the arc from the side well enough, when it's in the reflector, to check this.

Power leads are recommended to be no longer than 50 cm, to reduce high frequency, high voltage losses. Mine are about 150 cm. I can still strike the arc, on Hg at least, but Xe lamps are a lot harder to start. Could be an issue.

XBO100s list for about $420 apiece, lowest I found was 265! There aren't any on the usual auction site. Hmmm, I'm not spending that much to downgrade output to only 1000 lumens; I don't care how sharply it can focus. That is most of the cost of a proper ballast for my 40k lumen MSR lamp.


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## JP Labs

*Re: Scored a Nice 16" Parabolic Reflector. HID or Short Arc? Test Beamshots w/ HID.*

After several more hours of online research, I have been unable to identify a true short arc lamp with high lumen output that will run vertically and horizontally on the Oriel gear (200W DC rated, 300W absolute limit). HBO series is the only design I can find that 'should' work. I can't find any HBO application data about transitioning from horizontal to vertical to learn from, either. They always call for either one position, or the other, not both. 

So, I'm stumped for alternate lamp choices, beyond the low output 75 and 100W XBO lamps. Are those really the best I can achieve in a true short arc with my gear? I have researched the Hg and Xe types as much as I think is productive.
*
Are there DC powered XeHg lamps around 200-250W that I am overlooking?*

I would still love to try an XBO 100, at least long enough to get beamshots vs the 35W HID to see what extreme intensity vs 3x the lumens can do! But they are so darned expensive. There isn't a single one on eBay. I would need to pay retail. I'll keep an eye out for a deal, maybe even on a used one. I am torn between buying one of these new, or getting a ballast for my MSR400 SA. If I am going to dump a few hundred more dollars into this light, I suspect getting the ballast would be the smarter route.

I did read up on the GE Marc 300/35k lamps. I don't have quite enough power to run one; they need 300W, my Oriel PS overload cutout is set at 300W. It can deliver 12A, so current is not the issue, power is. It would be close, I might be able to run one at 250 or 275W. Not sure it would work. More importantly, these lamps are discontinued, and if I could find one, they only last 25 hours. 25 hours! 
BVH, you have my sympathy and respect; I see now that maintaining your BEAUTIFUL locators must be pretty difficult, with such an unobtanium bulb at their heart! (and the last thing you need is one more guy trying to compete for available lamps).​ 
The HBO lamp would be great, if only it would run horizontally. * I am starting to think (hope?) that the Osram position data is probably accurate, and it should work horizontal, but that I am doing something wrong.* Sylvania engineers clearly know more about this than I do! But it could still be a typo error.

Brainstorming about what that 'doing something wrong' might be, I came up with the following possible issues and tests to verify:


Maybe there is too much convective airflow in my light to maintain temperature.
I can block off all airflow paths and see if it helps. 
 
Maybe lack of magnetic arc stabilization is the problem.
I can play with adding magnets if I can figure out a way to view the arc in operation. I thought about drilling a hole in the reflector, but that seems drastic, and I am afraid I would deform it and wreck it. I'll probably use a mirror on a stick. I would have to violate my 'only run the lamp enclosed' rule, though. Welding mask, gloves, thick jacket.... 
Drawback is that any magnet tuning of arc position to improve horizontal operation will have the opposite affect when vertical, pulling the arc out of position. I might find a balance that works for both. 
 
Maybe the cables are causing a magnetic field that destabilizes the arc.
I can try inverting the whole light in horizontal position, so the cables are at the top instead of the bottom. I can also try relocating the cables themselves. Heck, I guess I should just remove the lamp from the reflector, put it into something smaller and more airtight, and see how it behaves in different positions. 
 
Maybe I just need to crank the current, to maintain power at 250W, no matter how low the voltage sags.
This seems like a bad idea, likely to erode the electrodes. It is my planned last resort, at this time. 
 
The cool temperatures in my shop may simply be preventing the lamp from running at design temperature.
Cool shop temp is only about 10-15C below normal room temperature, and for a lamp that wants to be 1000C, that is a pretty small offset. I don't think this is the problem. 
 
 
So, I did come up with a few things I can try with the HBO lamp. I'm not giving up on it yet. I welcome any other theories about what could be going on!

Have any of you guys ever played with super high pressure Hg short arc lamps like the HBO? Experiences?


