# 1,000 Watt Marconi Radar Systems Military Short Arc Searchlights



## BVH (Oct 12, 2012)

Newest acquisition. I spotted these behemoths a couple weeks ago and stayed with the bidding process until I snagged these powerful military Short Arcs. While they may remotely resemble the MegaRay, the light with the 90 degree mirror weighs 72 lbs and the straight output light weighs 60 lbs. The optic you see in front of the straight output configuration light is approx. 5.75" to give some idea of scale. I am expecting them to arrive any minute so some of my description may change as I confirm things. I brought them all the way over from North Wales, UK. Can you believe it....They were picked up on Tuesday morning and are almost here.

I've not been able to determine what they were prototyped for (These are Prototypes #2 and #3) but I would suspect some type of aircraft. Not that I am all that familiar with all military lighting, but I have never seen nor heard of anything like these so I have a feeling they never made "production". They don't really resemble any helicopter light I've seen so maybe they were developed for some type of fixed wing reconnaissance aircraft. No hits on Google other than the sales thread and a forum they were on before. They were made by Marconi Radar Systems, Ltd before they were absorbed by BAE so that puts these lights at somewhere around 1985 or earlier. Does anyone know if visible light is ever used to run or test radar systems? I have wondered if they are somehow related to radar systems. The seller had them for a couple of decades after buying them at a MOD military auction in 1991. They both function as designed and built. The second light has a rotating mirror in the head to deflect the light 90 degrees, other than that, they are the same. The switch box provides knobs for dimming and one to rotate the deflection mirror. Each one has an internal shutter so the light can remain on without any visible light being transmitted. Sort of like the VSS-3a and how it turns on in infrared mode so as not to give away its position inadvertently. The seller states that the input fuse is rated at 75 Amps and the system runs on 28 Volts so knocking off 1/3 of the power (as a guess), these could be 1500 Watt Short Arcs. I don't know beam spread at this point either but am hoping for 2 degrees max and better yet, 1 to 1.5 degrees.

At some point, I am going to try to get to my test range for comparison shots. However, I don't want to repeat my "tank lights" episode from years back in which my 2.2KW VSS-1 "tangled" with the local Police departments' 1.6KW NightSun. There are no PD choppers here so I'll just have to worry about the local patrol vehicles. To power them at the range, I'll need my 4.5KW, 240 Volt generator and the Lorain 29 Volt, 100 Amps Rectifier. I think the 240V/16.5 Amps from the genny will be enough but will run the Lorain in the field but will try it at home from the house 240V/30 Amp circuit first to measure. That's a lot of heavy stuff to handle so the beam shots won't be easy to get. And the genny noise plus what I expect to be an impressive beam will probably generate calls.









Cooling fan intake or exhaust, not sure yet







Separate Power Supply







Be Careful!







Switch Box







Front View







Profile







Right Angle device







OEM Crates







The Pair







The light is a full third larger than I had imagined. It is a monster but I don't think it's 80 lbs. Guessing 60 but will weight it later.

Fire Foxes 3 and typical Kleenex box with tape measure.







I just had to take the front lens off to see inside. I'm very surprised. The orifice the light is emitted from is about 1/4" to 5/16" in diameter. Makes me think this is a laser. It's kind of scary looking in there. But then it hits a Plano Convex lens and is dispersed. How much, I don't know. I've got a lot to look at before I fire one up. And then I don't want to melt anything I'm aiming at so will break out a leftover piece of 3/4" granite slab.


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## BVH (Oct 12, 2012)

*Re: Right Place At The Right Time - Vers. 2.0*

A few more pics. Upon removal of the ignitor cover, I noticed that there is white "goop" over the surface of the main ignition coil. However, on all other coils like this that I have seen, the goop or other insulation is hard. This stuff looks and feels like it has turned to the consistency of Thermal Compound and the oil base has partially separated from the solid material. There is an oily film on many of the components and on the bottom and side of the ignitor housing. Anyone ever seen this?

Ignitor Cover







Ignitor Coil with Goop fallen off







More Goop where I don't think it should be - probably from shipping







More Goop thrown around







Warning







Ignitor identifier







Cooling Fan







Ignitor Cover with Goop


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## FRITZHID (Oct 12, 2012)

*Re: Right Place At The Right Time - Vers. 2.0*

incredible find Bob!!!!:twothumbs I'm jealous as hell! Lol
interesting with such a small light output orifice, I'm very curious!


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## The_Driver (Oct 13, 2012)

*Re: Right Place At The Right Time - Vers. 2.0*

I love following you story-type monster-light-threads :twothumbs


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## BVH (Oct 13, 2012)

*Re: Right Place At The Right Time - Vers. 2.0*

Thanks Driver!

More pics of the lamp and surrounding area

Finned "Snout" removed to reveal lamp and shutter device. The burn impression on the shutter reveals the beam to be about 5/8" in diameter as it hits the shutter.







There's a small motor that pivots the shutter out of the beams' path. The reflector is obviously an Elliptical as it's harnessed all output into the 5/8" diameter beam at the shutter and then after traveling another inch or so, it passes thru the .300" hole behind the shutter. From there, it has to travel about another 6" to hit the Convex lens where it is collected, diverged and sent out tightly collimated at about the size of the 5.75" lens according to the seller. 







Front of the light, snout removed showing lamp support. One of the two bolts on the right was nearly falling out of the hole.







Lamp Close-up. Chamber looks to be about 1 5/8" in diameter. I didn't notice the "0.8" and smaller text in the reflector while taking the pic. I need to go back and see where it's coming from. Only markings on the front base so far are "49". I still don't know the power level of the light. I'll have to take readings with the ignitor cover off at some point. checking and setting focus will be a time-consuming task. The snout needs to be removed for each movement.







Much as I want to, I've decided to not remove the lamp until I have run the light just in-case something happens during removal and re-installation and I want to get the Volts and amps at the bulb so I know the power level and can get a new bulb made if the need arises.


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## BVH (Oct 15, 2012)

*Re: Right Place At The Right Time - Vers. 2.0*

Just some guessing of output power. Based on the strip resistor in the power supply, the lamps running Voltage will be between 20.2 and 20.8. after start-up and boost. They have tapped the strip at 3 points and each tap lands on its own terminal which is marked with a Voltage range. The cable directly out to the ignitor and then to the Anode is on the "20.2V - 20.8V" terminal. My second guess is that the Amperage draw will be somewhere around 66% of the 75 Amp input fuse rating - so 49 Amps. 20.5 x's 49 = 1004 Watts. Once I finish re-insulating the 45KV ignition coil, I'll be able to fire it up and verify the numbers. I'm hoping for more than 1000 but logic tells me it will be right at 1000 Watts. Changed the title to reflect my guess. Doing lots of cleaning and polishing while I wait for the multiple layers of liquid electrical tape to fully cure on the coil. Maybe done by Wednesday.


