250 volt 3ph air compressor

[james g]

I have a customer that has a 250 3ph air compressor that keeps blowing up start capacitors every few months. What could be causing this to happen?

 

[ActionDave]

If it has start capacitors it's not three phase. It may have a three phase starter wired up to single phase.
How old is it? When did this start happening?
It could be a bad bearing in the motor, it could be a problem with the unloader for the compressor, it could be a loose connection in the circuit, or it could be a worn out starting switch in the motor.

 

[ptonsparky]

If it has start capacitors it's not three phase. It may have a three phase starter wired up to single phase.
How old is it? When did this start happening?
It could be a bad bearing in the motor, it could be a problem with the unloader for the compressor, it could be a loose connection in the circuit, or it could be a worn out starting switch in the motor.

...or the starter contacts are shot, or...

OP: 250 ?

 

[retirede]

Make/model/HP, or a picture of the nameplate would be helpful.

 

[tom baker]

250 v is an uncommon secondary voltage. I agree picture of nameplate would be useful

 

[Joethemechanic]

Assuming it's single phase, are you sure it's a starting capacitor? If you mistakenly replace a run capacitor with a start capacitor they don't last very long. Usually a start capacitor will be plastic, and a run capacitor will be metal.

Start



Run

 

[hillbilly1]

Abnormally frequent starts will also blow the capacitors. They either need to add tank capacity, or change to an air screw compressor.

 

[retirede]

Abnormally frequent starts will also blow the capacitors. They either need to add tank capacity, or change to an air screw compressor.

We have no idea what kind of compressor it is. Requested in post 4.