I still owe you guys (and myself) beamshots of the HBO200 vs the 35W HID. Hopefully, I will have some evening time without rain or snow this weekend.


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## BVH

*Re: Scored a Nice 16" Parabolic Reflector. HID or Short Arc? Test Beamshots w/ HID.*

This is from the guys at A.R.C.

It is possible if they use a smaller amount/percentage of Hg than is usual in the gas fill blend. This would not be a production lamp.


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## JP Labs

*Re: Scored a Nice 16" Parabolic Reflector. HID or Short Arc? Test Beamshots w/ HID.*



BVH said:


> This is from the guys at A.R.C.
> 
> It is possible if they use a smaller amount/percentage of Hg than is usual in the gas fill blend. This would not be a production lamp.



Sorry, I'm not sure I am comprehending your comment. Do you mean A.R.C. could make a custom lamp to my requirements, that will have proper fill to achieve temperature at whatever power level I need?

If so, I suppose that falls in to the 'if you have to ask' category for me, in terms of acquiring one personally.


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## JP Labs

*Re: Scored a Nice 16" Parabolic Reflector. HID or Short Arc? Test Beamshots w/ HID.*

I experimented with horizontal running today. I can see the arc well enough to tell it was not sharply deflecting upwards. It seems a little more diffuse than in vertical running, but not drastic.

I realized the 3 small rare earth magnets I had used to attach the light shroud might be affecting the arc. I replaced them with Velcro. There did seem to be a small improvement. 

Inverting the light didn't make much if any difference. Neither did moving the cables.

Blocking convection airflow openings didn't make a significant difference, either.

So, on to the last resort. Crank the amps. It takes about 3.3 - 3.4 A to run vertical.

The light will stabilize in horizontal running at 4.6 amps. I ran it like this for about 10 min, after it was already fully warmed up in vertical running. Nothing melted.

This is a breakthrough! I do need to be careful not to aim upwards again without re-setting the current. That will be a minor annoyance. But, it is now apparently functional in any orientation. Note that the manufacturer's spec is only 3.6A, so I am probably using up the lamp life faster than intended. But I'm pretty happy to have found a workaround!!

:twothumbs Woohoo!

I'm off to get a sturdier tripod, and something to lug the power supply and ignitor around in.

There might, perhaps, be an interesting update later tonight.


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## BVH

*Re: Scored a Nice 16" Parabolic Reflector. HID or Short Arc? Test Beamshots w/ HID.*



JP Labs said:


> Sorry, I'm not sure I am comprehending your comment. Do you mean A.R.C. could make a custom lamp to my requirements, that will have proper fill to achieve temperature at whatever power level I need?
> 
> If so, I suppose that falls in to the 'if you have to ask' category for me, in terms of acquiring one personally.



I'm sure ARC can make just about anything but they prefer not to. They were just saying that with less percentage of Hg fill in the blend of an XeHg lamp, a lamps' performance is less susceptible degrading performance at extreme angles of operation.

Also, they have told me in the past that 10% of current/power can be added and subtracted with no affect on the lamp. So maybe you'll lose a little life with a 25% increase.


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## JP Labs

*New Beamshots w/ HBO200 Lamp*

Ok, thanks, I see.

Here's the new base - a construction tripod with spikes to stomp into the ground:




Beamshots:

Weather Underground says cloud ceiling is at 6000 feet tonight.

Panasonic Z50 DMC-FZ200, Night Scenery auto mode. The beam appears roughly the same as viewing by eye. 

It was shooting at ISO1600, f2.8, 1/2 second:















This tree is almost exactly 50 yards, horizontal distance:


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## JP Labs

*Re: New Beamshots w/ HBO200 Lamp*

* Now, for reference, the original 35W HID:* This one is f2.8, 8 sec, ISO100. So, it is same exposure as the HBO shot just below it, but was taken on different night, way out in the dark country::





*HBO200 again, equivalent exposure, but in bright city, tonight:*






* One more of the 35W HID:*
This is one of my favorites so far, even though it was the old lamp - shooting the stars really makes the beam look impressive! This one is ISO1600, f2.8, 8 sec. So, 16x (4 stops) more exposure than the two above shots. Much wider view, from a lot further away, clear, dark sky. That HID really does shoot a nice, long, tight beam: 





I will eventually take real A-B shots. I ran out of time tonight. And, it was freezing out. 