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## FRITZHID (Oct 16, 2012)

*Re: Right Place At The Right Time - Vers. 2.0*

:twothumbs


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## nealitc (Oct 16, 2012)

*Re: 1,000 Watt Military Short Arc Behemoths*

Neat! Thanks for pics and data. Glad someone here got them, I considered bidding but shipping cost looked huge from UK (you obviously sprung for air freight).
For power supply, just fired up my AN/VSS-3 with a Mean Well RSP-1500-27 switch mode up to 56A output and will run on 120V, $335 + tax and shipping from PowerGate. Might work for you.


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## BVH (Oct 16, 2012)

*Re: 1,000 Watt Military Short Arc Behemoths*

I mentioned in your VSS-3 thread about member Modamag's 2 remaining Lorain 29V/100 Amp rectifiers that will run off 120V. $150 each. He's in your area so you could pick one up, no shipping.


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## Echo63 (Oct 16, 2012)

*Re: 1,000 Watt Military Short Arc Behemoths*

looking forward to seeing this thing fired up.

i dont think i will ever get anything bigger/badder/brighter than a Maxabeam, but to see one of these big beasts (60"CA, VSS3, Megaray, Locator etc) in action would be awesome


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## Zephrus (Oct 17, 2012)

*Re: 1,000 Watt Military Short Arc Behemoths*

Hey BVH nice lights and great find! Having been a pilot for a while and from my time at Fort Rucker, my best guess would be that these were design to be some sort of quick-deploy beacon lights for military aircraft. What leads me to this conclusion is the rotating (or oscillating) mirror head on the one light. There was most likely a rotator also meant for the second which got lost along the way. I think that, with the rotator attached and operating, the beam profile and divergence will tell us more. Typically, aircraft beacons will have a slight upward angle of a few degrees as well as a certain spread, and will be configured such that the lower portion of the beam is near parallel with the ground or diverging about a degree from it. 

When you get these babies fired up it should be more telling. Check the mirror, is it absolutely flat or does it have even the slightest convex shape to it? It may be hard to tell on visual inspection but will be much more obvious when operating. Also when operating, see if the beam really is deflected 90 degrees of if there is any upward angle along with a certain amount of divergence. Does the mirror actually rotate or is it a side-to-side oscillation? How fast is the rotation or oscillation? I was also noting the converging mount holes in the flanges on the light without the rotator head... can't really see the other side but this may be another clue. It does say "searchlight starter" on the power supply but that may not be very telling if it was a "generic" light starter used in other apparatus as well. Being prototypes this really has me curious :thinking:


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## BVH (Oct 17, 2012)

*Re: 1,000 Watt Military Short Arc Behemoths*

Thanks for the thoughts, Zep. I've spoken to the Advanced Radiation Corp (ARC) guys a few times on lamp orientation. It is always best to orient the bulb so that when a light is in normal operation, the Anode is straight up. This is because all the brute forces of the flame are directed at the large Anode electrode - which is designed to take the heat and force. Cermax bulbs come with a warning not to operate them above 45 degrees above the horizon. This is because the thin Cathode is in front. Point it up too much and the flame will be blown back against it and damage occurs rapidly. This is the same configuration used in these lights. The Cathode is in front. If the lights are pointed up, the bulbs would most likely expire quickly. I can only conclude that they are made to run horizontal (an acceptable compromise) or possibly even run facing down - best for the lamp. The Anode in the VSS-1 was straight up. Perfect for the bulb since the light was used horizontally, not much up or down. My 600 watt helicopter minigun light has its' Anode in the rear so as it's pointing down, the Anode is up. The VSS-3 has its' bulb oriented horizontal - the compromise. So these certainly could have been airborn using the compromise orientation. But why the 90 degree head?

The non-90 degree light has a cast alum lens holder that finishes it off in front so the lights were made to be finished off either way - straight or 90 degree. Either end piece will go on either light - the snout and its' mounting flange are the same on both lights. The rotational motor wiring exists in both lights.

I did learn a tid bit today from an acquaintance. He knows someone who worked supplying a few short arc bulbs to a military contractor here in the U.S. many years ago. It was secret at the time. The light was being developed to defeat some type of Radar system. It was heavy in the U.V. output and could be variably pulsed and was approximately 1KW. I don't see any pulsing facilities or components (not that I would necessarily recognize such components) but it is interesting that Marconi Radar Systems business was all about designing and building Radar systems. Who better to develop a Radar defeating device that themselves?

Final coat of Liquid electrical tape applied today. A good 24 hours to dry and maybe tomorrow or Friday might be fire-up eve. Not sure about the beam shots though. Gotta think about how to do it descretely.


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## BVH (Oct 19, 2012)

*Re: 1,000 Watt Military Short Arc Behemoths*

Grabbed a quick, down and dirty beam shot out of the garage. Just kind of a "it works" shot. Unfortunately there is no frame of reference beyond the gate. The next surface for light to hit is 4,800 feet away and fog was starting to obscure it. So at this point, I don't know how it looks on typical 350 yrd, 900 yrd and 1,100 yrd targets I usually shoot at. Not much else I can do given the length of my power supply cables. Might try my tired 110 Amp SLA's to see if I can take the setup to the range one night. Kind of looks like a natural gas flame.

It's a 1000 Watt light, give or take. Running about 19.5 Volts and 49 Amps to the bulb, all other components such as fans etc are out of the calculation. So it's currently running at about 955 Watts.

The end of my Cul-de-Sac is just to the left of the beam and I made sure that all neighbors were in for the night and that no lookie-loos were coming before I ran it. Neighbors across the street were aware and promised not to look at the source. Even with all this, I was very nervous about lighting it off.

If you love the sound of a gas turbine winding up, you'd love to hear the start up of the power supply and light cooling fans. The closest I've ever heard! Man, it sounds WAY COOL!


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## FRITZHID (Oct 20, 2012)

*Re: 1,000 Watt Military Short Arc Behemoths*

Look'n good bob! Glad to see you got at least one of them fired up!
Seems like a damn bright beam, but is it me or just the photo, that makes it like its weighed heavy to the upper right? Can't wait to see how the distance shots compare! Wtg bud! Congrats


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## The_Driver (Oct 20, 2012)

*Re: 1,000 Watt Military Short Arc Behemoths*



BVH said:


> Grabbed a quick, down and dirty beam shot out of the garage. Just kind of a "it works" shot. Unfortunately there is no frame of reference beyond the gate. The next surface for light to hit is 4,800 feet away and fog was starting to obscure it. So at this point, I don't know how it looks on typical 350 yrd, 900 yrd and 1,100 yrd targets I usually shoot at. Not much else I can do given the length of my power supply cables. Might try my tired 110 Amp SLA's to see if I can take the setup to the range one night. Kind of looks like a natural gas flame.
> 
> 
> It's a 1000 Watt light, give or take. Running about 19.5 Volts and 49 Amps to the bulb, all other components such as fans etc are out of the calculation. So it's currently running at about 955 Watts.
> ...


