Grinder Motor Issues

Mike Gesualdo

Mike Gesualdo

Joined
Nov 11, 2012
Messages
220
Hey all,

Had my first afternoon back in the shop in two weeks... and of course I ran into an issue with my grinder. I was wondering if anyone more knowledgeable than I could help diagnose the issue, as I'm stumped. I'm using an Esteem grinder with a KBAC-27 variable speed, running off of 120V at 1.5HP.

It's been running it just fine for the past 10 months or so on the same outlet... there are no GFCIs, surge protectors, or anything. I was using it for a few hours today with no problems, turned it off to swap belts, and that's when I ran into the issue. It seems to start up just fine, and I can run it at low speeds... but it seems to cut out above a certain speed. I tried unplugging anything that was running on the same breaker, I tried a different outlet, unplugged it for a couple of hours... no luck. I quite honestly have very little experience with electric motors and VFDs, so I have no idea how to go about troubleshooting and/or repairing it (or knowing if I need to replace something :()

I took a video of the issue... pardon the dust:

[youtube]vflRJ7FWHyk[/youtube]

Here is the information on the motor:

ph7eKt2h.jpg


Any help on going about diagnosing the issue would be greatly appreciated, as I'm a bit at a loss of what to do! Happy to take any pictures I can.

Thanks!
Mike
 
Last edited:
I'm not familiar with the KBAC drives- and I've not had that problem with my VFD setups. I do know, though, that when I've had issues in the past, calling the service departments at Teco and at Vacon got me some friendly knowledgeable advice that helped a lot. You might try the same with KB electronics.
 
It's probably the potentiometer. If it is the open type you can clean it, if it is the closed type you will have to replace it.
 
John Moran said:
It's probably the potentiometer. If it is the open type you can clean it, if it is the closed type you will have to replace it.
Click to expand...

Just out of curiosity, what makes you think that? Trying to figure out the thought process behind it for future reference :) I'm guessing a dirty potentiometer would mean insufficient/irregular voltage, causing the VFD to cut off as a failsafe?

Going to call them and see if they can diagnose it more specifically first, but I'll give that a shot if all else fails. Thanks!

Mike
 
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