Oh, one more thing. This Oriel power supply is regulates current, not power. While I was taking photos running the HBO horizontal at about 4.4 amps, the lamp voltage crept up while I wasn't watching it (lamp getting hotter). Maybe 5 min time. When I checked the meter, it was pegged! Well over 240 watts. Turned it back down quickly. So, it may seem stable in horizontal, but it isn't, quite. Needs monitoring.

There! Your patience has been rewarded with semi-comparable beamshots of the HID vs a true Short Arc lamp. 2700 ish, HID lumens, vs. 10,000ish HBO lumens.


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## BVH

*Re: New Beamshots w/ HBO200 Lamp*

Very nice shots! Thanks for braving the cold to get them. If I'm remembering correctly, my newer generation 69920 Oriel gives the option of regulating Current OR Watts/power. (Still have not found a reasonably priced ignitor/lamp housing) I'm currently looking to find a 69910 (200-500 Watt) for cheap so I can run 300 Watt and under lamps. The 69920 floors out at 350. I have two very nice ILC 100-500, POT adjustable PS's but they do not seem to be as "beefy" as the Oriels. They are built for the Cermax ceramic body lamps specifically and they sometime balks at igniting conventional SA lamps. Once running, they work fine.


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## JP Labs

*Re: New Beamshots w/ HBO200 Lamp*

Power regulation would be really handy! I just double-checked the manual for my 68805. It regulates current to a user set value, with no option to regualte power. Interestingly, it DOES have an output power limit, but the latter is not user adjustable. It's factory set at 300W. If I were more knowledgeable, or had the calibration documentation, perhaps I could reset that at 200W, crank the amps, and run on the safety power limit all the time. The remote connector on the PS has power out and current control signals, so an external controller should be feasible, too.

Or, if I had a 300W lamp, it should theoretically be impossible to overpower it. I've never seen a 300W Hg SA lamp, and only one 250W. The ceramic Xe SA lamps seem to come in 300W.

Short excerpt from the Oriel 68805 user manual here. (Credit Oriel Corporation):
_Arc lamp sources will be operated in constant current mode by the Oriel Model 68805 power supply
with the output voltage being dependent on the arc lamp’s impedance. The Oriel Model 68805 power
supply will provide a constant current of up to 11 amperes with a load voltage range of 0 to 100 volts.
A power limit, which limits the product of output voltage and current to 300 watts, protects the unit
from output overloads. A constant current power supply regulates current even into a short circuit,
and themodel 68805 is safely limited to 12 amperes or 300 watts._​
I'm looking around for 300W Hg lamps now. I did find several brand new ARC 200W Hg lamps for auction at a mere $25 each. They look a lot like my HBO, but seem to have a sharp, thin protrusion on the Cathode, whereas my HBO cathode tip is shaped about like it's fatter Anode. I may buy one as a spare.


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## JP Labs

*Re: New Beamshots w/ HBO200 Lamp*

Thinking about the testing I did last night...some not unexpected, but interesting observations:

The effect of focus was greater with the SA lamp. Meaning that refocusing for every target distance made a big improvement in the shape of the spot. With the HID, focus was less critical. 

I could not get a perfect, round, concentric pattern in any case. It had a few minor lobes - 3 skinny ones at roughly 120 degrees apart, actually. This can be best seen in the above cloud spot photo, post 131, 3rd pic. 

The SA beam seems more tenuous. By that, I mean 'stringy' looking, with really bright regions, and dim regions, like the pictures of stellar Nebula. The HID beam seems to have more uniform density. Even de-focusing the SA lamp didn't smooth it out like that HID beam, it just widened the pattern. The central core of the focused beam is more intense and better defined with the SA.

I know that a smaller arc requires better optics. I suspect that I am seeing dimensional variation in my reflector which was less evident with the larger HID arc. I also suspect that this would be worse with a really compact arc, such as with the HBO100 lamp. I may be near the practical limit for arc compactness on this reflector? 

While fabricating the reflector frame, I had the reflector supported on 3 points, 120 degrees apart, then tack welded the frame together. I was as gentle as I could be, but there may have been thermal stress induced by welding 1/2 inch from the reflector at these points. I might have induced a slight tri-lobed deformity in the reflector, hence the beam pattern. Just guessing...

Spill from the SA lamp makes RAZOR sharp shadows. Neat.

