(Yet Another) Tired Air Compressor

[rcsec]

(If there is a dedicated air compressor thread that covers all this, please let me know.)
I horse traded for a Speedaire (Grainger brand) air compressor:
3Z428B 2HP
Motor = Dayton 9K328G
Compressor = 2Z499A

When I got it the motor wouldn't cycle on, checked the pressure switch and one side wouldn't pass current. I shot cleaner through the contacts & blew them out - still had trouble passing current (high resistance.) I filed the contacts and resistance was all but 0. I ran for a couple of minutes just to blow out the tank. Now it trips a 20 amp breaker (no other loads on that line.)

Since the contacts (in the pressure switch) look like donuts (verse a shiny little dome). Is time for a new replacement pressure switch & is a generic available? Is there a different test I should try?
Thanks,
Ray

 

[Outlawmws]

As a test of the motor itself, try bypassing the pressure switch entirely, and just use the plug as the on off switch. if it still trips the breaker, then it's likely the motor or the cords are too high of resistance (Fried copper...), or the breaker is out of spec.

Have you tried another circuit to make sure it's not the CB?

 

[rcsec]

I haven't tried the motor by itself but have tried it on another line - kept tripping the GFI. The power cord is 10 AWG.
thanks,

 

[Stuart in MN]

120v or 240v? If it's set up for 120v and the motor is a true 2hp, it will trip a 20 amp breaker.

 

[rcsec]

Yeah, right on the edge for 110 and I was ready to run a dedicated 220 line. Since it's kicked on just a couple of times I can check the resistance across the pressure switch again...and see how it behaves without the belt hooked up.
thanks,