Power Unit Fault

What does F70 mean?

This is a general fault related to the drive's internal power unit. It indicates an internal hardware issue within the drive that cannot be resolved by simple troubleshooting.

• Internal failure of IGBTs (Insulated Gate Bipolar Transistors) within the drive's inverter section, often due to overcurrent, overvoltage, or thermal stress.
• Failure of the DC bus capacitors or the rectifier bridge, leading to unstable or incorrect DC link voltage.
• Damage to the gate driver circuit responsible for switching the IGBTs, resulting in incorrect switching or component damage.
• Component degradation or failure on the drive's power board due to age, environmental factors, or manufacturing defect.

Click steps to track your progress.

1. 1

   Isolate power to the drive. Visually inspect the drive's internal components for signs of burning, arcing, or bulging capacitors.

2. 2

   Disconnect all motor and input power wiring. Measure resistance between drive input terminals (L1, L2, L3) and between drive output terminals (T1, T2, T3) using a multimeter. Look for shorts.

3. 3

   Measure the resistance between drive input terminals and ground, and output terminals and ground. A low resistance indicates a ground fault within the drive.

4. 4

   Verify incoming supply voltage stability and phase balance using a true RMS multimeter or power quality analyzer to rule out external power issues.

5. 5

   If external checks are inconclusive and internal damage is suspected, the drive power unit has failed and the entire drive unit requires replacement.