# VFD Conversion again



## alexmin (Feb 12, 2010)

My PM1236 has 2hp 1 phase motor.
I was contemplating getting a new 10hp VFD (derated 5hp) and new 
5hp 3 phase motor so I can run my lathe without changing gears.

Unfortunately this setup costs around $600 or more. 
Due to certain budget constrains imposed by my lovely spouse all I can afford in near future is a 2HP 3phase motor that I can use with the VFD I already have(it can drive a motor up to 2hp) 

A new motor will give me a soft start, smoother motor and really low min RPM. I still have to keep changing gears though. 

What are your thoughts about it?


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## 65535 (Feb 12, 2010)

Save up your budget constrained allowances for the 5HP motor?

No point in going with the same HP motor IMO you'll just regret not having the cash to buy the 5HP setup.

A 5HP motor will produce more power than the 2HP stock motor until you dip below 40% RPM, at that point you'll want to change gears no matter what unless you're working on a small part.

Anyways that's what I would do.


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## liveforphysics (Feb 12, 2010)

My VFD's let me over-drive the motors up to about 300% of rated capacity. 

I run 1hp TEFC 3P motors at 3hp for about 20 minutes continously, and I've never had any trouble. The motor gets warmer than usual, but motor heat isn't a big deal for brushless induction motors. 

I would imagine you could run that 2hp motor as a 5hp motor just fine as long as you're not planning on doing very extended time runs.


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## alexmin (Feb 12, 2010)

liveforphysics said:


> My VFD's let me over-drive the motors up to about 300% of rated capacity.



What is this "over-drive" option? Do you just set your VFD like if it is driving 3hp motor but connect it to 1 hp motor?
My VFD (KBAC-27D) has jumpers to select different horse power modes but the max is 2 hp.


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## 65535 (Feb 12, 2010)

Running a motor above 100% RPM (or above 60Hz) will start to lose torque very quickly. At 300% rpm, if the motor hand not grenaded, it would produce poor torque and no where near 300% HP.

I'd like to know what brand VFD and motor are capable of that, and what machinery they are on.


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## brickbat (Feb 12, 2010)

65535 said:


> Running a motor above 100% RPM (or above 60Hz) will start to lose torque very quickly. At 300% rpm, if the motor hand not grenaded, it would produce poor torque and no where near 300% HP.



Right. When a VFD is used to operate a motor above its rated speed, torque drops off. Generally, the motor enters a constant horsepower region above 60 Hz, where, for example a doubling of speed will mean a halving of torque.

That said, fitting your lathe with a 2HP VFD and motor will still be a significant improvement, IMO. It will reduce the number of gear shifts. BTW, check prices on a 3HP drive - the big step in pricing seems to be at 5HP, and the 3HP drives aren't much more expensive than the 2HP models.

I put a VFD on my 1 HP Tree milling machine to reduce the number of times I need to change the belt drive ratio (It has multiple sheaves), and it's been great. Sure, some times, I need lots of torque at the spindle, and have to change the belt ratio, but lots of times, I don't and just leave the belt ratio at a mid-value and adjust the VFD. 

My lathe is variable speed, and it's really nice to see the way you can dial in a sweet spot for the best surface finish during a cut - kinda hard to do that if you have to change gears!

And, while you might NOT want to attempt to run your motor at 300% of its nameplate speed, you can certainly hit 150% with no issues...


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## wquiles (Feb 12, 2010)

alexmin said:


> What are your thoughts about it?


I would wait until you can afford what you "really" want. Second choice, get at least a 3HP 1750 rpm quality motor - that will be a significant improvement over the stock motor.

Will


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## liveforphysics (Feb 12, 2010)

I do not triple the RPM of the motor. I go from 60hz to maybe 90-100hz max, but I don't require any over speed to double-triple the motor power. 

I use a Yaskawa VFD that takes in 220 single phase, and outputs 440v 3p with user selectable current weakening and current phase limits. The drive was ~$320 used on Ebay if I remember correctly. 

