Noisy Motor

[Mark Gibney]

The motor on my disc / belt sander runs smoothly and quietly on 120 volts, but is loud and harsh sounding on 240 volts.

489575 489576

It's a little dual voltage 3/4 hp motor.
I double and triple checked my wiring for 240 volts, had my buddy check it too. Everything is in order. I took the back off the motor, the centrifugal switch looks good, I blew out any dust in there (very little). The capacitor looks good. Still runs noisy as hell on 240.

Any ideas what's going on?
thanks, Mark

[Greg Quenneville]

Is your 240v circuit wired correctly? I have heard of dual voltage motors being noisy when connected to the wrong (lower) voltage.

[Lee Schierer]

The motor on my disc / belt sander runs smoothly and quietly on 120 volts, but is loud and harsh sounding on 240 volts.

489575 489576

It's a little dual voltage 3/4 hp motor.
I double and triple checked my wiring for 240 volts, had my buddy check it too. Everything is in order. I took the back off the motor, the centrifugal switch looks good, I blew out any dust in there (very little). The capacitor looks good. Still runs noisy as hell on 240.
vel.
Any ideas what's going on?
thanks, Mark

I believe your link belt is on backwards. Those little tabs on the inside of the belt should lean back in the direction of travel. If that motor is rotating clock wise as you look at the motor from the v shaped slots should have the narrow end pointing down in your photo that show the belt.

[Mark Gibney]

Greg, yes the 240 V circuits are wired correctly, other machines run perfectly on them.
Lee, the motor runs counter-clockwise. But I like your attention to detail!

[Cameron Wood]

Check that the male plug end is wired correctly?

That is quite a tiny pulley- wouldn't explain the issue, but I imagine that they (other pulley is also small?) would be more noisy.

On my machine like that, and the motor pulley is 5"

[Brian Runau]

Here's a link to minimum recommended pulley size by motor HP.

https://www.bestorq.com/info/NEMA.htm

[Zachary Hoyt]

If you take off the belt is it still noisy? That would eliminate the belt and pulley from the discussion.

[Mark Gibney]

The motor is still noisy without the belt on.
That pulley is sized correctly for the machine it powers.

[Mark Gibney]

To re-iterate - it runs quiet on 120 V, noisy on 240.
Other machines run fine on 240 on the same circuits.
All the wiring is good.

[Lee Schierer]

To re-iterate - it runs quiet on 120 V, noisy on 240.
Other machines run fine on 240 on the same circuits.
All the wiring is good.

I would switch it back to 120 power, there is no difference in performance between the two voltages unless your wiring is under size for the 120 volt current it draws.

[Mark Gibney]

I am thinking of using it on 120, but the noise concerns me. Something is amiss and a stitch in time!
I might pop around to the local electric motor place and see if they can diagnose it.