Craftsman 6HP 33 gal unit compressor blows fuse

by Darren
(Hopkins, MN)

I have a 7 year old Craftsman 6HP 33 gal unit that worked fine until the other day.

The compressor will run for about 2 seconds then blow the fuse.

I disconnected the feed lines to the tank and get the same result.

Being the motor spins it doesn't appear to be siezed. What other tricks can I try before I junk it?

__________________
Bill says...

You removed the line from the pump to the tank, and that should have unloaded the piston. If the tank isn't empty of air, reattach the line, and dump the tank air anyway, and try to start it again.

I'm suspecting a start capacitor issue, but I need you to rule out the unloader valve first.

Cheers,

Bill




Comments for
Craftsman 6HP 33 gal unit compressor blows fuse

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Jan 19, 2012
 Thanks
by: Anonymous

Wow your advice for the most part useless. Advice: spend money and replace everything.. Thanks for your expert advice. Not!!!

__________________

Worth every penny you paid for it, chum!

B.
Nov 14, 2011
 Same 6hp oil less compressor and problems
by: Brian H

Mine starts but does not come up to a high enough speed to drop out of the start windings. The unit is free spining, even unhooked the piston and tired it. Checked both the start and run cap. Both good. The compressor will run till the breaker trips or the overload on the motor trips. Pulling 25 - 30 amp on 120vac twice the rated current. If I push the cyntrifical swith out the current increases but no change in the motor speed. Also checked the voltage at the motor termials during running and stayed at 120VAC the entire time thus no voltage drop on my circuit. Guessing the run windings may be bad but have no way of testing. No schematic on the motor.
Nov 10, 2011
 Tried replacing start capacitor
by: Anonymous

As title indicates, I tried changing start capacitor and problem does not change. I tried disconnecting the tank as well and that doesnt not help either.

Any suggestions?

___________________

The breaker pops or the fuse burns because there is too much current flowing through them. There are many things that could cause this including a marginal power supply (too many appliances pulling power from the same circuit) non-functioning unloader valve, failing capacitor, pump mechanically overloading the motor, a run capacitor failing, a motor shorting out.

If the capacitors are fine, the pump is fine, then you need to get the motor load tested, in my opinion.
Nov 03, 2011
 Start Capacitor
by: Anonymous

I am having the exact same issue. My compressor keeps blowing the fuse. When I remove the cover from the switch, and turn the compressor on and off, I see lots of spark when the switch makes contact. The piston will turn but the compressor will not start going normal speed, it will start for a few seconds then blow fuse.

Where is the start capacitor located? In black box where the "pressure switch" is located? (looks like a coil from a car distributor)?

_____________________

The start and run capacitor are usually on the motor itself, a cylindrical bump on the motor housing. Depends on the compressor, of course.
Jul 27, 2011
 Confirmed
by: Darren

I did initially completely empty the tank before disconnecting the line.

________________

OK. Sorry it's not the unloader valve, as that's likely a lower cost fix. As I noted in the earlier post "I'm suspecting a start capacitor issue" and you need to get it tested. Might as well get the motor load tested at the same time.

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