Crane will not hoist up or down. No fault on CCS, but drive shows “E OC” which means motor overcurrent.
Manually release brake, and fault changes to “E 68″ brake switch malfunction. This indicates that the drive is seeing an over current fault, and the brake is typically not the culprit. Verify brake is being released by drive, and verify brake disk adjustment. With brake manually released, the drum spins freely.
Found contactor K466M (motor heating) was stuck in the activated position. Could not release the contactor coil (contacts may be welded) Switched off Q407F, and crane hoists normally.
As drive would send voltage to motor to work, but motor was requiring more voltage than the drive was sending to rotate because it was heating the motor additionally. Drive would stop due to this ‘over current” sitauation.
