# Adding a capacitor



## gnxtc2 (Feb 21, 2011)

My generator has a 30A/120v main breaker on it (no 240v is available on the generator). I have a Crapsman 120v 5HP 25 gal oil free air compressor. I think Crapsman rates 5HP as start up current. When I plug in the air compressor, it trips the breaker on the generator. The compressor runs fine on utility power. 

I put my clamp on meter on the compressor. At start up, the amps jump up to 50A and start coming down as the begins to run. As the amperage begins to drop, the breaker trips. I doubt the breaker on the gen set is HACR rated. I don't feel like taking apart the generator to replace the breaker.

Is it possible to wire in a start up capacitor to ease the start up current? If so, what size capacitor do I need and does it go in series with the hot leg? If anyone has schematic it would help.

Thanks

Billy T.
[email protected]


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## JRaef (Mar 23, 2009)

gnxtc2 said:


> My generator has a 30A/120v main breaker on it (no 240v is available on the generator). I have a Crapsman 120v 5HP 25 gal oil free air compressor. I think Crapsman rates 5HP as start up current. When I plug in the air compressor, it trips the breaker on the generator. The compressor runs fine on utility power.
> 
> I put my clamp on meter on the compressor. At start up, the amps jump up to 50A and start coming down as the begins to run. As the amperage begins to drop, the breaker trips. I doubt the breaker on the gen set is HACR rated. I don't feel like taking apart the generator to replace the breaker.
> 
> ...


No, if it is a 120V motor it already has a starting capacitor, adding more will not help. Your generator is too small to start that motor.


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