200hp motor burns contactor
200hp motor burns contactor
(OP)
200 hp 3 phase 2speed motor burning up high speed size 5 contactor. Low speed draws 64 amps/high speed amps 223 when running correctly. Motor has been rebuilt. Time delay between low speed and high speed. aprox 30 sec. shows aprox 3-4% voltage drop at MCC contactor can, motor is another 85 ft away. Cutler-hammer contactor vibrates when pulled in. (more than normal) Burns (a phase) when going to high speed, contact point melted. Replaced contactor three times, with new size 5 cutler-hammer style.
Same problem occurs about every 5 to 6 weeks. Where else should I be looking?
Same problem occurs about every 5 to 6 weeks. Where else should I be looking?






RE: 200hp motor burns contactor
Perhaps the control voltage dipping from something. As frequent as it is occurring you should immediately get a recorder going on the control voltage across the contactor coil. You will likely see something immediately if not sooner.
Keith Cress
kcress - http://www.flaminsystems.com
RE: 200hp motor burns contactor
If the contactor is at the MCC and not near the motor, you can rule-out voltage dip, IMO.
RE: 200hp motor burns contactor
Bill
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Jimmy Carter