I've got this OLD dental compressor in the basement shop. I re plumbed it to a new tank when the original developed a leak. It seems the motor won't start without "jump' starting it by spinning the pulley on the compressor.
Can anyone guide me thru troubleshooting it? I can take some pics of it tonight.
The issue with just replacing the motor, is the fact the compressor is mounted above it, using some holes in the motor case.
Sounds like a specialty motor, made for the OEM. Might be a bit tough to find something like that for reasonable.
If it's not tripping the breaker when you try to start it, chances are nothing is grounded. Windings could be overheated and shorted but you can almost always smell the burn if you get a cover off. Looks and smells OK - pull out an ohm-meter. What resistance reading should you get? Impossible to say over the phone.
Less than infinity and more than zero is a good sign. If you get some ohm reading make sure you're getting power.
Centrifugal switches can be cleaned or replaced, and capacitors are mostly Chinese-made now so cheap as hell. In other words, even if they "test" good I'd replace them anyways.
Here's the on-line version of a motor troubleshooter I've used for years.
http://www.fasco.com/fasco/assets/File/F0007E_Fasco%20Facts.pdf