# My VFD is having a stroke? (PM1440GT)



## LVLAaron (Jul 4, 2022)

Been using the lathe a ton, did a hitachi VFD conversion.
Out in the shop today working along on a project, get to the last op, and it sounded like it had broken something in the gearbox. I stopped and pulled the lid off the main gearbox, everything looks fine, turning all the gears by hand it's all smooth. No missing teeth or parts floating around.


The motor is herky-jerking and not running smooth, which is what's giving me the "broken gears" sound, it's chattering back and forth. I've attached a slo-mo but it's hard to tell in the video what's going on. The machine is in low with the speed pot set to where the motor would be running at 60hz 






The only thing I can think of doing is an "auto-tuning" in the VFD software.



Any help is greatly appreciated! I took the week off and have a lot of things to make!


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## DavidR8 (Jul 4, 2022)

Have any of the settings changed?
Have you powered the VFD off/on?


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## LVLAaron (Jul 4, 2022)

No changes. 

Yes, I have power cycled it.


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## DavidR8 (Jul 4, 2022)

What happens if you change the frequency on the VFD?


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## LVLAaron (Jul 4, 2022)

Same same. Doesn't matter where the pot is.


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## DavidR8 (Jul 4, 2022)

Very odd. Doing the auto-tune can't hurt I suppose.


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## LVLAaron (Jul 4, 2022)

No change with a fresh auto-tune. :/ 

At a loss.


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## DavidR8 (Jul 4, 2022)

Is there a possibility that there's a loose connection? A lot of use may have vibrated something loose...
Maybe a loose pulley?


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## mksj (Jul 4, 2022)

Take the belts off and check the motor with the VFD through the speed range and also try to apply some pressure on the pulley with a piece of wood and see if you feel any roughness. Try to turn the the headstock input pulley by hand and see if you feel any grinding or roughness.


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## LVLAaron (Jul 4, 2022)

Headstock





Motor with some wood.







Everything in the headstock feels like the day I got it. It's really hard to tell in video but the motor does some reversing jitters at the start and stop. I don't know if that's normal or not. 


Also, when I auto-tune, the VFD gives a fail - The display shows "_ _ _ _|" - i press stop/esc on the VFD and the software comes up with parameters... I dont remember if that's normal or not.


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## DavidR8 (Jul 4, 2022)

Everything looks pretty smooth in the second vid. 
I've never worked with a Hitatchi VFD so can't comment what's normal or not.


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## LVLAaron (Jul 4, 2022)

This is the auto-tune process. The motor barely turns and the VFD gives a failure... I press "stop" on the vfd and the software pops up with it's values, which match hitachi default... presumably because auto-tune failed.


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## DavidR8 (Jul 4, 2022)

I have to wonder why autotune won't run. That seems like a good place to start.
Have you been in touch with wherever you bought the VFD?


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## woodchucker (Jul 4, 2022)

did you make sure every wire is tightly bound.


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## mksj (Jul 4, 2022)

If the motor longer will auto tune with the belts off than suggest a motor problem. You can also try to do the motor auto-tune statically and if that fails then the motor is probably bad.


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## LVLAaron (Jul 4, 2022)

mksj said:


> If the motor longer will auto tune with the belts off than suggest a motor problem. You can also try to do the motor auto-tune statically and if that fails then the motor is probably bad.



Static tune also fails. 







This would explain the chattery gears. 

I guess I'll call PM tomorrow.


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## mksj (Jul 4, 2022)

Yes, it appears the motor is bad, like one phase is not working correctly, and also explain that the Auto-tune does fails on both static and dynamic. Unfortunately there is no off the shelf replacement options. The Marathon E470 is about the only motor that fits in the space and requires a new motor mounting plate, there are various postings and designs in other threads. Jake was able to install a Marathon vector motor but was a particular short body version and the belt tension is set with a turn buckle attached to the cabinet. Overall the motor  space and attachment on these lathes are very poorly designed. Just double check all the motor wire connections are tight.


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## LVLAaron (Jul 4, 2022)

Crap. 

I'll double check all the connections and do some continuity tests...


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## LVLAaron (Jul 4, 2022)

U2
V2
W2nanaU5
U1
Line 1V1
V5
Line 2W5
W1
Line 3


All wiring secure. 
Above is a table of the motor wiring... I dont know much about 3 phase motors but it feels like I have a burnt winding. 


Continuity test: 
U1 to V1 = pass
V1 to W1 = fail
U1 to W1 = fail
W1 to W2 = pass
U5 to W5 = fail
W2 to V2 = fail


Looks like something is wrong with Mister W, yeah? 

Is it worth cracking the motor open to see if it's something obvious?


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## Dabbler (Jul 4, 2022)

To avoid $$$ it is worth a try to demount and check inside.  Redoing all your connections would also be wise.