Very cool lovecpf
How about a video of the startup process?


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## BVH (Oct 20, 2012)

*Re: 1,000 Watt Military Short Arc Behemoths*

Turn the volume WAAAY up!




By the way, the searchlight is not dimmable. The "Dim" knob on the switch box is for dimming the switch box "Shutter Open" and "Lamp On" pilot lamps.

I received 7 cables with the lights. Each cable is sheathed in a fine brass/bronze flexible weave material. I'll bet each cable cost between $300 and $500 to manufacturer.

When warmed up, total Amp draw is about 57 including the fans. My 100 Amp Lorain rectifier acts as though it's not even turned on. There is no Voltage sag at all. 28.0 when idle and 28.0 when powering the load. What a deal at $150! And as a bonus, there is no cooling fan so no useless noise. It has massive heat sinks on the back side.


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## The_Driver (Oct 20, 2012)

*Re: 1,000 Watt Military Short Arc Behemoths*

Thank you very much for the cool video 

Thats louder than I though it would be, your description sound about right though 

I do think the noise would be somewhat prohibitive when using the light anywhere...


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## snakeplissken83 (Oct 20, 2012)

*Re: 1,000 Watt Military Short Arc Behemoths*

Marconi is part of BAE now. I used to work for them at the Rochester factory (Rochester in Kent, not Rochester in New York). I cant actually say what they made there (official secrets act) but suffice to say they were THROWING OUT loads of cool stuff...I expect they may have had some stuff similar to what you've got there. If only i'd been into lights back then!


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## BVH (Oct 20, 2012)

*Re: 1,000 Watt Military Short Arc Behemoths*

Thanks snake. Might you know of anyone who may have worked at the Leicester plant who might know something about these?

Driver your right about the noise being loud for a light. But it sure sounds great and adds to the mystic of the lights. These certainly won't be "casual use" lights with all the equipment needed to run them away from a 240 Volt outlet. I could do it now but it would take my 175 lb, 4.5KW generator, the 85 lb Lorain and its' #4 cables, 30 lbs of hook-up cables, 55 lb power supply and 70 lb light. I'd love to spring for some high Amp Hour, custom 7-cell SLA's but they are way too much money for very occasional use.


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## Walterk (Oct 20, 2012)

*Re: 1,000 Watt Military Short Arc Behemoths*

What do you do in your spare time? Googling and ebaying on 'prototype searchlight' ?!
Congrats, interesting thing.

Would have thought it was for optical communication..say over the Street of gibralter or over the Berlin wall.
Is the some kind of shutter inside? Or only the oscillating mirror?


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## BVH (Oct 20, 2012)

*Re: 1,000 Watt Military Short Arc Behemoths*

Post #5, pics 1 & 2 show the shutter in-place and moved sideways by hand. It is solenoid controlled and is instant. I do spend some fair amount of time on Ebay!



Walterk said:


> What do you do in your spare time? Googling and ebaying on 'prototype searchlight' ?!
> Congrats, interesting thing.
> 
> Would have thought it was for optical communication..say over the Street of gibralter or over the Berlin wall.
> Is the some kind of shutter inside? Or only the oscillating mirror?


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## FRITZHID (Oct 20, 2012)

*Re: 1,000 Watt Military Short Arc Behemoths*

Jesus bob! Good thing that lamp weighs so much, it sounds like it could hit 30,000 ft, and I don't mean with a beam! Lol
Hope you have ear plugs!


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## Echo63 (Oct 20, 2012)

*Re: 1,000 Watt Military Short Arc Behemoths*

That thing sounds awesome as it starts up !.

Given that it has a shutter, is it possible it's a communication device ? For sending morse code ?

Actually thinking about it, it's probably way to bright to use at any range where the curvature of the earth wouldnt interfere


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## BravoKilo (Oct 20, 2012)

*Re: 1,000 Watt Military Short Arc Behemoths*

Bob, Even my wife appreciated that power supply and lamp wind-up!!! Nice video!!!!


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## BVH (Oct 20, 2012)

*Re: 1,000 Watt Military Short Arc Behemoths*

All the toggle switches in the switch box are ultra stiff to operate. A Morse Code operator would not last an hour toggling the switch.  The shutter permits the light to be "turned on and off" without having to constantly re-strike it.

The light without the 90 degree mirror is not functioning. It's blowing the 10 Amp fuse#2 (FS2) in the switch box. This happens by simply flipping the "Searchlight On" toggle switch to the "On" position. The fuse is in-line and ahead of the ignition toggle switch so I can't even try to ignite the lamp (well, I can, but nothing happens ) . The fans run and I think there is "potential power" to the bulb (but I need to confirm this). This is the light with the ignition coil that I re-insulated. Since there has never been an ignition pulse to the coil since I received it (because the fuse was blown when I checked it out before operating it), I do not believe it's anything I did. I simply removed the coil, re-insulated it and re-installed it. I've ruled out the Power Supply as neither PS would fire it up (neither of the 2 switch boxes too). Fritz, when life settles down for you, I'd like to pick your brain for trouble shooting procedures.

Power Supply #1 also has an issue, although it works powering up the good light. It wasn't until I powered the good light with PS#2 that I was rewarded with my gas turbine melody. PS#1 must have a low Voltage issue supplying the PS fan and the light fan because they run at a much, much lower speed as compared to running with PS#2. No jet whine!! And airflow is greatly reduced. At the same time though, it is providing full Voltage and current to the lamp circuit. I have not had the time to find where the circuits are common and branch off from each other to begin trouble shooting.



Echo63 said:


> Given that it has a shutter, is it possible it's a communication device ? For sending morse code ?


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## FRITZHID (Oct 21, 2012)

Will do bob, should be arriving in FL in a few hrs


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## BVH (Oct 21, 2012)

I just pointed the seller to this thread. He pointed out that my Lorain Rectifier power supply is a Marconi product. How appropriate to run my Marconi Lights with a Marconi power supply.


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## kuna (Oct 22, 2012)

Man that startup does sound awesome lmao. I was waiting for that piece of wood to start smoking :d You should take some measurements on the cp of this thing im sure it would be up there


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## nealitc (Oct 25, 2012)

*Re: 1,000 Watt Military Short Arc Behemoths*

Nice! Surprised cooling fan does not stay on for a few after lamp shutdown.


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## BVH (Oct 25, 2012)

*Re: 1,000 Watt Military Short Arc Behemoths*



nealitc said:


> Nice! Surprised cooling fan does not stay on for a few after lamp shutdown.