I pair the motor windings to be configured for 220v 3P (to lower winding resistance to enable higher current draw ability), then wire it to the 440v 3P VFD output, and simply use phase current controls to limit the amount of power the motor is getting. I can make it some the motor is drawing less than 100w, all the way up to 4kw on the same motor by setting the phase current limits. The phase currents determine the torque of the motor, the frequency determines the RPM, and the RPM*torque determines the power. 

Best Wishes,
-Luke


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## brickbat (Feb 12, 2010)

liveforphysics said:


> The phase currents determine the torque of the motor, the frequency determines the RPM, and the RPM*torque determines the power.



Exactly. 

So, help us understand what's happening when you get triple the motor's rated power. If you're getting that at the motor's rated speed, as you say, then wouldn't the motor be delivering triple the torque? And in doing so, draw triple the current? And it does that for 20 minutes without emitting smoke? WOW!! That's one amazing motor, or you have one helluva cooling system for it...


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## liveforphysics (Feb 13, 2010)

Exactly, triple the current, roughly triple the torque (not a perfect triple due to saturation losses, increased eddy currents, etc.), and triple the power for a given RPM. 

Tripleing the current has the same effect on torque as adding a 3:1 gear stage, but with out the 1/3 drop in RPM, but at the expense of drawing 3 times the power (and outputting 3 times the power). 

Of course that's all +-10-15%. Efficiency curves are funny with induction motors.  


The motor can handle things thermaly because the rate it can transfer heat into the air around it depends on the difference in temp between the air exposed surfaces, and the rate air moves past it. When they rate a quality motor (I use baldors), they rate it for essentially a worst case scenerio situation. I give the motors a situation with active cool airflow, in return, they increase to a higher temperature with higher power levels, and find the new thermal equilibrium temp (still in a safe zone) and hold just fine.


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## brickbat (Feb 13, 2010)

A motor drawing three times its nameplated current is dissipating roughly 9 times its rated power in resistive losses. (Most of the power lost to heat in an induction motor is lost in the resistance of the stator and rotor conductors) And of course, tripling the current through a resistor causes 9 times the power to be lost in it.

Now, as I understand heat transfer, in order for the motor to dissipate that much heat, that motor would need to be at (again roughly) 9 times the temperature RISE for which it was rated. In other words, if the motor rating was at, say 40C rise over ambient at its nameplate current, and given that you'r not really changing the cooling system (Its TEFC, right), wouldn't the motor now rise to roughly 360C above ambient? In steady state, anyway.

Any chance your VFD is computing input power incorrectly, since its wired for 480V? Or have you actually confirmed you really are putting a line current of 3 times the nameplate into the motor? - triple 3.5 amps is about 10.5 amps, right? A decent motor could do that for short periods of time, but after 20 minutes, it'd be a TESG motor (totally enclosed smoke generator)

I'm sure you've heard of the magic smoke theory of electrical devices....  Just because it's a "totally enclosed" motor, doesn't mean the magic smoke won't leak out . Trust me on this - I have some recent experience with a 6" belt sander in this area. There's a lot of nasty smelling smoke contained in a TEFC motor...


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## precisionworks (Feb 13, 2010)

> My VFD's let me over-drive the motors up to about 300% of rated capacity.
> 
> I run 1hp TEFC 3P motors at 3hp for about 20 minutes ...



I'm not an electrical engineer, nor a VFD expert, but I've set up a few dozen drives. Never have seen one that allows what you describe *unless* you have a 3hp drive controlling a 1hp motor. Configure the drive parameters so that the drive is set up for the full load amps of the 3hp motor & the drive will happily pump out all the current demanded by a 3hp motor. It will work until the motor gets tired of that abuse & smokes out, but 3ph motors are cheap enough that you can keep a few on hand 

Speaking of which, it makes a lot more sense to buy a 3hp motor. With 3X the torque and 3X the hp, the larger motor will do more work more easily than a little 1hp motor that's operated well beyond design limits.

FWIW, a number of current CNC lathes, mills & machining centers are dual hp rated. Something like 10hp continuous and 15hp for 15 minutes. Again, this is done by sizing the drive for the largest hp (15hp in this example), running a constant speed cooling fan, limiting the over drive to 150%, and limiting the time to 15 minutes of full load use. 

300%, no matter how you get there, is a recipe for failure. Even the most heavily constructed Vector Drive motor or TENV motor will have a short life under those conditions.