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## LVLAaron (Jul 4, 2022)

Dabbler said:


> To avoid $$$ it is worth a try to demount and check inside.  Redoing all your connections would also be wise.



It's certainly still under warranty as it's only 6 months old... but I'm afraid I'll have to wait for a motor to arrive on a slow boat from Taiwan. 
I'll pull it apart in the morning and see if something obvious is going on .


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## Just for fun (Jul 4, 2022)

Well, that's a bummer.  I guess if the wait is too long on the slow boat there is always the option that Mark mentioned.






						Marathon 3 Hp Severe Duty Motor, 3 Phase, 1800 Rpm, 230/460 V, 182T Frame, Tenv E470 | Zoro
					

Order Marathon 3 Hp Severe Duty Motor,  3 Phase,  1800 Rpm,  230/460 V,  182T Frame,  Tenv, E470 at Zoro.com. Great prices & free shipping on orders over $50 when you sign in or sign up for an account.




					www.zoro.com


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## fixit (Jul 5, 2022)

Maybe remove the motor and get an estimate from a motor repair shop.


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## LVLAaron (Jul 5, 2022)

Just for fun said:


> Well, that's a bummer.  I guess if the wait is too long on the slow boat there is always the option that Mark mentioned.
> 
> 
> 
> ...



That thing's a heffer for sure.


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## wachuko (Jul 5, 2022)

LVLAaron said:


> It's certainly still under warranty as it's only 6 months old... but I'm afraid I'll have to wait for a motor to arrive on a slow boat from Taiwan.
> I'll pull it apart in the morning and see if something obvious is going on .


Still, you should call PM and get the replacement under warranty... even if you decide to get a different motor, you will still have a working backup motor...


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## Beckerkumm (Jul 5, 2022)

Ebay has a listing for that short length marathon blue max motor for $300.  If I had that lathe I'd jump on it as an extra.  Dave


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## LVLAaron (Jul 5, 2022)

Beckerkumm said:


> Ebay has a listing for that short length marathon blue max motor for $300.  If I had that lathe I'd jump on it as an extra.  Dave


If we're looking at the same thing, it's a high RPM motor.


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## Beckerkumm (Jul 5, 2022)

My bad.  Thought this was the one i had seen a few months ago.  Should have looked.  Dave


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## LVLAaron (Jul 5, 2022)

I'm definitely not a motor expert, so don't judge me here... I was testing (U1 to V1,V1 to W1 ,W1 to U1) and getting different results from last night. 
It's very sporadic, Sometimes, I'd get continuity every 120 degree rotation of the shaft (i dont know if that's normal? I dont think so!?) and sometimes nothing at all.

Anyway, called PM and shared this thread with them. Sounds like they have a motor.


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## mksj (Jul 5, 2022)

Continuity should not change with motor rotation, so most likely one of the windings is bad and it appears intermittent. It is not worth rewinding the stock motor given the costs these days. I would speak to PM/QMT first and then decide what your options are after that. There are a couple of Marathon Y541A listed on eBay that are the same as Jake P used, but requires a new motor mount and a number of other modifications to the cabinet and belt cover. Not a small undertaking and may need some welding to incorporate the hinge.  The E470 you would need to shop around for pricing, but they are up ~25% from about a year ago. The "Y541A" is probably a better motor, but both require a lot of work to get them to fit.









						1440GT Upgrades and Additions
					

Part One, VFD Conversion:  As some of you may remember I had a 1340GT on order for many months and ended up finding a deal on a  used 1440GT just before my 1340 was to be delivered.  The thread with that story is here:      https://www.hobby-machinist.com/threads/my-1340gt-story.95922/  Since...




					www.hobby-machinist.com


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## LVLAaron (Jul 5, 2022)

mksj said:


> Continuity should not change with motor rotation, so most likely one of the windings is bad and it appears intermittent. It is not worth rewinding the stock motor given the costs these days. I would speak to PM/QMT first and then decide what your options are after that. There are a couple of Marathon Y541A listed on eBay that are the same as Jake P used, but requires a new motor mount and a number of other modifications to the cabinet and belt cover. Not a small undertaking and may need some welding to incorporate the hinge.  The E470 you would need to shop around for pricing, but they are up ~25% from about a year ago. The "Y541A" is probably a better motor, but both require a lot of work to get them to fit.
> 
> 
> 
> ...



That's actually a pretty clean install. No need to take the backsplash off to adjust the belt tension!
I thought the continuity thing was screwy. Sounds like I'm in luck with a PM motor. Don't know if they'll want the old one back but it'd be worth it to have a spare. I love spare parts.


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## LVLAaron (Jul 5, 2022)

off topic - what kind of sealant should I put on the headstock cover? gray permatex?


