Quincy QGS 10 Rotary screw would not cut in, now it won't turn on.

by Ben
(Perkins, MI USA)

We have a 3 phase Quincy QGS 10 Rotary screw compressor. Compressor is just over a year old. We had a problem with it not cutting in, so we shut it down to inspect the pressure switch, connections, etc.


Now it will not turn on. The pressure switch (condor mdr1) only has two wires going to it from the main control box.

I can manually depress the main motor contactor and it seems as though it is stuck in an unloaded state (motor/screw turning but not compressing air). The on switch will not activate the contactor to start the motor.

Any ideas to point us in the right direction would be helpful.

Thanks!

Comments for Quincy QGS 10 Rotary screw would not cut in, now it won't turn on.

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Feb 16, 2017
would not cut in
by: Doug in s.d.ca.

Yes, and that also explains the original.

Thanks for the update.

Feb 15, 2017
Compressor Fixed!
by: Anonymous

It turns out that the pressure switch simply had a loose wire. I believe the loose wire caused the main contactor/OL relay to arc, damaging the connections. I was able to clean the contacts good enough to run until the replacements get here.

Feb 13, 2017
now it won't turn on
by: Doug in s.d.ca.

Any chance when you were checking, you reversed the motor connections?

Don't know it can sense that, but it might.

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