It is possible to do if I use the "Emergency Overide" toggle. It kills the lamp but runs all the fans. That's how I would routinely do it when running them....it...if I could. What I have has pretty much turned out to be one good set and one 'parts spares" set. Light 1 works as designed and built. Power supply 1 works mostly as designed. For some reason, it signals the "Lamp On" pilot light full time, whether or not the lamp is lit. It also automatically, with a slight time delay, closes the main relay such that the emergency Overide toggle will not disengage it to shut down the lamp and leave the fans running. Other than that, it is good to go. I just do a normal shut down and then after a few seconds, turn the searchlight on again for a few minutes for cool down.

Light 2 does not ignite. The 10 amp fuse associated with the ignition switch blows the moment the "Searchlight On" switch is closed so there is no chance to try to ignite it. Power Supply 2 performs all functions normally with the exception of feeding all 3 fans (2 in the light -external heat exchanger fan and internal heat exchanger fan) with about 33% of their needed Voltage so instead of turning 6,000 RPM, they turn at about 2,000 with a huge resulting reduction in cooling air. So much so that I won't use it.

Someone more knowledgeable in electronics troubleshooting could probably figure all these issues out with not much trouble but I don't have the knowledge. I did some preliminary on the light but it's beyond me. Also did some preliminary on the PS 2 but could not get it. In looking at both PS's, there are subtle differences in wiring and on one of the 2 PC boards so it's not as though I can compare readings directly to one another. They are prototypes and so I would expect the development team to have tried different things with different lights. Everything points to there having been 3 protos. 001 - 003. I have lights 2 and 3 and Power supplies 1 and 2. I have cable sets for all 3 minus the 3rd cable from the light to the PS. However, I am totally ecstatic just to have got them, working or not!

I just need to figure out what I'm going to get to power the PS "in the field" so I can get some test range shots. Ideally, I'd like to get one of those "racing" 14V/7-cell AGM's and a matching 12V/6-cell so I can Series them for 27.3 Volts. Or if I'm brave, two of the 7-cell units for 29.4. One drawback is that they are only 50-Amp Hour rated. And it gives me some concern because it's not as though the entire 60 Amp load is placed on the power supply all at once such that I would would have enough Voltage sag to get back down to 28 or so. Before I can ignite the lamp, the fans circuit and the circuit for all the "potential" lamp power are both energized with the "Searchlight On" toggle, which draws only 7 Amps so that 29.4V would be hitting pretty much every component in the PS and light.

I've got to schedule a trip up to ARC so that the corrosion on the Cathode lamp base and the Cathode power connection braided cable on Light 1 can be removed and a new connection cable welded onto the base. Even though I have a "spare" lamp in the 2nd light, I might just have a new one made to keep.

Just from the brief beam shot event, I have a feeling that my beam angle is going to be in the 3-4 degree range. It seemed to "cone out" more than my 2 degree Megaray. But that was just a quick impression on a foggy night so I could be wrong. I need to be able to step 100 feet away to the side on a long distance shot so I can see what the spot actually looks like on terrain.

I've got both units all tucked away in their beds for now. I should be getting my new 600 Watt lamp for the M-134 Minigun helicopter light soon and I need to do some work on the electrical connector and build a cable to have ready for when it arrives.


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## Patriot (Oct 30, 2012)

*Re: 1,000 Watt Military Short Arc Behemoths*

Bob, you make the most extraordinary finds man! The video with the sound demo was just amazing! Great read too.


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## BVH (Oct 30, 2012)

*Re: 1,000 Watt Military Short Arc Behemoths*

Thanks Patriot! Good to see you around here! It's been a while. There's nothing like military hardware!


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## BVH (Nov 28, 2012)

*Re: 1,000 Watt Military Short Arc Behemoths*

Well, finally got brave and suited up to remove one of the lamps in one of the lights. Here's some pics. I, at first thought that the threaded assembly screwed into the front spider was for focusing the lamp within the reflector. And then I wondered how to perform a compound focusing procedure because in addition to focusing the lamp within the reflector, I would think that the final pinpoint of light coming from the elliptical reflector would have to just precisely strike the back of the optical lens. However, for this last description, there is no provision for adjusting any of the components involved. And today, I discovered (unless I am missing something obvious) that there is no provision for focusing the lamp within the reflector. Hopefully, you can follow along below with the pics.

The lamp is supported on the Anode end (back end) by a tapered, fixed mounted stud that mates into the tapered hole in the lamp base. The 8 brass fingers (like a Maxabeam but larger) help guide it onto the stud during insertion and they are also the electrical contact as is the stud, I believe. You can see the stud at the back of the pic showing the 8 fingers. It doesn’t look tapered in the pic but it’s about a 45 degree taper. The lamp is supported on the Cathode end (front) similarly. The tapered hole in the Cathode base end is the same as that in the anode end and you can see the rounded/tapered spring-loaded brass plunger that it rides onto. So basically, the lamp rides between two tapered pins. So unless I’m missing something, the light is not focusable – which I find almost impossible to believe. The Anode tapered stud is fixed and the Anode base sits tightly against it due to the spring loaded pressure exerted by the front brass plunger. Even with the plunger housing completely screwed into the spider, there is still a lot of spring tension pushing the bulb onto the Anode tapered stud. I think the spring tension allows for expansion and contraction of the lamp? By the way the reflector is not made to be move either. So, somebody show me a way to focus-move the lamp. But how can it move if it is designed to ride firm against the back tapered pin?

The lamp:








The gap is about 2mm and looks like some of the Anode has been melted at some point.







If you look close above the Anode electrode, you'll see some quartz chips floating around in the arc chamber







The tapered hole in the Anode (rear) base







The fixed tapered stud and fingers in the back of the reflector







The tapered hole in the Cathode (front) base







The brass plunger and aluminum housing dis-assembled







The brass plunger inserted into the aluminum housing that screws into the spider. I originally thought the aluminum housing screwed in and out for focusing.
Housing screwed out







Housing screwed in






The spider hinged shut







Bottom line on focusing. If the fixed tapered pin in the back of the reflector cannot move in and out (it cannot) and the tapered lamp base hole is designed to ride firmly on the pin (looks like it is) then there is no way to move the lamp in or out for focusing. Anyone see what I might be missing?


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## Johnny47 (Nov 28, 2012)

*Re: 1,000 Watt Military Short Arc Behemoths*



nealitc said:


> Nice! Surprised cooling fan does not stay on for a few after lamp shutdown.



I believe you have obtained some tvs-3 search lights with parts and accessories. I have 5 lights on trailers with nothing else. I would like to know more about them as well as there safety for use, have you operated any ? would you sell any cables and a part or maintence set and or any bulbs? I have no idea what I need for now. I do have access to a 400 cycle 60kw generator. If I wanted to use for any promotions at all, would you have any suggestions as to bulb and gen set useage? JOHN KRUESEL /ROCHESTER, MN.