That $35, 5' tall, collapsible tripod was a great deal, too. It is really firmly planted in the grass, with no real risk of the lamp falling. Sale 50% off at Lowes for a few more weeks. If anybody needs a stable outdoor lamp mount, and doesn't mind having to adapt something to fit the cast aluminum tripod head, think about grabbing one. 

I'm going to design and perhaps build a travel case for the power gear today.


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## JP Labs

*Re: New Beamshots w/ HBO200 Lamp*

OK, I got a crate built for the power gear. The PS does not have illuminated controls, so I put 2 sets of LED strip lights inside. 36 LEDs with 200 mA @12.5V. WAY too bright, I need to dial 'em down.

The PS is angled for easy viewing, and recessed for protection. Ignitor on top, power strip above that in back. Storage compartment on bottom. The lid is a trap door. Front will get 2 more doors. There is foam around the air exits on the sides to prevent recirculation to the fan inlet:









This shows how bright they are - those are warm white rope lights along the pool fence:


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## JP Labs

*Re: New Beamshots w/ HBO200 Lamp*

Here is another batch of beamshots from tonight. It's about 30F, cold, dry air. There is a bright bonfire near the light.


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## JP Labs

*Re: New Beamshots w/ HBO200 Lamp*

Finally, here are 3 shots with bracketed exposure, to show how it affects the look of the beam. First one is normal, then +2 and +3 stops overexposed:












There, I bet that's plenty. I wish I had further targets. After I test out the 12V inverter, if that works, I will be mobile and can find a better spot.


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## BVH

*Re: New Beamshots w/ HBO200 Lamp*

Have you determined from how far away you can see the beam clearly enough for it to be a usable beacon as your original intention was?


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## JP Labs

*Re: New Beamshots w/ HBO200 Lamp*



BVH said:


> Have you determined from how far away you can see the beam clearly enough for it to be a usable beacon as your original intention was?



In the cold air, with the fire burning and bright exterior house lights on behind that, it was pretty faint from 100 paces away. The HID was just as visible from a twice that far, but in a very dark area with higher humidity. So, it varies, a lot. I'll need more experience and testing to give a more accurate assessment.


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## JP Labs

*Re: New Beamshots w/ HBO200 Lamp*

Tonight it is foggy. "Hmm......I bet the searchlight will look cool", thinks myself.





















Yep, it does. Fun session.


As you can see, humidity makes a huge difference. The beam doesn't go NEARLY as far as it would on a clear night, but boy-oh-boy, can you see it! It can completely drown out the city glow tonight. It casts a glow of it's own in the whole yard, with the beam throwing so much light off to the sides. It's like swinging a gigantic fluorescent lamp around.

Yes, I did make the zzzzoooooommmsssshhh light sabre sound in my head while waving it around the sky.






Storage configuration:


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## JP Labs

*Re: New Beamshots w/ HBO200 Lamp*

Just a quick update to follow up on if this can be run on a 12V inverter. So far, no. I've tried up to a 750W continuous, 1500W peak inverter, but it cuts out as soon as the SA power supply is turned on. It cycles on/off but won't let the PS wake up. I suspect there is a high inrush current in the power supply that exceeds the 1500W burst power available from the inverter.

I have a Variac, and I considered using that between the inverter and the SA power supply, to bring the voltage up slowly to avoid the inrush peak current. But I'm worried about hurting the power supply by undervolting it, so I haven't tried that.


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## PolarLi

*Re: New Beamshots w/ HBO200 Lamp*

Have you tried the inverter on other power hungry equipment?


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## BVH

*Re: New Beamshots w/ HBO200 Lamp*

I re-read some of this thread and just remembered something. If I have a brain lapse and try to turn on my Oriel 1000 Watt PS from my power strip on the bench which is fed from a breaker box GFI breaker, it pops the breaker and I notice a slight dimming of the garage lights. I'm not talking about powering up a lamp - but just turning the PS on with no load. When powered from any other circuit, there are zero issues. I realize your PS produces significantly less output but I would guess it has a similar effect on your inverter.


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## LightSward

*Re: New Beamshots w/ HBO200 Lamp*

Awesome Light. Keep up the awesome work.


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## louieatienza

*Re: New Beamshots w/ HBO200 Lamp*

All I can say is WOW.... building a smallish one right now as a first project... this is so awesome!


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