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## Just for fun (Jul 5, 2022)

The stuff I used was gray, designated for gear oil.


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## LVLAaron (Jul 5, 2022)

PM has a motor on the UPS truck for me. 

Thanks for the sanity check and shoulders to cry on.


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## ddickey (Jul 5, 2022)

Isn't there a gasket?


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## LVLAaron (Jul 5, 2022)

ddickey said:


> Isn't there a gasket?



Mine had a tiny bead of some kind of RTV.


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## Stonebriar (Jul 5, 2022)

This is what I used when I changed my oil.  And by the way that ISO 68 Mobil oil is now $59 a gallon. WOW



			https://www.amazon.com/Permatex-22074-6PK-High-Torque-Silicone-Gasket/dp/B004WJPO2E?th=1


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## LVLAaron (Jul 5, 2022)

Still 29 on PM's site... Got a few gallons just in case.


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## Just for fun (Jul 5, 2022)

This is what I used.  I already had it on my work bench.   I probably got it at the local auto parts store. 





__





						Permatex Permatex Auto Gear Oil RTV Sealant 3 oz carded tube (81182) | Zoro
					

Order Permatex Permatex Auto Gear Oil RTV Sealant 3 oz carded tube, 81182 at Zoro.com. Great prices & free shipping on orders over $50 when you sign in or sign up for an account.




					www.zoro.com


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## LVLAaron (Jul 6, 2022)

Me waiting for UPS to bring me my new motor and some treats for my dogs.


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## LVLAaron (Jul 7, 2022)

New motor did not resolve anything 

Same weird cogging, not able to auto-tune. 
I've double checked all settings on the VFD. All the same as always, as suspected, nothing was changed when it stopped working. 

I guess that's the next thing to swap out.


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## ddickey (Jul 7, 2022)

@LVLAaron What is your carrier frequency set at? Have you tried to change it?


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## mksj (Jul 7, 2022)

Haven't seen that before and I do not follow the intermittent motor continuity. I would do a factory reset on the VFD, and then reprogram it.


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## LVLAaron (Jul 7, 2022)

I "re-initialized" the VFD. I don't believe there is a "factory reset" option...

Double checked all settings... all where they should be and have been since day one. Still won't auto-tune.

New VFD showing up tomorrow... if that doesn't work I will be at a complete loss.


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## xr650rRider (Jul 7, 2022)

The VFD would normally show some kind of fault code.  Sounds like motor is trying to single phase or getting a high frequency noise on frequency input if it's hunting.  You should be able to see phase voltages, currents etc with software.  You have any other VFD's running? Without line reactors or isolation transformers, VFD's reflect noise back on input lines but normally doesn't cause any issues.

If you have the multi-meter set on ohms you should be reading the winding resistance or infinity if they are open, 0 if shorted.  Check lead to motor case and if it reads anything your getting a ground fault.  Again the VFD would fault and display a code.  Keep your fingers off the leads as often times a multi-meter can pick up the bodies internal resistance.


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## LVLAaron (Jul 7, 2022)

No fault codes. (I got some overvoltage type errors when I was freespinning the motor). I have a cheap EFI filter on the electrical going into the lathe. Voltage is 242 and even across both legs.


Where would I see the voltages and current info? I'm only familiar with Pro Drive Next and don't see anything in there.


No other VFD's running, ever. The only real electrical changes around here are some new transformers on the neighbors houses.


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## xr650rRider (Jul 7, 2022)

I'm not that familiar with the software for monitoring either.  I ASSumed that it would monitor those registers.  Usually just modbus registers.  Last software I was using was for servo on ELS and could monitor most parameters while it was running in realtime.


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## ddickey (Jul 7, 2022)

Is it a wj200?


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## LVLAaron (Jul 7, 2022)

ddickey said:


> Is it a wj200?



Yes


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## Dabbler (Jul 7, 2022)

It is just possible that one of your IGBT transistors is buggered.  Spinning up a lathe with chuck and work can put quite a strain on a VFD, and its output transistors.


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## ddickey (Jul 7, 2022)

b083 is the code for carrier frequency. You can try setting it at 2khz and see if there is any change.


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## mksj (Jul 7, 2022)

Hitachi Drives – WJ200 Series Restoring Factory Defaults

    Press ESC to show function code “d001“
    Press ESC three more times to show “b001“
    Press UP arrow key to change function code to go to B084 (“b001” → “b084“)
    Press SET to display current value of “00“
    Press UP arrow key to “02” then press SET to save data and initialize parameters.
    Press UP arrow key to change function code to go to B180 and set to 01 and hit set.

Initialization should start and when completed should show d001.

I would change the motor parameters and then try to run the Auto-Tune, if it fails then it suggests a VFD failure issue. But surprised you do not get an error  code with an output IGBT failure.


