Troubleshooting Electric Motor Noise/vibration

[CarlosA]

I picked up a big old drill press recently, and when running the motor makes quite a bit of noise compared to a bench grinder or even my lathe motor. I had it all apart and replaced the bearings, used stronger bolts that are properly torqued, etc to stiffen it up. The sound is exactly the same after.

This happens whether the motor is hooked to the drill press, or on the bench. The noise is sort of like a hum or vibration and touching the motor you can feel a small vibration as well.

I`m not too familiar with the workings of AC brushless electric motors, but is there anything I should look for, or turn on my lathe that might help better balance the shaft?

Any ideas?

 

[kd4gij]

The centrifugal switch could be stuck in start mode.

 

[CarlosA]

The centrifugal switch could be stuck in start mode.

Ok just checked it and that thing is working good ... also removed it and started the motor by hand, same noise. Put it back together and watched it do its thing anyway.

 

[den-den]

There is not many parts involved. I would check the fan closely, it is usually easy to fix. If not the fan must be either bearings or armature balance.

 

[JimDawson]

Bad winding?

 

[Techie1961]

Could be the armature is loosening up. Have a look at the laminations and see if there is any evidence that it isn't tight.

 

[tq60]

Spin it up with a drill or something else handy.


It could be an out of balance issue that would make noise with drill but if quiet then could be bad winding like a broken wire on one of the poles.

If it is dual voltage and wired 120 there are 2 sets of windings in parallel.

You can open one at a time to see if it gets better.



Sent from my SAMSUNG-SGH-I337Z using Tapatalk

 

[CarlosA]

Spin it up with a drill or something else handy.


It could be an out of balance issue that would make noise with drill but if quiet then could be bad winding like a broken wire on one of the poles.

If it is dual voltage and wired 120 there are 2 sets of windings in parallel.

You can open one at a time to see if it gets better.



Sent from my SAMSUNG-SGH-I337Z using Tapatalk

Alright will try this .. it is wired this way. Two sets are wired up with the two single wires leading out to switch.

 

[David S]

when you are testing the motor on the bench, is there a big pulley on the motor shaft. Or is it just the motor and plane shaft?

David

 

[CarlosA]

when you are testing the motor on the bench, is there a big pulley on the motor shaft. Or is it just the motor and plane shaft?

David

Tested with and without pulley.