PM-1127VF (not a Precision Mathews) lathe issue

M

mlchman

H-M Supporter - Silver Member
H-M Supporter - Silver Member
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I bought this lathe used. It worked great for about a year. The other day I fired it up and it went full speed and then tripped the GFI breaker. I turned it off but every time I plugged it in, with the switch off, it tripped the GFI. I waited a day because it was late. Now it will turn on but it spins at about 1040 RPM on the low range pulley setting. Rotating the speed control knob does not do anything. I called the tech support line for Precision Mathews and sent them a picture of the machine. It looks identical except no Precision Mathews logo. He said it wasn't one of theirs so he was unable to assist me.

I am at a loss as to where to start. Has anyone run into this problem? Any suggestions?

Thanks in advance

Mlchman
 

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  • PM 1127VF.jpg
    PM 1127VF.jpg
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If you are tripping the GFI, you have current flowing where it shouldn't. Makes me think that your VFD has an issue. If it's as similar as it looks, there is a cover on the back behind the control panel. The VFD is in there. Perhaps try disconnecting the motor leads and plug it in. It could be a short in the motor. Though I would expect the VFD to detect it and shut down. Perhaps the GFI is just faster. You can get VFDs on ebay that will do the job and won't kill the wallet.
 
ttabbal said:
If you are tripping the GFI, you have current flowing where it shouldn't. Makes me think that your VFD has an issue. If it's as similar as it looks, there is a cover on the back behind the control panel. The VFD is in there. Perhaps try disconnecting the motor leads and plug it in. It could be a short in the motor. Though I would expect the VFD to detect it and shut down. Perhaps the GFI is just faster. You can get VFDs on ebay that will do the job and won't kill the wallet.
Click to expand...

I don't think it has a VFD, it has a Speed Control Board (same thing?). The lathe turns on and runs fine, it just runs at full speed with no speed control.
 

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  • Speed control board.jpg
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Ahh, DC motor. Yeah, probably just need to replace that controller. Not sure what to suggest other than see what people are using for that. Treadmill motors being used for other things usually need a control like that. 90VDC, usually PWM.
 
Well, if there's a problem controlling the speed I think you've found the problem. Does anything look burnt on the board? There are plenty of 0-90v speed controllers out there but a good one that will work at the maximum amperage stated on yours will cost you. What HP is the motor?

John
 
If it isn't really a PM lathe you might check with Dro-Pros, they are a Weiss distributor in Northern California. PM says theirs are not the same as Weiss, but they look nearly identical, so maybe that is what you actually have with a weird label on it. Since Dro-Pros sells Weiss, then if it is a Weiss maybe they can help you.

The 11x27 would compare to the Weiss WBL290F

https://www.dropros.com/DRO_PROS_Weiss_Lathes.htm


Grizzly's 11x26 looks very different, so probably safe to rule that out.

It is weird that the warning label appears to be in English, German and Dutch.
 
I'm at a complete loss as to how a lathe labeled "PM1127VF is NOT a Precision Matthews machine. However when my 1127VF was new I found the factory speed controller to be really weak, and in addition, if you switched from F to R at speed, you could blow it up. I replaced mine with a KBMG-212D from Galco Industrial (https://www.galco.com/buy/KB-Electronics/KBMG-212D) which I've used daily for 10 years and greatly prefer it. The wiring is actually simpler- the F/R switch is no longer reversing DC motor current but instead just switching a signal voltage to the controller. Mom importantly it has BRAKING and adjustable acceleration. You can switch from F to R at full throttle and nothing bad happens. I've attached the docs I wrote 10 years ago.....
 

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  • KBMG-212D Speed Controller Upgrade notes V1.1.pdf
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  • PM 1127VF Motor Controller Upgrade Schematic V2.pdf
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Call PM back and tell them that it is indeed a Precision Matthews lathe. If you have a look at the wayback machine, their website from 2012 shows the 1127-VF without a PM logo on it.

PM1127VF Lathe

Precision Matthews PM1127VF Metal Working Lathe has Power Cross Feed, and has Variable Speed. Large Accessory Package.
web.archive.org

I also found another site where someone received a PM-1127 from Precision Matthews and it did not have a logo either.

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Your machine is almost certainly out of the 3 year warranty period, but they should still be able to provide guidance on troubleshooting, how to resolve once the problem is identified, and either provide a replacement part (You'll need to pay for it though, again, not in warranty) or at least provide details on what needs to be replaced so you can source it yourself.
 
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