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## precisionworks (Feb 13, 2010)

> A new motor will give me a soft start, smoother motor and really low min RPM. I still have to keep changing gears though.


The VFD will do all of the above, plus provide instant reverse for power tapping, plus instant stop, plus allow for an increased top speed (run the max freq to 90 Hz and your top speed will be 150% of current max, as long as the spindle bearings will tolerate that).

No reason not to do that since you already have the drive & a 3ph 2hp motor is pretty cheap on eBay


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## alexmin (Feb 13, 2010)

precisionworks said:


> The VFD will do all of the above, plus provide instant reverse for power tapping, plus instant stop, plus allow for an increased top speed (run the max freq to 90 Hz and your top speed will be 150% of current max, as long as the spindle bearings will tolerate that).
> 
> No reason not to do that since you already have the drive & a 3ph 2hp motor is pretty cheap on eBay



Barry,

you made my day! 

I am ordering a new 3ph 2hp motor. 
Eh, what the hell, when I get a 5hp setup I can always use extra 2hp motor to make a VFD conversion for my drill drill press or band saw!


BTW Where can I get a pulley for PM1236? It seems to have unusual double belt configuration.


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## precisionworks (Feb 13, 2010)

> Where can I get a pulley for PM1236?


As someone will surely say ... you have a lathe, make one  But I wouldn't (been there, done that, costs way too much in time).

You may want to look at stacking a pair of single groove cast iron sheaves, like those in the Browning BK series:

http://www.emotorstore.com/productD..._A_subCatID_E_325_A_catID_E_17_A_brandID_E_23





Or look at a Baldor/Maska sheave like the MAS42 or MAS53.

http://www.maskapulleys.com/images/produit/sheaves.pdf

Look on page 20 for specifics.


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## liveforphysics (Feb 14, 2010)

precisionworks said:


> Never have seen one that allows what you describe *unless* you have a 3hp drive controlling a 1hp motor.


 
Just a 3hp drive on a 1hp motor alone wont do it, unless you're loading it to have a crazy slip percentage, but then inductive heating would be awful.

The trick is to run a 3hp drive at 440v on a 1hp motor terminated for 220v. The winding resistance is halved, allowing the drive to easily control phase currents to be 2-3x higher (just like if it had a real 2-3hp 440v motor for a load). 




precisionworks said:


> Now, as I understand heat transfer, in order for the motor to dissipate that much heat, that motor would need to be at (again roughly) 9 times the temperature RISE for which it was rated. In other words, if the motor rating was at, say 40C rise over ambient at its nameplate current, and given that you'r not really changing the cooling system (Its TEFC, right), wouldn't the motor now rise to roughly 360C above ambient? In steady state, anyway.



If the motor winding was only a resistor, this would be the case. Fortunately it's an inductor/resistor.  

Motor heat is best modeled at Pin-Pout = Heat. Otherwise in the example above, you've got some over-unity power creation happening in the motor, and I wana get in on that gig! 


The difference between Pin to Pout is determined by the efficiency of the motor. It also is roughly a constant value up until you get saturation. This is why it's important to use a quality motor with thin lams. 

Likewise, efficiency of the motor is of course critical. 
A motor making 3hp at 70% efficiency is making over double the heat of a motor making 3hp at 85% efficiency. 

A relatively small improvement in motor efficiency has huge impact on heat. 


Lastly, looking at the heat transfer abilities, what is different in the cooling abilities of motors in the same NEMA package size (at least for TEFC)? Same rotor, same lams, same little fan, same RPM, same case material, same surface area. The difference between the 1hp and the 3hp for motors that have the same package is just the winding resistance. You can copy that lower resistance by terminating the motor voltage tap windings in parallel rather than series, or if you wish to go one step further (or an in-between step) you can terminate in delta rather than wye, and use the the drive frequency to compensate for the RPM change. 




precisionworks said:


> 300%, no matter how you get there, is a recipe for failure. Even the most heavily constructed Vector Drive motor or TENV motor will have a short life under those conditions.


 
I agree a motor sure can cook inside, and it's so cheap it's not a big deal to replace. 

