Hey all,
ive got an Mtz 81 maneurop compressor that's opening circuit just on one phase while running. The amps are initially fine (10.2 amps) on all three phases .after a minute or so the one phase stops drawing current, the other 2 climb to 18 amps. This could seem like I've lost a phase but I'm reading line voltage across all terminals at the compressor. I turn off the compressor and meter out the windings and only get continuity through 2windings and nothing through the one.Seconds later the winding returns and on starting the compressor the amps are fine for a bit again.

Firstly does the maneurop compressor internal overload open all windings when it trips? Because this compressor is opening one winding only.
secondly the compressor is showing no indications of high amps for the overload to react to? The compressor is also cool to the touch so I don't think it's tripping from heat?
while running the pressures look ok . could this be a faulty internal overload or am I missing something?