Operator complains crane will not start and the display shows Three phase power supply missing. Check for incoming power and all 3 phases. If power is correct on each of the three legs (277 VAC), check contactor K102M. A1 terminal should be receiving 277VAC on the A1 terminal. If that is correct, coil in contactor may be bad. Remove wire from terminal 22, hold in contactor and start the crane. If crane starts and runs, the contactor coil has failed.
To bypass contactor K102M wire the incoming and outgoing 3 phase wires together and disconnect terminal 22 on K102M. This will allow the crane to function until the K102M can be replaced.
Potain part # for K102M = 84034156