However, with the VFD's automatic field weakening when it's not loaded, and my heavy load cutting duty cycle on the lathe being low, generally always sub 30%, the average thermal loading on the motor isn't too bad. I'm on the same motor, and it's been a champ for me for a few years now. It may be cooked and just about to let go inside, or maybe my low duty cycle never gets it over-heated, but as long as it keeps chugging along for me, I will keep being happy with it.  




I always chuckle at how big induction motors are relative to the power they produce. 

I build PMBLDC3P (permanent magnet brushless dc 3-phase) motors for light electric vehicles and large scale RC toys. I've got 9hp motors that are the size of a softball and 4lbs each, and affordable off the shelf items! Too bad the RPM range makes them require complex reduction stages for most applications.

Here is a pic of a pair of these monsters on my 65mph DIY E-bike.  The same power with induction motors would be 5 times the weight of the bike and batteries. lol 






http://www.hobbycity.com/hobbyking/...80-100-B_130Kv_Brushless_Outrunner_(eq:_70-55)




The record right now for a PMBLDC motor is 1.4lbs for 7hp continous. I'm shooting to break the record, so far I'm not even half way there though. lol. Dream big. 
http://www.launchpnt.com/about-us/n...owerful-new-halbach-array-electric-motor.html


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## brickbat (Feb 14, 2010)

liveforphysics said:


> … and my heavy load cutting duty cycle on the lathe being low, generally always sub 30%, the average thermal loading on the motor isn't too bad.



OK, wait. Earlier you said you got 3HP for 20 minutes continuous, and you got that at 100% of rated speed, right?





liveforphysics said:


> The trick is to run a 3hp drive at 440v on a 1hp motor terminated for 220v. The winding resistance is halved, allowing the drive to easily control phase currents to be 2-3x higher (just like if it had a real 2-3hp 440v motor for a load).



I understand, but don't see how it's a trick. I can see how, with a V/Hz drive, it would allow you to get, say 2HP at twice the rated speed out of a 1 HP motor, but it has nothing to do with your claimed ability to get 300% torque out of a motor. It’s a 480/240V machine, right? And rated line current is what, 3.5A @ 240V? And you get 300% torque, right?

At what line current? Wouldn’t it be in the neighborhood of 10.5 A?

OK, let’s agree on a simple motor model. (If you please, I know a motor is not a resistor, and I’m not making any extraordinary “Free Energy” claims.) 

Your machine is rated at 1HP, that’s represents about 750 W of mechanical output power. And let’s just say that your motor is 80% efficient at full load, which is typical for common 1 HP 3-phase induction motors. Therefore the input power is about 940 W. So, the motor is dissipating about 190W of heat, right?

I propose we model this loss electrically as a resistor, as is commonly done in the texts I’ve seen on AC machines. Physically, it arises from many sources, but the copper wire resistance of the stator, and the resistance of the conductors in the rotor dominate. If we were to increase the current through the wire and rotor conductors (as we’d have to do to get more torque) the current through these conductors also has to increase proportionally. Sure, we get more torque and thus more mechanical power out of the motor, but, if we double the current, the loss increases by the square, (P=I^2 R in a resistive component) so 4 times the resistive loss. Our original 190W of loss becomes 760W. And if we triple the current, the resistive loss again increases by the square, so 9 times 190W = 1710W of loss.

Without a mod to the cooling system, being able to dissipate 9 times the power means roughly 9 times the rise over ambient (assuming here that radiative loss is not significant for a motor's cooling).

Now, if you say you're running a short duty cycle, we can drop all this. Because at some small duty cycle, you can get 300% torque out of a motor without smoke, but not for 20 min at a time...


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## precisionworks (Feb 14, 2010)

Why does this remind me of the cheapo air compressors that claim 10hp from a 3hp motor


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## liveforphysics (Feb 14, 2010)

brickbat said:


> I propose we model this loss electrically as a resistor, as is commonly done in the texts I’ve seen on AC machines. Physically, it arises from many sources, but the copper wire resistance of the stator, and the resistance of the conductors in the rotor dominate. If we were to increase the current through the wire and rotor conductors (as we’d have to do to get more torque) the current through these conductors also has to increase proportionally. Sure, we get more torque and thus more mechanical power out of the motor, but, if we double the current, the loss increases by the square, (P=I^2 R in a resistive component) so 4 times the resistive loss. Our original 190W of loss becomes 760W. And if we triple the current, the resistive loss again increases by the square, so 9 times 190W = 1710W of loss.
> 
> Without a mod to the cooling system, being able to dissipate 9 times the power means roughly 9 times the rise over ambient (assuming here that radiative loss is not significant for a motor's cooling).




