PowerFlex 525

Bus undervoltage is a supply problem or aging DC bus capacitors. Measure the AC input voltage under load first. A sagging supply needs upstream correction before the drive can run reliably.

Drive overheating is almost always a blocked heatsink or failed cooling fan. Clean the heatsink fins and verify the fan spins before any other troubleshooting.

Erratic speed is almost always noise on the analog speed reference or a loose encoder feedback cable. Measure the analog input signal at the drive terminals and check the reference source before adjusting control parameters.

F004 means the DC bus dropped below the trip threshold. Verify line voltage, P031 (Motor NP Volts), and the input fuses; then power-cycle.

A ground fault means one of the motor cable conductors or motor winding has broken down to ground. Megger the cable and motor separately to isolate the fault location.

Overcurrent faults most often come from an accel time that's too short for the load, a motor wiring fault, or a jammed load. Lengthen the accel ramp first and check motor lead insulation.

Overvoltage faults during deceleration mean the bus cannot absorb regenerative energy fast enough. Lengthen the decel ramp first. If the load is high-inertia, add a dynamic braking resistor.