Air Compressor Problems

[Toyota FJ40]

I have a dayton 2 cyl. air compressor that is quite old, but the pump has been recently been rebuilt, and has excellent compression. It has a hard time starting, everything spins freely, but the motor just doesn't want to spin, even without the belt attatched. If it starts it works fine and doesn't have any excessive noise. Does anybody have any ideas on what this could be and how it could be fixed?

[guidolyons]

How old is the motor? Most compressor motors are capacitor start, becasue of the high initial torque required to turn the compressor. It may need a rebuild, also or the capacitor may be going bad, so that's why it only works sometimes. Check the yellow pages for electric motor repair it should be easily repaired or try a new/rebuilt motor.

[MarkW]

I agree with Guido above (hey, NEVER disagree with a guy names Guido!)

There are 2 circuits to an electric compressor motor, a start circuit and a run circuit. Your start circuit is bad obviously. If this has a centrifugally operated switch in it, it may be stuck. Unplug it and take the covers off. If there is a switch you can get at click it back and forth a few times, and maybe polish the contactors if you can figure it out. Otherwise it is most likely how Guido says, and the capacitor is bad. Take the Cap out and go to an electric motor shop for a replacement, or look it up online.

[FSR BIKER]

Not to hiJack the thread but....On mine(5hp) the motor starts and runs for about 15 seconds and then pops the breaker...as well as slightly smokes. The compressor hasn't been run in a few years but I don't think that should have caused the motor to go. Any ideas or good sources for a 5hp motor?

[Toyota FJ40]

Thanks, I'll give that a try. I was kindof thinking that the capacitor was bad, but it is good to have a few extra things to try, I will tear into it asap and check out that little switch, if thats not bad I will replace the capacitor.