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## BVH (Nov 28, 2012)

*Re: 1,000 Watt Military Short Arc Behemoths*



Johnny47 said:


> I believe you have obtained some tvs-3 search lights with parts and accessories. I have 5 lights on trailers with nothing else. I would like to know more about them as well as there safety for use, have you operated any ? would you sell any cables and a part or maintence set and or any bulbs? I have no idea what I need for now. I do have access to a 400 cycle 60kw generator. If I wanted to use for any promotions at all, would you have any suggestions as to bulb and gen set useage? JOHN KRUESEL /ROCHESTER, MN.



You probably want Nealitc in this thread: http://www.candlepowerforums.com/vb/showthread.php?348441-AN-TVS-3-project I don't have an AN/TVS-3


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## FRITZHID (Nov 29, 2012)

*Re: 1,000 Watt Military Short Arc Behemoths*

perhaps there is a focusing mechanism for the reflector?


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## get-lit (Nov 30, 2012)

*Re: 1,000 Watt Military Short Arc Behemoths*



BVH said:


> The gap is about 2mm and looks like some of the Anode has been melted at some point.
> 
> 
> 
> ...



Nearly catostrophic I'd say. Not sure but it appears the lamp was supposed to be operated in a vertical orientation, or the anode was not getting enough cooling. It's primary heat source.


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## BVH (Nov 30, 2012)

*Re: 1,000 Watt Military Short Arc Behemoths*

Since these are prototype lights and there is no name or usable ID on the lamp itself, I would guess they were made specific for this light which _*MAY*_ be vertical or _*may *_be horizontal, not sure since I cannot get any info on what they were used for and on. But you may very well be correct in that one of the power supplies is not providing proper Voltage to the cooling fans on either light and the result is a very much slower fan speed that could have been the cause of the meltdown. But I am curious as to why the melting did not occur at the first thinner "ring" towards the Anode tip where it would be hotter versus the second thinner ring?


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## get-lit (Nov 30, 2012)

*Re: 1,000 Watt Military Short Arc Behemoths*

That is odd, the hottest point is at the leading surface and it should have melted there first. The anode is pure tungsten, and is the most difficult part to manufacture, maybe an impurity got into the anode during manufacture. But I'm thinking maybe it's supposed to be orientated vertically when in operation, and when it was operated horizontally, maybe too much heat accumulated on the top side of the anode. Any idea if that happened to be the top side when it was powered up?


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## sven_m (Nov 30, 2012)

*Re: 1,000 Watt Military Short Arc Behemoths*

Or what about some mirror having focused back light to this point of the surface, e.g. byrunning the bulb accidentally in a configuration/position it's not intended to be.


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## get-lit (Nov 30, 2012)

*Re: 1,000 Watt Military Short Arc Behemoths*

Good consideration but at the very most that lamp outputs 150W of total actual light, so even if a ton of light, say 25% of the output were reflected directly back onto the cathode, that would only be an additional 37.5W of heat which is minimal compared to the 800-900W of heat it's made to deal with. That's at most 5% additional heat on the cathode, and cathode heat tolerance is typically 50% or greater. Now if the light were directed to other components, such as the nickel lamp base, that would cause discoloration and eventually blackening of the Nickel but still nothing to the extent of this damage.


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## BVH (Nov 30, 2012)

*Re: 1,000 Watt Military Short Arc Behemoths*

Let me say that these lamps are the bottom of the barrel from those I have seen in my CPF HID "career". They definitely are NOT production and were probably "hand-made" without the aid of much tooling and jigs. Instead of the bases being machined out of Stainless or another quality metal bar, they actually took metal sheet, rolled it and braised or welded the seams and ground them down. The ends are "open/filled with potting material and you can see that the stem of the lamp is not even centered within the sheet metal rolled base. We're talking tens of thousandths off center. I'm guessing it might be a production quartz envelope assembly that they shoehorned into some make-shift bases. Not to worry though because I completely understand these are prototypes and anything goes during development so I almost expect to see lots of flaws.

Disassembled the front end of the light that does not work. I'll snap some pics to illustrate. Technically, the light is focusable via installing shims between the white plastic spider assembly and where the front rim of the reflector contacts it. This is because the non-flanged rear hole of the reflector rides against a rather large spring and can slide further back on the round sleeve that houses the brass contact fingers. But I see no evidence of shims in either light, though.

But I'd still love to know how they attempted the 2-stage focus procedure. Stage 1 being the placement of the arc at the exact focal point of the reflector and Stage 2 being placing the pinpoint of light created by the Elliptical reflector at the precise correct point of contact with the Plano Convex lens. There's no way I can see to do this while the light is running.


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## get-lit (Nov 30, 2012)

*Re: 1,000 Watt Military Short Arc Behemoths*

Sounds like you need a different lamp make altogether. If you haven't already, perform an amp/volt test on the ballast, careful to hook up only after full ignition, and then look through the Osram XBO spec sheets to find a lamp to go with, considering power requirements and physical dimensions.


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## sven_m (Nov 30, 2012)

*Re: 1,000 Watt Military Short Arc Behemoths*



get-lit said:


> [...] that would only be an additional 37.5W of heat which is minimal compared to the 800-900W of heat it's made to deal with.



I wonder how much infrared they emit. Or what if the infrared of the hot electrode itself was focused back?


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## get-lit (Nov 30, 2012)

*Re: 1,000 Watt Military Short Arc Behemoths*

That lamp's total while light output is under 150W and infrared under 15W (10% of white light output for Xenon), and very little UV. So even with as much as 25% reflection, that would be 37.5W white light and 3.75W infrared totaling 41.25W, still just a 5% additional heat load which shouldn't phase the anode at all.


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## BVH (Nov 30, 2012)

*Re: 1,000 Watt Military Short Arc Behemoths*

I'll have the guys at A.R.C. build one or two for me. It runs at about 19.5V and 49 Amps as measured and posted earlier in this thread. About 950 Watts. The trick will be to establish the critical measurement from Anode base end to tip of Cathode and then I'll have to somehow ensure that the tapered hole in the new Anode base end is exactly the same diameter and depth as the original so the lamp actually sits exactly as it does now relative to Cathode tip/reflector focal point since there is no way to really change focus without shims and trial and error. But then again, who's to say the focus was right to begin with.


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## get-lit (Nov 30, 2012)

*Re: 1,000 Watt Military Short Arc Behemoths*

Sounds good, just be sure to check for an off the shelf solution first so that you have a reliable ongoing source.


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## sven_m (Nov 30, 2012)

*Re: 1,000 Watt Military Short Arc Behemoths*



get-lit said:


> That lamp's total while light output is under 150W and infrared under 15W (10% of white light output for Xenon) [...]


 Oh dear, managed to confuse power with intensity, thanks!
Could you imagine the radiation of the hot anode itself being thrown back?


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## get-lit (Nov 30, 2012)

*Re: 1,000 Watt Military Short Arc Behemoths*

Yes, I believe all subsequent radiations would be included in the entire spectral output measurement.


