I am trying to help a customer out with this problem. There is an AC drive running a motor on a paper mill. Not 100% of the time, but frequently, during either the accel or decel, at a specific speed, the current will spike up and trip the drive. There is a 20s accel and decel time. When speed hits around 55% rated motor speed, the current will start climbing until get overcurrent fault on drive. Or, may not do this on accel, but then stop drive, and when speed drops to around 55%, get current spike and bus voltage spike, and get fault also. Can a bad motor do this?
