York comprerssor

[COBRAKAI]

Hello techs!!

I recently received a call about a 3ph york compressor going out on thermal overload. One of the phases is pulling 60amps and other 2 are ok. The eng has done a phase rotation check and also mega the circuits and all is ok. Think the comp is on a chiller not sure though. sorry about lack of details Iv never heard of this fault and thought Id put it out there.

[Brian_UK]

Check and recheck all of the wiring, contactors etc.

[Magoo]

Check the supply side of things, the MCB, contactor etc., a faulty overload or contactor leg will give similar high current on one phase, loose terminals etc, etc. as Brian suggested double check everything up stream of compressor windings. The last straw is a mildly cooked winding, it will not show up with a multimeter but a high voltage meggar should nail it. Good luck.
magoo

[Tesla]

Hi COB
Just a point to ensure you check the comp with a Mega and remove (if any) copper connection plates on the motor terminals. Also voltage or current imbalances. You could also Mega across each of the contactors. On one chiller we found a hot joint with a thermal scanner on a crimped cable end (bad crimp). Please let us know how you go and what you find on this one.

[yoleysi]

how to check an AA phase compressors