Air compressor problem

Joined
Oct 11, 2004
Messages
106
Location
upstate n.y
I recently purchased a new/used craftman air compressor from a yard sale, The guy I bought it from said he bought it 4 years ago and has never used it because it would keep blowing the circut breaker in the garage upon start up. and he just never got around to returning it or repairing it. I bought it and brought it home and sure enough it will blow the circut breaker in my garage circut box within 5 seconds, and the pipe gets very hot in that length of time. The compressor is an electric 120 volt, 15 amp with a 6 hp motor and a 33 gal tank, The circut I tried it on has a 20 amp circut breaker that I also I swapped out just in case of a bad one and still the same problem, also the circut has nothing else drawing from it, It only has 1 plug on it that is above my work bench. Any Ideas as to what the problem could be?
 
Joined
May 26, 2003
Messages
9,832
Location
Central Coast, Calif.
does it spin before tripping the breaker? if not then something is keeping the motor from spinning. You'll need to take apart the compressor section and see what is wrong. I have the same compressor.
 
Joined
May 14, 2007
Messages
516
Location
South Carolina
A 6hp motor will surely run on 240vac, probably a 30 amp circuit. 2 hp on 120vac usually needs a 20 amp circuit. Something in your information is not correct. If you are running a 240v motor with a 120v circuit, it certainly will trip the breaker. If someone put a 2hp motor on this compressor to run it on 120v, the pulleys are probably the wrong ratio for this hp. If the pipe on the outlet of the compressor is getting hot, it's compressing, but there may be an obstruction that won't let it get to the tank. Check the motor nameplate and lets start over.
 
Joined
May 26, 2003
Messages
9,832
Location
Central Coast, Calif.
his info is "correct" according to what the compressor says but not according to the laws of physics or truth in advertising. Several years ago companies selling consumer power tools were getting away with listing HP based on amperage at locked rotor. The laws have changed so you no longer see these kinds of claims. If its the same as mine it's a oiless so it doesn't have a seperate motor.
 
Joined
Aug 21, 2008
Messages
25,051
Location
ON, Canada eh?
 Originally Posted By: kkat
I recently purchased a new/used craftman air compressor from a yard sale, The guy I bought it from said he bought it 4 years ago and has never used it because it would keep blowing the circut breaker in the garage upon start up. and he just never got around to returning it or repairing it. I bought it and brought it home and sure enough it will blow the circut breaker in my garage circut box within 5 seconds, and the pipe gets very hot in that length of time. The compressor is an electric 120 volt, 15 amp with a 6 hp motor and a 33 gal tank, The circut I tried it on has a 20 amp circut breaker that I also I swapped out just in case of a bad one and still the same problem, also the circuit has nothing else drawing from it, It only has 1 plug on it that is above my work bench. Any Ideas as to what the problem could be?
My dad has this same one for smaller jobs and it turned out to be the Condenser was too small to start the motor and the motor would draw too much current and blow the circuit. He bought another condenser and wired it in, in parallel with the other condenser and it solved the problem. The condenser looks like a silver can with 2 wires coming out of it. Steve ;\)
 
Joined
Sep 26, 2002
Messages
4,679
Location
Central Arkansastan
I had the very same problem on mine several years ago. turned out, it was one of those copper staples they use on the shipping box. It somehow got caught inside the motor shorting it. removed it and runs fine.
 
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