compressor unloader

by Jeff S
(Illinois)

I have a homemade unit that won't allow the motor(3/4h.p.) to turn over the compressor when the receiver is pressurized which obviously blows fuses in my garage if I leave it energized over a few seconds. I have a 1/4 in. copper line piped from compressor head directly to the check valve, which by the way is working properly. Will a bigger motor solve my problem or do I need an unloading valve between compressor and check? I don't have a pressure switch on this unit to automate it somewhat, but I can't until this first problem is remedied. Any info you can give would be great!

---

Bill answers...

Hey Jeff:

It's the absence of the unloader valve that's an integral part of a standard pressure switch that's likely your problem.

Electric motors draw higher amperage when they start. An electric motor that's trying to start against a higher load (eg: moving a cylinder piston against a charge of compressed air)will draw more amperage than normal, and this higher draw is likely what's blowing your fuses.

If you've got the amperage in your lines to feed a higher HP motor, sure, that would help.

Be easier to integrate a pressure switch though.

Not having a pressure switch seems a bit puzzling to me. What turns your compressor off when it reaches your high pressure set point?

Cheers,

Bill