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## BVH (Nov 30, 2012)

*Re: 1,000 Watt Military Short Arc Behemoths*

Just another observation. The front of the reflector rim sits into a machined area in the lights casting. Another evidence of prototype quality is that I can move the front of the reflector up and down about a total of .015" and the same side to side. I would guess that this amount of movement would degrade the direction that the beam is being shone out thru the .300" hole towards the Plano Convex lens. Also, the hole at the back of the reflector is probably .010" to .015" larger than the sleeve it slide over, adding more chance of a slightly mis-directed beam. I might try to shim the front at some point.

Any optics experts out there that can describe what I would be looking for when trying to focus the lamp into the focal point of the reflector? I know with a Parabolic system, I look for the smallest hotspot on a flat surface some distance well in front of the light before the donut hole appears. With an Elliptical, I know it focuses the light into a pinpoint somewhere near just beyond the front of the reflector. In this case, the rear of the Plano Convex lens is around 8-10" from the front of the reflector. So as the lamp is moved in and out, does the position of the pinpoint change or does the pin point itself soften/get blunt?

EDIT: Just did a quick search and found this great interactive tutorial:

http://zeiss-campus.magnet.fsu.edu/tutorials/ellipticalreflectors/index.html


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## get-lit (Dec 1, 2012)

*Re: 1,000 Watt Military Short Arc Behemoths*

Notice in that tutorial what happens when you shift the bar to the right, the light hits the anode base, which would discolor the metal.


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## sven_m (Dec 1, 2012)

*Re: 1,000 Watt Military Short Arc Behemoths*



get-lit said:


> Yes, I believe all subsequent radiations would be included in the entire spectral output measurement.



Oh, sorry for the confusion: I rather meant the "the 800-900W of heat" of the electrode, not the primary radiation of the xenon.
What if some noticeable amount came back?

I guess it can't be plain overheating because the glass would have melted earlier. And that's why reflection came to my mind.

And although the spot looks quite distinct (indication of a forementioned local weakness?), metal perhaps might just melt like this?

But a local weakness of the electrode certainly might the best bet. My suggestion was just thinking about other possibilities.



BVH said:


> So as the lamp is moved in and out, does the position of the pinpoint change or does the pin point itself soften/get blunt?



The projection in the animation shows what happens at the true focus point. But you don't know this point and the light is too bright and hot to locate it with a cover or alike.
What the animation doesn't show well: slightly before or after the true pinpoint on the axis it will focus as well but with some errors (much like a caustic curve), which result in a noticeable loss in effect, though. Knowing the true position of the lens would help a lot, but if I got it right, you don't have it.

I'm thinking about searching the best focus with the lens, taking a picture of the spot in appropriate distance, say 100 ft. Then moving the bulb a bit, taking a note of the position, refocusing with the lens, taking another picture. And so on. Making a series of focus pictures, just to be able to compare them at one glance (instead of making two adjustments each time) and eventually fixing the bulb in the most appropriate position according to the pictures.

But that sounds backwards. I hope there's a more elegant solution.


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## BVH (Dec 1, 2012)

*Re: 1,000 Watt Military Short Arc Behemoths*

Just noticed the 2nd lamp also has the same melt spot. Not quite as big but it's there. This lamp is darkened somewhat within the chamber as if the Tungsten has vaporized and deposited itself on the Quartz.

sven, I see where the focus process you describe could work. I do have the lens. But instead of moving the lamp (which is not moveable) I would shim the reflector back (because it is already at it maximum forward position against the white plastic spider). So my only available direction to focus is in effect, moving the arc forward in the reflector. (Unless I choose to grind some of the white plastic spider). So I can make some shims in about .002 - .003" material and shoot photos against a distant target noting the smallest hotspot. Once I establish the smallest hotspot, then I begin moving the finned snout of the light (which contains the lens) forward (because it cannot go back). If it provides a smaller spot when moving forward, then I would end up shimming the snout casting out a little. It's just obvious that they did not provide any means of fine focusing when they built it.


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## BVH (Dec 1, 2012)

*Re: 1,000 Watt Military Short Arc Behemoths*

Here is a scaled drawing using measurements obtained with my metal scale and plotted in AutoCAD. I find it interesting that the distance from the front of the reflector to the baffle hole is (within the capabilities of my non-precision scale readings) within 1/8" of being identical to the distance between the baffle hole and the back of the lens. Get Lit, you've done a ton of reflector work - my "light waves" lines at the extremes of the reflector and lens show that all the collected light does, in fact, get pushed thru that tiny baffle hole. Is this reasonable given the 25 degree angle I show and what an elliptical reflector does? I obviously don't know where the focal point of the my reflector is but based on what I think is about a 115 degree angle of the light wave at the extreme of the reflector in the tutorial, I drew that in my drawing and it ends up reasonably near where the focal point looks to be in the tutorial.







How it's assembled into the light: (The metal scale represents the location of the baffle hole)


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## BVH (Dec 1, 2012)

*Re: 1,000 Watt Military Short Arc Behemoths*

I just compared the two lamps side-by-side. Their overall length is the same as is to be expected. But the critical dimensions - the end of the Anode bases to the tip of the Cathode electrodes - are a full 4mm different. Here's the interesting part. There is no easy means of field focusing the light as I have beat to death above. The lamps have no brand markings on them as I believe they are special made for this prototype development. But they do have a two-digit marking on them. One is marked "46" and the other, "49". The lamp marked 46 has a Base-to-Cathode dimension of 98mm. The lamp marked 49 has a Base-to-Cathode dimension of 95mm. So if I fill in some blanks:

Lamp 46 Base-to-Cathode = 98mm
Lamp 47 Base-to-Cathode = 97mm - A guess
Lamp 48 Base-to-Cathode = 96mm - A guess
Lamp 49 Base-to-Cathode = 95mm

I am guessing they used a series of lamps with progressively smaller Base-to-Cathode dimensions until they found the sweet spot/optimal focus. Or maybe they used different lamps to get a tight or flood focus depending on their needs.


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## BVH (Dec 2, 2012)

*Re: 1,000 Watt Military Short Arc Behemoths*

I seem to be the only one answering my own posts. I'm trying to chronicle everything I'm doing in case someone else comes up with one of these. FritzHID gave me this idea to add focusability to the light when I have a new lamp made and I plotted it to scale in AutoCAD to see if it would work. Looks like it will. Thread is .500" in diameter, fine thread. That's a machined thinner nut between the two base pieces if you couldn't tell. I'm going to have it made so that when the pieces are screwed together completely, the Anode base to Cathode tip will be 2mm less than it is now and then I'll have the ability to go 4 mm the other direction. That should cover all possibilities. I'll make and supply Advanced Radiation Corp. the bases out of 316 Stainless or whatever material they recommend. They'll make and assemble the rest.