This is simply not the way a motor works my friend. 

The efficiency of the motor includes the resistive loss, and the efficiency is roughly fixed assuming the saturation points aren't reached. 

Lets use the 80% efficiency example.
At 1hp, it's 932w in and 746w (1hp) out, and 186w of motor heating.

At 3hp, it's 2796w in, and 2238w (3hp) out, and 558w of motor heating.

Lets say the motor efficiency tapers off to 75% when it's over driven. This would mean:
2984w in, 2238(3hp) out, and 746w of motor heating. 

What does it take to handle and increase of 4x the heating on a motor? 
Lots of easy options. 4x the airflow over the motor surface, 2x the airflow and 2x the delta-T, a motor mount that sinks to the large metal frame of the machine (as my lathe motor does), or lots of other options. 


Now think about this. When they make the 3hp version of the motor in the same NEMA frame/package, if the efficiency is similar, and the winding resistance is setup to enable it to draw the current needed to make the power, is there any difference?  


I play with the motor speed all the time for an easy adjustment, I think it's likely the biggest advantage of a VFD. If I need to chug through some harsh rough cuts or whatever, the current of course naturally ramps up as the slip% increases, and keeps ramping till it hits the VFD's programmed phase current limits (giving roughly 3hp). I just do hobby work rather than production work, so my loading is different than factory machine running constantly of course. I make a cut, measure, changing tooling, check run-out, make another cut, measure, work the math to figure out how much to trim off next, etc. Lots of time where the motor is just sitting spinning the lathe unloaded, and with the field weakening, it pulls a little under an amp at 220v (measuring power into the VFD) just free running. It's definitely getting cooling time and a friendly duty cycle. Most lathe jobs I do are finished in maybe ~20mins if I had to take a wild guess, it's not like I time myself when I'm just tinkering in the garage. In a situation with my Lathe where I needed extended high torque, I would gear down and freq up the motor to 90hz or so, which would of course let the phase currents decrease and still maintain the same torque at the lathe. 


Lots and lots of ways to skin a cat.  Lots of motor options, drive options, and setup of motors and drives. 

If you guys run your machines making cuts that put maximum motor loading on them long periods continuously, then by all means, get the toughest setup you can find, maybe over-size the motor. 

I may have badly perceived the posters intent for the machines use, but it seemed to me like he was more of a hobbiest like myself looking to add some function and ease of use to a machine, and do it on a tight budget. 

I offered a suggestion that has been working great for me. Didn't mean to stir up any trouble.


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## brickbat (Feb 14, 2010)

liveforphysics said:


> Lets say the motor efficiency tapers off to 75% when it's over driven.



That's a fascinating theory of yours - that an induction motor efficiency drops to only 75% at THREE times its rated torque output. Got a link to Baldor's specs showing that ? 

Efficiency curves for induction motors shown in my texts don't go to 300% of rated torque, but at 150% of rated torque, efficiency is dropping off FAST. The fact is that losses in an induction motor are predominately (Not totally, granted) resistive at high loads, and resistive losses increase as the square of the current. No way around Ohm's law that I've yet found...

No offense intended, but I'm concluding that your 20 minute/300% claim was, erm, optimistic. 

Maybe all we can agree on is that a 2HP VFD will be a nice setup for the OP's machine...

I suppose you have a physics background. Do you, by chance, have a text on AC machines handy? Mine are all pretty old, and I'd like to get something newer...

On edit:



liveforphysics said:


> This is simply not the way a motor works my friend.



