High start & run AMPS on a Craftsman (DeVilbiss) Air Compressor

I have a Craftsman Air Compressor made by DeVilbiss that has HIGH starting and running AMPS problem that often throws the 20A breaker at startup.

Specs:
Craftsman 150psi, 25gal oil-lubed horizontal Compressor, dual-piston.
GE 2HP 15/7.5A capacitor motor, # 5KCR49UN2398AY set for 120v operation.
10g wire dedicated supply, 10g power cord.

My "Kill A Watt" meter tells me that it pulls 26 AMPS when start and 18 AMPS running. Voltage is 120v. This compressor often trips the 20A breaker at startup, even at the lower psi cut-in.

I have checked the wiring per the motor label and it is set for 120v. Label only shows line in and the positions of T2 and P2 for 120/240 operation. There is no reference for the other wires at the wiring block so I assume they are correct.

I can't figure out why the HIGH AMPS? Bad motor? Capacitor? Stuck in START windings?

This was a brand new compressor 3 years ago and is rarely used. It had this hard start problem when I bought it but I thought it was just my wiring (10g wire at 75 feet from panel) so I didn't return it to Sears nor did I check the amps. Now I need it for a workshop build (air tools) and this high amp problem is now a BIG PROBLEM.

Any advice? Besides Beer 4U2

Robert

 

Don't think it's stuck in start windings or it would have burned up long ago. Since you say you always had this problem, I suspect the endplay on the pump crankshaft was set incorecctly at the factory. Ever try to rotate the pump by hand? Should be easy; if it isn't - something is sticking in the case. Other than that, an overtightened belt will overload the motor.. bad motor or pump bearings will do the same. Double check all your electrical connections, especially quick connects. BTW, what's the safety factor of the motor? Cos if it's over 1.15, you may be okay on the amp draw.

 

UPDATE:

I did more troubleshhoting on it....

Without any load on the motor (belt removed) the amps are exactly as the label designates: 15/7.3A
When I add the compressor without air outlet connected: 19A start & 9.8A running
With air outlet attached and with 80psi in tank: 26A start & 16.5A running

The SF is a 1.0 on this motor.

Check valve works perfectly as does the air bleed off.

Maybe this is why Sears now uses the 1.8HP motor instead of the 2HP I have on mine? Too high amps kicking out peoples 20A breakers...

The compressor spins BY HAND ON PULLEY with minor effort but I would not call it an easy spin... It is moving two pistons after all... Not sure if it is within specs or not...

Seems I may just need to up my breaker to 30A after I check my length of wire calculations for the 10g wire I have supplying the compressor.

Robert

 

You're golden. I have a 5 horse Baldor on mine that jumps right into the service factor and over it slightly towards the end of a cycle. Been running that way forever, never hurt it. So go ahead and up the breaker. If it really bothers you, the only "cheap" (and good) thing you can do is slow the pump down a little by changing the motor drive pulley to a smaller size. That'll knock the amps down for sure but you'll lose some cfm. Good luck.

 

Robert
I had a similar problem on a motor here. It burned up receptacles,cords,centrifugal switches,tripped breakers at start up. I finally changed from 120 volt to 240 volt.. converted the circuit and have not had a problem since.
While it might be convenient to run machines on 120 volt its hard on plugs,switches,caps and breakers. By changing to 240 volt it also balanced the load panel. I think your should give thought to changing over to 240 volt if you have spare circuits in panel.