Single phase motor humming and heating up.

[i=p/u]

Hi, morning EF.

I was looking at a single phase motor yesterday attached to hydraulic pump for cardboard bailing machine that seems to be temerpemental with stop and starting and making humming sound.

I checked the contactor was working first and voltage was going to motor, I clamped the cable and was getting full current, with the motor not starting and humming and heating up very quickly. I just stopped and turned off so couldn't be used or touched.

I've just priced new motor and hydraulic pump and on reading further and thinking a little further, the capacitor is used as second phase to start up and then cuts off when running. I'm starting to think could the capacitor cause this and not even need new motor and pump.

Thx Trev.

 

[westward10]

Could be a few things and maybe not a motor issue but mechanical from the pump. Is it possible to run the motor with it isolated from the pump.

 

[i=p/u]

few pics.. well there we go, rating plate says 8.3A but when I clamp it, I'm getting 15 odd Amps which would suggest capacitor has kicked in, and with motor not starting not dropping down to the current rating.. hmmm..

 

[westward10]

Does the motor actually spin or is it locked.

 

[i=p/u]

No, it ain't spinning Westwood, just the humming.

 

[pc1966]

Can you get the fan cover off or otherwise see if the motor is mechanically locked or stiff?

A failed capacitor might explain the effect if the motor is free enough to rotate.

 

[westward10]

Replacing the capacitor is a cheap 'see if'.

 

[ian.settle1]

No, it ain't spinning Westwood, just the humming.

What tune is it humming, only joking, before you replace anything have you disconnected the hydraulic pump from the motor and tried running the motor on it's own?

 

[Lucien Nunes]

Bog standard symptom of failed capacitor. Of course failed capacitor can mean failed windings too but hopefully it hasn't got that far.

 

[i=p/u]

Well new motor and hydraulic pump came today, swapped it over, but now the up/down controls are not working, it will only go down if I hold in the contactor... so much for simple.swap