The folks at Mathworks seem to think it is. Note particularly R1 and R2 in the model - they are resistors used to model the stator and rotor losses.

http://www.mathworks.com/access/helpdesk/help/toolbox/physmod/elec/ref/inductionmotor.html


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## alexmin (Feb 20, 2010)

I have received my 3PH 2hp Leeson motor. 
The PM1236 manual although shows both 1ph and 3ph schematic is absolutely useless for someone who does not have any electric engineering background. :mecry:

I am going to post some pictures of PM1236 electric box guts and hope to get some advise on hooking up my new motor.


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## StrikerDown (Feb 20, 2010)

precisionworks said:


> Why does this remind me of the cheapo air compressors that claim 10hp from a 3hp motor



Barry, How do they get those 5HP motors to run on 110V, 15A?


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## alexmin (Feb 21, 2010)

This is a picture of inside of the PM1236 electric box as it connected to 1 ph motor.
L and N (plus ground yellow/green wire) are 220V input wires. 
U1, U2, Z1 wires that go into 1 phase motor.
In the past I have connected 3 phase motor directly to VFD plus foot on/off switch.
This setup should be somewhat similar except there is an electric box and I have no idea how to put it all together.
I need all the on/off switches in the lathe to connect to my VFD "control interface" instead of just cutting and restoring power to the VFD.
Any help is very appreciated.


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## liveforphysics (Feb 21, 2010)

Though it looks daunting, it will only end up being maybe 3-5 control wires that need to be routed to the VFD, and then of course the motors phase wires need to connect to the phase out of the VFD. You won't need the contactor for On/Off anymore. That function will be happening in the VFD now. 

Unfortunately, with no wiring diagram, it's tough to trace that all out from a photo... 

If you can post up your VFD's connection diagram, and your Lathe's electrical diagram, we can do the color-code dots to show which wires to put where.


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## unterhausen (Feb 21, 2010)

I'm having trouble understanding why that rat's nest of wires and contactors is required for a lathe. How many motors does it have? I guess it's related to reversing. Can we download the manual? I looked at Grizzly, they don't have a downloadable manual for their lathe with what looks like the same wiring panel.


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## 65535 (Feb 21, 2010)

Forward reverse, change gears, maybe a light.

Not sure why so many wires, KISS did not apply here.


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## gadget_lover (Feb 21, 2010)

Most likely we have everything wired back to the control box. It also has the components permanently wired to the terminal strip at the bottom so you do not have to hassle with the connections at the contactors. That gives you twice (or 3 times) the number of wires you might have otherwise. 

The upper left component has a Vin and Vout, with input volt at 220 and Vout at 24volts, so it's for lights and possibly the coolant pump.

You'll probably do all your connections to the strip at the bottom. 

Somewhere there's an E-stop button. The cjx2-2501 modules are contactors, in essence remote controlled relays for the power. The jzc4-40 appears to be a relay, possibly connected to the E-stop. 

As the other poster said, the wireing diagram is needed to decide were the VFD will enter into the wiring.

Daniel


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## alexmin (Feb 21, 2010)

Wiring diagrams from the lathe manual:










---




--


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## 65535 (Feb 21, 2010)

Holy over complication. Good lord.


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## precisionworks (Feb 21, 2010)

The control photos are typical of many three phase lathe, mill, or general machinery control boxes.



> I need all the on/off switches in the lathe to connect to my VFD "control interface" instead of just cutting and restoring power to the VFD.



Step 1 - Remove the control box, including contactors, overloads, terminal strips, etc. They should bring something on eBay as long as you can describe what they are, the voltage, amp rating, etc.

Step 2 - Run 240v 1ph power to the VFD. Run 3ph output directly to the motor. Wire the Fwd-Off-Rev switch to the small logic terminals in the VFD.

Almost as simple as plug-n-play, although you may have to phone tech support to get the VFD configured for external command control (versus the green & red buttons on the keypad).


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## darkzero (Feb 22, 2010)

unterhausen said:


> I'm having trouble understanding why that rat's nest of wires and contactors is required for a lathe. How many motors does it have? I guess it's related to reversing. Can we download the manual? I looked at Grizzly, they don't have a downloadable manual for their lathe with what looks like the same wiring panel.


 
Although the G4003 is closer to the PM1236, only the G4003G manual shows the control panel, page 44 shows the control panel (much better manuals).

http://cdn0.grizzly.com/manuals/g4003g_m.pdf

Not sure how much of the control panel is different. I think the only main differences is the coolant pump/switch, foot brake's cut off switch, & the chuck guard cut off switch. Don't know if the G4003 has the switch for the drive train cover.