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## LVLAaron (Jul 7, 2022)

mksj said:


> Hitachi Drives – WJ200 Series Restoring Factory Defaults
> 
> Press ESC to show function code “d001“
> Press ESC three more times to show “b001“
> ...



That's the initialization I did. It did show d001 afterward. The only thing I have left to try is changing the carrier frequency but at this point it's probably a lost cause.
We had some bad storms a few weeks ago... My transformer was sparking and all of my GFCI's were tripped... I had the lathe powered off by a disconnect switch but I'm wondering if something didn't sneak into the VFD


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## Dabbler (Jul 8, 2022)

LVLAaron said:


> but I'm wondering if something didn't sneak into the VFD


Sounds like it.


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## rabler (Jul 8, 2022)

If a contactor between a motor and VFD can damage a VFD, it seems quite likely an intermittent continuity on one motor winding could also do so.  It sounds to me like that is what happened to yours.  Keep in mind that interrupted current through a coil is how old ignition systems worked, and a winding is similar to a coil.  I’d suspect that more than the electrical storms.


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## LVLAaron (Jul 8, 2022)

When in doubt, rip it out.


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## LVLAaron (Jul 8, 2022)

UPS brought me a new VFD this morning! Swapped it out... programmed it.. Auto-tune worked! - I get a really slight bit of cogging when it first spins up, I'll have to play with that, and maybe swap back to the old motor, or maybe one of you smart guys knows what settings to tweak.
But we've made progress in the right direction.


It started pouring rain, so I can't hear anything in the shop and there's lightning so it's all unplugged for a while.


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## BGHansen (Jul 8, 2022)

Glad you're 99% of the way there!  As my wife and I are fond of saying to each other, "Isn't it great when sh*t just works!".

Bruce


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## Just for fun (Jul 8, 2022)

Alright, good news.

Mine does a little cogging or hasatation when when I start it but I only notice it when I have the speed turned down real slow.  I'm not sure if thats the same thing you are experiencing or not. 

Tim


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## ddickey (Jul 8, 2022)

You can try to increase your minimum Hz a little.


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## LVLAaron (Jul 8, 2022)

It might be just being ultra sensitive to everything right now, and having the backsplash removed... but the new motor is a little less smooth and more noisy than the old one... Saturday I'll put the OG motor back on and see how she works.


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## LVLAaron (Jul 8, 2022)

ddickey said:


> You can try to increase your minimum Hz a little.



This?


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## Dabbler (Jul 8, 2022)




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## LVLAaron (Jul 8, 2022)

Changing to "Constant torque" instead of "sensorless vector" smoothed it right out.


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## mksj (Jul 8, 2022)

You should be able to run in sensorless vector which uses feedback from the motor poles to optimize performance. If it operates in constant torque (V/Hz) w/o sensorless vector then you loose performance below 30 Hz and also at the higher Hz. The stock motor stutters on acceleration, this is a known issue with the 1440GT motor, it is decreased by shortening the acceleration to 2-3 seconds and setting the acceleration to linear as opposed to S curve. A usable speed range for the motor is 20-100 Hz. This all doesn't explain why the motor was previously fine and then you started having the motor issues.


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## LVLAaron (Jul 8, 2022)

mksj said:


> You should be able to run in sensorless vector which uses feedback from the motor poles to optimize performance. If it operates in constant torque (V/Hz) w/o sensorless vector then you loose performance below 30 Hz and also at the higher Hz. The stock motor stutters on acceleration, this is a known issue with the 1440GT motor, it is decreased by shortening the acceleration to 2-3 seconds and setting the acceleration to linear as opposed to S curve. A usable speed range for the motor is 20-100 Hz. This all doesn't explain why the motor was previously fine and then you started having the motor issues.



Makes sense. I will continue to fiddle with it. The type of work I do, I'm usually in the 50-80hz range. The only time I've really deviated from 60hz is when using a carbide chamber reamer and "tuning" the chatter out.


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## LVLAaron (Jul 11, 2022)

Update for posterity - I called Drives Warehouse to see about a warranty replacement. 
Their support/sales line was great. Someone picked up immediately and knew everything about this inverter, settings, etc. Based on what I told him 
he said it does sound like VFD lost an output or one of the IGBT's isn't working correctly. He also said there is an IGBT test that can be run, but since it was out of the cabinet already, no need to. 

Long story short... if you're having trouble and purchased from these guys, dont hesitate to call!


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## LVLAaron (Jul 11, 2022)

Also, I'm using a 5k pot as described in the PDF floating around here (PM1440GT Basic Wiring Changes for using the Contactors to switch the VFD inputs 23 DEC 2018.pdf)
Engineer said I should be using a 2k pot.


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