By the way, I really enjoy using my lathe and mill to make parts like this and have lots of time on my hands. I wouldn't mind making similar parts for members who do modding. I'd be one heck of a lot cheaper than a machine shop. I also enjoy making the AutoCAD drawings and could do that for cheap, too. (End of shameless plug)


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## get-lit (Dec 6, 2012)

*Re: 1,000 Watt Military Short Arc Behemoths*



BVH said:


> By the way, I really enjoy using my lathe and mill to make parts like this and have lots of time on my hands. I wouldn't mind making similar parts for members who do modding. I'd be one heck of a lot cheaper than a machine shop. I also enjoy making the AutoCAD drawings and could do that for cheap, too. (End of shameless plug)



That's good to know, I'll keep that in mind.


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## 127.0.0.1 (Dec 6, 2012)

*Re: 1,000 Watt Military Short Arc Behemoths*

glad BVH is doing this and not me !

never have CPF threads conveyed as much danger through my computer screen as seeing one of BVH's 
voltage monsters broken down and studied. I still think I am the one about to be shocked, or glass bits in my eye
just looking at his pictures


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## BVH (Dec 6, 2012)

*Re: 1,000 Watt Military Short Arc Behemoths*

I'm fairly sure it shouldn't be me fooling around with high KV because I had Atrial Fibrillation for quite a while and was lucky enough to have suppressed it with my second Cardiac Ablation last April. Who knows what minor, let alone major "hits" might do to me. But I just can't help myself. I love HIDs and more specifically, Short Arcs. I am careful most of the time. I always suit-up" with welders' leathers, safety glasses and face shield when handling any lamp over 100 Watts. I just finally nabbed a great universal arc lamp power supply with large lamp housing to be able to test my 400 - 1200 Watt lamps safely inside a metal enclosure.

http://www.ebay.com/itm/Oriel-66022...Domain_0&hash=item460a9595a8&autorefresh=true


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## nealitc (Dec 7, 2012)

*Re: 1,000 Watt Military Short Arc Behemoths*



BVH said:


> By the way, I really enjoy using my lathe and mill to make parts like this and have lots of time on my hands. I wouldn't mind making similar parts for members who do modding. I'd be one heck of a lot cheaper than a machine shop. I also enjoy making the AutoCAD drawings and could do that for cheap, too. (End of shameless plug)



I'm expecting to need your services soon, if you don't mind working on 20KW lights...


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## BVH (Dec 7, 2012)

*Re: 1,000 Watt Military Short Arc Behemoths*

Would love working on those beasts! Handling a lamp might just give me some jelly knees!


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## Patriot (Dec 9, 2012)

*Re: 1,000 Watt Military Short Arc Behemoths*



BVH said:


> I always suit-up" with welders' leathers, safety glasses and face shield when handling any lamp over 100 Watts. I just finally nabbed a great universal arc lamp power supply with large lamp housing to be able to test my 400 - 1200 Watt lamps safely inside a metal enclosure.
> 
> http://www.ebay.com/itm/Oriel-66022...Domain_0&hash=item460a9595a8&autorefresh=true




Gosh, you're so responsible Bob! ...and to think, all I do is make sure my fly is zipped up! Okay, well all know that I don't even handle 100 Watt lamps. I'll stick to safer things... like machine guns! 

Awesome power supply! Woohoo buddy!

Glad to hear all went well with your surgery. I didn't know you had been dealing with that.


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## get-lit (Dec 11, 2012)

*Re: 1,000 Watt Military Short Arc Behemoths*



sven_m said:


> Oh, sorry for the confusion: I rather meant the "the 800-900W of heat" of the electrode, not the primary radiation of the xenon.
> What if some noticeable amount came back?



My sense tells me this is not the issue. Only heat within the IR spectrum can be reflected back. IR is 10% of visible output. Even subsequent IR from the anode would be included in that 10%, because when taking measurements, a spectral meter can not distinguish whether radiation is emitted from the plasma or the anode.

The anode can handle a very large margin of additional heat, much more than the just a moderate amount of light reflecting back to have an affect upon it. Not saying it's impossible, but it would take a large majority of the light, but even that "should" be well within the heat margin of the anode.

Also, if the anode were over-heated hot enough to melt it, the anode seal "should" rupture first.

Lamp makers design the physical structure of the anode specifically to prevent heat pockets within it, and by the looks of the shortcuts taken with the other lamp components, I wouldn't be at all surprised if the anode is just not up to the task.

This is such an odd thing, especially happening with two lamps, I honestly haven't a clue what's actually happened, just putting my thoughts out there.


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## get-lit (Dec 11, 2012)

*Re: 1,000 Watt Military Short Arc Behemoths*

BVH, I was catching up on some old reading and came across a post from you in 2007 about the AV/VSS-1 and wanted to make sure you're aware of something that would save you whole ton of lamp life when tinkering around.. You said "I have not run it longer than about 45 seconds because I’m concerned about the fan not running after the bulb is turned off." With each ignition, the lamp needs to be operated to full temp before shutdown, probably at least 90 seconds.

Useful info from the Ziess website.. "After a metal halide discharge lamp has been started, it should be allowed to warm completely to the recommended operating parameters (temperature and pressure) before it is turned off. In many cases the lamps are fully operational after a minute or two, but this value depends upon lamp design and specifications. After ignition, the lamp filler components (mercury, halides, and rare earth elements) vaporize in successive stages, while the lamp voltage, electrical output, and luminous flux gradually increase until they reach steady-state operating conditions. Rare earth elements are the last of the fill gases to evaporate so that metal halide lamps generate a blue-shifted spectral distribution until warm-up is completed. Shutdown is the reverse of startup with the rare earth elements being the first to condense. Premature termination of lamp operation can lead to rapid deterioration of the electrodes and blackening of the inner envelope walls, thus compromising future lamp performance. In effect, if a lamp is accidentally switched off too quickly during the startup phase, the filler components (mercury and rare earth halides) are often deposited on the internal walls of the envelope and on the electrodes. This artifact can be visualized as a dark opaque coating and can adversely affect re-ignition (in rare cases, permanently). In addition, the number of lamp startups has a significant impact on the life span, with more frequent ignitions leading to shorter lifetimes regardless of whether the lamp has been allowed to reach its proper operating temperature on each run before powering down."

I once shut down half way though startup and was left with the darkened glass, which I was lucky to have clear up after several cycles, each taking abnormally long to complete. I'll always be sure to allow at least 90 seconds for full startup.


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## BVH (Dec 11, 2012)

*Re: 1,000 Watt Military Short Arc Behemoths*

Thanks for that info Get! I have come to learn this over the years since that post. I even came across some factory-included instructions that come with each General Electric Marc300 Series lamp that instructs the user to run the light a minimum of 3 minutes between ignitions. I'm sure for the reasons you cite above. I would guess pure Xenon would require less time but for a different reason, Cermax wants their lamps run for a minimum of 2 hours the very first time of operation so that the point of arc origination is firmly established to ultimately eliminate or reduce flickering due to arc origination point jumping. They say to try to reduce short run times for the same reason because the high energy strike can repeatedly "cut" new origination points adding to the flickering problem.