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## 65535 (Feb 22, 2010)

I was going to recommend ripping everything out and doing a simplified rewiring, but I didn't want to be the first to say it hehe. How's that for liability assurance.


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## Atlascycle (Feb 22, 2010)

You need to locate the main motor fwd and rev contactors and disconnect the 240VAC wiring from the top and bottom of the contactor. then connect the start stop wiring from the VFD to the contactors and your lathe controls will work as before, If I get time to mark up the photos I will repost them.

Jason


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## unterhausen (Feb 23, 2010)

65535 said:


> I was going to recommend ripping everything out and doing a simplified rewiring, but I didn't want to be the first to say it hehe. How's that for liability assurance.



I was going to say the same thing, but now that I've seen the wiring diagram, much of it is for switching. I guess it depends on how much of that the OP wants to keep.


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## 65535 (Feb 23, 2010)

All that should need to be done is to rip all the high current wiring out, rewire all the required switches E-stop, FWD/REV, maybe an ON/OFF in there and wire each on to an available terminal on the VFD to be programmed as a code in the VFD to do whatever needs to be done, Run, Jog, Stop, Reverse, what have you.


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## precisionworks (Feb 23, 2010)

The VFD replaces all the typical starters, overloads & contactors ... everything now contained inside your cabinet is useless when the drive is installed. If you feel a need to keep all the existing wiring, ditch the VFD idea & buy or build a rotary converter.


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## StrikerDown (Feb 24, 2010)

precisionworks said:


> The VFD replaces all the typical starters, overloads & contactors ... everything now contained inside your cabinet is useless when the drive is installed. If you feel a need to keep all the existing wiring, ditch the VFD idea & buy or build a rotary converter.



Based on this statement, it is a wonder that OEM's don't just build them all with a VFD. With economy of scale it seems it would not add to the cost a whole bunch. Of course a penny is still a penny in the grand scheme of bottom lines!


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## precisionworks (Feb 24, 2010)

> it seems it would not add to the cost a whole bunch


It would probably add $100 to a machine with a 1hp motor, and $150-$250 if the machine had a 2hp or 3hp motor. On machines assembled in Asia, where a highly skilled worker makes $4 per day, this would easily make some machines far too expensive. Lots of people don't mind switching a belt or a gear change lever, even though it's PITA ... and they will not consider spending a few hundred dollars for one of the best upgrades available.


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## StrikerDown (Feb 24, 2010)

precisionworks said:


> It would probably add $100 to a machine with a 1hp motor, and $150-$250 if the machine had a 2hp or 3hp motor. On machines assembled in Asia, where a highly skilled worker makes $4 per day, this would easily make some machines far too expensive. Lots of people don't mind switching a belt or a gear change lever, even though it's PITA ... and they will not consider spending a few hundred dollars for one of the best upgrades available.





StrikerDown said:


> Of course a penny is still a penny in the grand scheme of bottom lines!



Pennies on a machine like mine, I would galdly paid an extra $100 - $250 for that option installed. On the manufacturing end it probably wouldn't add even $20 - $30 to the overall cost by the time you take out the cost of all the hardware it replaces and figure the Mfg'er is buying in large quantity from another cheap Chinese electric supplier. Just a thought.


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## precisionworks (Feb 25, 2010)

There's a very small market for any non-CNC machine tool. Most every one is built to a price point, not to a specific quality level. The philosophy seems to be cheap is good & cheaper is better 

Tool posts are a good example of this. There are Asian versions for $100 and there is the Dorian SQCTP for $500. Dorian could lower that price if the quantities were higher, but that will not happen as 95% of new lathes and machining centers are CNC controlled ... and most CNC machines use a vector drive spindle.



> I would galdly paid an extra $100 - $250 for that option installed.



$22,995 and the vector drive spindle is free 
http://haasportal.net/Portals/57ad7180-c5e7-49f5-b282-c6475cdb7ee7/DS_TLseries_US.pdf


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## 65535 (Feb 25, 2010)

Tool pron alert.


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