Originally Posted by drewhart
i have a porter cable pancake air compressor with an emglo oil engine. i have to turn it on and then off right away about thirty times before it will run. it just hums otherwise. if i turn it on and leave it on too early the compressors internal circuit breaker or the breaker in the box will trip. i have been told it coulde be a weak compacitor or a bad start valve. what do you think i should do? are these hard things to replace?
actualy it may not be a porter cable one. its red and the pancake is on its side. there is a square cage around it with a handle in the middle. i bought it from a guy and i forgot what kind it is.
Some motors have two windings. A start winding and a run winding!
A centrifugal switch transfers the power from the start winding to the run winding.
These centrifugal switches are prone to 'arc' damage and carbon buildup.
When the motor is turned off, the 'break' contacts must close to allow current to flow through the start winding.
If the 'make' contact is still closed to the 'run' winding it will cause the over current protection to function.
Repair of these can be tricky, as the contact 'gap' is set using a 'feeler' guage.
If you have good mechanical skills, and the necessary tools, you may be able to repair it yourself!