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## BVH (Dec 23, 2012)

*Re: 1,000 Watt Military Short Arc Behemoths*

My new Dual "S" Abyss is for sale over at the Marketplace.


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## SPIKE1 (Jan 2, 2013)

*Re: 1,000 Watt Military Short Arc Behemoths*

BVH, 
very interesting read, and there is nothing wrong with a shameless plug, as you put it.
A thought that crosses my mind is that marconi as was in leicester is about 30 miles from me, now around 20 miles away is a place called bruntingthorpe, where they have just got a vulcan bomber back to flight, a lot of the workforce on that project were old workers from marconi, as these seem to be aerospace would it not be in your interests to contact them to do a bit of digging? i know a couple of guys involved and will ask some questions but dont hold your breath as there were around 5000 technicians on the project. also in leicester is a place called Brush electrical engineering these had close links as they built some military stuff but mainly developed loco's. also the main offices and factory of General electric were only a spit away, these were all in the same mix in the 90's with military stuff and experimental trains, so someone must know.
BTW nice video, they say a picture is worth a thousand words, and you certainly proved that one. Spike (very impressed).


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## BVH (Jan 3, 2013)

*Re: 1,000 Watt Military Short Arc Behemoths*

That sure sounds like a good possibility to find out some info. I won't hold my breath but one never knows! all it takes is one person to get it going. I'd be happy to carry the ball if you come through with a name and email to get me going. Thanks for you efforts!!


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## Ceya! (Jan 4, 2013)

*Re: 1,000 Watt Military Short Arc Behemoths*

BVH, 

I have been up for the past 4 hours reading up on Marconi and trying to piece together Le McAllister Control Engineers.

What I found on Marconi is very interesting like our British inventor of 4,000,000,000 light.

I still have a lot to search for but it is an idea that they may been fitted for the type of planes listed below.

British NIMROD planes below.

http://en.wikipedia.org/wiki/Hawker_Siddeley_Nimrod#cite_ref-neal_120_33-2
The Nimrod could also be fitted with two detachable pylons mounted underneath the wings to be used with missiles such as the Martel;[33]​ two specialized pylons were later added to enable the equipping of Sidewinder missiles, used for self-defense purposes from hostile aircraft.[35]​*A powerful remote-controlled searchlight was installed underneath the starboard wing for SAR operations.[33]​ For reconnaissance missions, a pair of downward-facing cameras suited to low and high-altitude photography were also equipped on the Nimrod; [33]​ in later years a newer electro-optical camera system was installed for greater imaging quality*.[44]


​I found the ad for your lights in a British Army site, ARRSE. When they seller was trying to sell them back in July 2012.
http://www.arrse.co.uk/classified-ads/185607-2-x-ex-mod-experimental-prototype-searchlights-45kv-very-powerful-very-rare.html

After reading your first post , I think these may be the ones or similar.

I'll continue later.

S/F, 
CEYA!


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## BVH (Jan 4, 2013)

*Re: 1,000 Watt Military Short Arc Behemoths*

Ceya, yes, those are the actual lights I acquired. He had no luck there so moved them to Ebay. Thanks everyone who is contributing to trying to find any history on these. I'm having a hard time seeing these used on aircraft. They use a 1 degree, non-changeable beam which doesn't make a lot of sense for installation on a fast-moving, fixed-wind aircraft.


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## Ceya! (Jan 4, 2013)

Remember when using for SAR, you are not moving fast at all.

Needing the light to acquire the target. Even with the Recon planes then you are trying to get much information from the pictures.

They were moving fast to get to the target but at a control speed once they were taking pictures.


What is non changeable on the light? 

No problem on the research, it is the fun part.

S/F, 
CEYA!


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## BVH (Jan 4, 2013)

There is no focusability of these lights. The beam is fixed at a very narrow 1-2 degree beam, so not so great for SAR. These do not strike me as helicopter lights. 
Too heavy and massive. If they were on fixed wing aircraft, an operator would have a very tough time trying to find anything and then keep it in the very small spot.


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## TEEJ (Jan 4, 2013)

For a fixed wing application, where typically, the guns are also fixed...a fixed target light would actually work.

IE: When the light was on the target, the guns are aimed at it.


Similarly, a long range landing light would also be aimed where the plane was going....analogous the pencil beams on a car, etc.




Plan C - The theory that it might have to do with radar or target acquisition jamming somehow...in that the plane, etc, would merely be a test mule, and the lights were to shoot at a test bed/installation for proof of concept.

If you find the emitter has some extra circuitry or other means of modulating the output/frequency or other atypical parameters...that might be a clue.

For example, there are laser range finders for targeting...and if this light were aimed AT the targeting laser's receiver, it might jam it?


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## Ceya! (Jan 4, 2013)

You don't need a light to be flooded in military just line of sight to target, for ground tactical rescue to see.

The less flood the better not seen by many.

I can see as a jamming idea since Marconi made his mark in wirless, radar like Telsa and our british friend ( name is not here again).

Maybe light on target during recon picture being taken? 

1 to 2 degree of angle movement is small but on the ground its bigger.

S/F,
CEYA!


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## jh333233 (Jan 5, 2013)

Sounds like a retrofuture alien death ray in Fallout series
Awesome!


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## BVH (Feb 11, 2014)

A great deal here:

http://www.candlepowerforums.com/vb...e-enthusiast&p=4378466&viewfull=1#post4378466


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## johng.davies (Apr 6, 2014)

*Re: 1,000 Watt Military Short Arc Behemoths*



BVH said:


> Thanks snake. Might you know of anyone who may have worked at the Leicester plant who might know something about these?
> 
> Driver your right about the noise being loud for a light. But it sure sounds great and adds to the mystic of the lights. These certainly won't be "casual use" lights with all the equipment needed to run them away from a 240 Volt outlet. I could do it now but it would take my 175 lb, 4.5KW generator, the 85 lb Lorain and its' #4 cables, 30 lbs of hook-up cables, 55 lb power supply and 70 lb light. I'd love to spring for some high Amp Hour, custom 7-cell SLA's but they are way too much money for very occasional use.



hi
I used to work fo gec-aei at the leicester blackbird road factory from 1966 and then at the new parks factory from 1968 till 2001.
I lived very close to the blackbird road site and searclights were regularly being tested in the dark evenings, these searchlights were for military vehicles i believe


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## BVH (Apr 6, 2014)

*Re: 1,000 Watt Military Short Arc Behemoths*

Thanks johng! Every bit of info is helpful in my quest to get these running again.


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