KMG Help

S

SharpEdge0913

Joined
Oct 21, 2011
Messages
6
I am having an issue with my KMG that has a VFD. After 5-15 minutes of grinding the motor gets hot to the touch and it starts to stutter, skip, slow down, and sometimes stops completely. After the motor cools it will do the same thing after 5-15 minutes of running. I was convinced my motor was bad so I bought a replacement, hooked it up today, and have the same problems. So now I have 2 motors that I "think" are fine.

One variables is that I moved recently so it was disassembled and reassembled. I can't think of anything mechanically that would cause this. They are pretty straight forward to setup.

The motor(s) are both Leeson 110745 C6T34FB16F
The VFD is the standard from Beaumont, the KBAC-27D. It plugs into 110v.

Could there be an issue with the VFD that would cause that? Any ideas? I am at a loss.

Thanks,
Dan
 
What does the status indicator LED on the VFD say when your having this problem? Slow flashing green is normal operation.
 
Most of the time it will be flashing green during the problem but sometimes it will show red typically during the bigger slowdowns/stutters.
 
when it starts to do it next time, take the pulley off and see if it still happens. if it still does it, its the motor or the vfd. if it doesn't do it, its probably the bearings or something on the k m g.
 
What speed does it happen at, how hard are you pushing ?





Steady red is overload.

Running too slow, the motor fan runs slowly too and has insufficient cooling.


Do you also have the three step pulleys ?
If so put it in low gear, it will allow the motor to run faster with greater torque and cooling.




reproduce it on video if you can
 
I'm with woodster, check to see if there is a bearing causing a problem. If not the bearings, I'd call KB electronics. They have good customer service from what I've heard.
 
It was cooled from earlier so I just disconnected the belt and let it run on speed 50 (not sure how many rpms that is, but the dial on the VFD goes from 1 - 100, so half max) with just the pulley on the shaft. After about 5-10 minutes on speed 50 it started to get warm and stutter a bit. It seems to only do it at higher speeds, like 40 or above. It is a lot easier to see with the belt because you can see the wording on the belt change patterns from slowing down. Another issue, I am deaf, so I cant hear it. I can only look for visual clues or touch it.

This is my second motor, I just took the motor out of the box today and it is doing the same thing the previous motor was doing. If it is the motor, I would suspect either the VFD or the KMG setup caused it.

I'll see if I can get it on video.
 
Did you get them from Beaumont, or buy the components yourself ?

Find the setup instructions from Beaumont on how to adjust the settings for the vfd

Check that you have followed them.
 
I bought it as a package from Beaumont. I double checked the wiring and everything looks ok. It was running for a couple years fine until I moved and I only disconnected the wiring between the VFD and motor. I did not undue the wiring from the plug to the VFD. And I triple checked the wiring from the VFD to the motor.

Here is a video I just took of it. I never touched the speed dial and you can see it slow down in spots. I mentioned before, but I am deaf, so pay attention to any sounds as that could be clues I am not getting.
[video]https://youtu.be/5ocryA4hAFw[/video]

Thanks again for your help, much appreciated.
 
Last edited:
That sounds odd. I would take the belt off and run it for a while. Then try to grab the motor pulley with a leather gloved hand and put some load on it. See what happens. Call Rob, he will sort you out.
 
There is a high pitched squeal that comes and goes every half second or so. Hard to tell from the video where it's coming from, but something is surely wrong.
 
To me the squeal sounds like a bad bearing. If you tried two different motors then it must be on the drive wheel or one of the other wheels. If you disconnect the drive belt, and turn the wheels can you feel it grinding? Maybe someone could assist you in listening for a rough sounding bearing while hand turning them.
 
SharpEdge0913 said:
I bought it as a package from Beaumont. I double checked the wiring and everything looks ok. It was running for a couple years fine until I moved and I only disconnected the wiring between the VFD and motor. I did not undue the wiring from the plug to the VFD. And I triple checked the wiring from the VFD to the motor.

Here is a video I just took of it. I never touched the speed dial and you can see it slow down in spots. I mentioned before, but I am deaf, so pay attention to any sounds as that could be clues I am not getting.
[video]https://youtu.be/5ocryA4hAFw[/video]

Thanks again for your help, much appreciated.
Click to expand...

S.Alexander said:
To me the squeal sounds like a bad bearing..
Click to expand...

If it worked previously, it's possible there is a bearing getting hot and tightening up, or perhaps something got a whack on the move.

A mechanic would use a mechanical stethoscope to listen to each bearing to isolate the problem.
I read in this post above you're deaf, but You can do the same.

Find a long wooden broom stick like from a pushbroom.
Press the round end firmly against the cartilage above or behind your ear hole
Put the other end against the machine at each bearing

You won't so much hear it, as it vibrates your whole head.
Move it around for best use.
The bad bearing becomes really obvious.

It works great on isolating bad relays, solenoid valves, bearings, lots of things.


Especially check the tightness of bolts on bearings at the wheels.
 
I had the same problem. Try leaving the power switch on, power connected, not running, for at least an hour. After chasing down connections and other possible problems, that seems to have fixed it for me. According to the manual this reconditions the bus capacitors? Or something like that.
 
TILLER said:
I had the same problem. Try leaving the power switch on, power connected, not running, for at least an hour. After chasing down connections and other possible problems, that seems to have fixed it for me. According to the manual this reconditions the bus capacitors? Or something like that.
Click to expand...

I want to thank everyone for their suggestions and help. I started looking into everyone's ideas and tried TILLER's first because it is the easiest to try. That seems to have worked. After the bus capacitor reconditioning, I ran it with just the belt for 20 minutes and it did not get really hot or slow down. I ate dinner, went back out, and did some grinding for at least 30 minutes without any slowing issues. The manual says you have to do this if the VFD sits for a year or more. And it did sit for a year due to moving and some other issues, so that makes sense.

I am back to learning how to make knives :)
 
Wow, super easy and very in intuitive. Just goes to show that reading the manual can be helpful. I might just do that on mine.

For the electronic folks out there, what would be the explanation for what is going on during this reconditioning process.?
 
This thread is a BOMB!!!
I'm also curious about what happens with the capacitor, but this trick is a pearl for sure and i hope it will help many of us!!!
Very glad it worked!!
 
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