Help Please: Motor Maintenance

carbonsteel928

carbonsteel928

Joined
Feb 15, 2010
Messages
696
After a LONG four days of "white glove," cleaning my shop and doing yearly maintenance on every piece of equipment and tool I find myself with a persistent problem with one of my Leeson 2hp 3ph motors. I took it apart to retrieve the ground screw which fell in while trying to attach the ground wire, and though this is quite a simple task in itself, it now produces a very high-pitched whine. Normally it would not be an issue as hearing protection is always worn but it is loud enough to penetrate my Surefire Sonic Defender ear plugs.

Since it did not make this horrid sound prior to being taken apart, I now fear that it was a result of my "maintanence." If you guys have any ideas on how to troubleshoot this very annoying issue, it would be great appreciated. Thank you in advance.

-Mike
 
Did you remove just the rear endbell? Are all the phase conductor connections tight again? Does it run hotter than normal? Is this a belt driven machine, if so how are pulley condition, belt condition, and alignment?
 
Hugo, its driving my 9" disk grinder. I removed the rear and replaced everything as it was. The high pitch whine seems to remain constant regardless of the speed or vfd input. As for the heat, I have no way of telling. It seems warmer to the touch but I've read that expelled heat on the housing is no indicator. Thanks.
 
I wonder if the whine goes away when you remove the ground connection again?? You were running before without the ground connected right? Not saying that it is proper to run with an ungrounded motor but this might help in troubleshooting.
 
I thought of that, and tried it but nothing changed. I'm wondering if maybe removing a small screw found in the mount may have disconnected or allowed something to shift. I have no idea why in the world I removed that damn screw either. After removing it, it was replaced immediately upon becoming aware of my actions.
 
When you put the endbell back on did you hammer it so the bearing would seat (also not recommended)? Perhaps the rotor shifted too far forward and it is off magnetic and mechanical center? Is the frequency of the whine the same at all speeds? Is it the same at 100 rpm as it is at 3000 rpm? What about the amplitude? Is it as loud at 100 as it is at 3000?
 
Make sure the fan is not rubbing, either on the motor itself (fan on to far) or on the shield, (not on far enough)

Im also curious to know if the sound varies with the speed
 
Hugo, I didn't hammer it back together, but I did use a wooden mallet to remove the endbell. The frequency and noise level is the same at all settings. Thanks for the tips, I would have never considered them without help. :D
 
Hugo, I didn't hammer it back together, but I did use a wooden mallet to remove the endbell. The frequency and noise level is the same at all settings. Thanks for the tips, I would have never considered them without help. :D
 
How does the motor turn over by hand? Nice and easy? In your maintenance did you do anything to the vfd?
 
Hugo, thank you for the help. Luckily the motor is still under warranty and there is a service center a few miles down the road. Their tech had the same thoughts of you and asked that I bring it into their shop.

Thanks again.
 
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