Elec guys, compressor motor ??

[Churchkey]

burned up the shop compressor motor after 21 years service.

5hp, 230v single phase, 22 amp, 1750 rpm. 1& 1/8 shaft.

Found a replacement, same as above, pricey B-tards anymore.

The compressor motor was wired through the pressure switch to a 50 amp double throw breaker.

Do I need some sort of heater or magnetic starter between the pressure switch & breaker?

I'm not getting a definative answer from the motor store I get the impression they are just trying to make another sale.

[alanh]

Is the PS wired in series with one of the motor leads AND IS IT double pole?

The circuit breaker could serve as motor running protection if the proper class device but most likely is only for short circuit protection imo.

ADDED: the PS is obviously wired up to the normally closed contact to unload the compressor at pressure!

If you want inexpensive nec code approved motor running protection you can use IEC components such as this:

http://www.amazon.com/Magnetic-Starter-Control-electric-compressor/dp/B004TGTU0W" target="_blank">http://www.amazon.com/Magnetic-Starter-Control-electric-compressor/dp/B004TGTU0W

http://www.amazon.com/Magnetic-Starter-Control-electric-compressor/dp/B004TGTU0W">http://www.amazon.com/Magnetic-Starter-Control-electric-compressor/dp/B004TGTU0W" /> http://www.amazon.com/Magnetic-Starter-Control-electric-compressor/dp/B004TGTU0W">http://www.amazon.com/Magnetic-Starter-Control-electric-compressor/dp/B004TGTU0W

or even a manual version w/o the 240v coil.

With the amazon part your PS would directly operate the new devices coil (240v) and leave the existing manual breaker as the means of disconnecting off line or alternately purchase a couple of timedelay fusetrons to wire in series with the existing components or motor overloads for running protection which is your goal.

[Churchkey]

Thanks Alan, have ordered the unit you suggested, local supplier wants twice the price.

W