KRC0070

Common Causes

• Main power supply disconnected or power loss to the robot controller
• Faulty or worn drives contactor that has opened unexpectedly
• Emergency stop (E-stop) activated, triggering contactor shutdown
• Intermediate circuit capacitor bank failure or insufficient charge voltage
• Control voltage dropout or loss of contactor control signal

Troubleshooting Steps

1. 1Verify that main power supply to the KRC controller is present and within specification (typically 3-phase 400V ±10%)
2. 2Check the physical condition of the drives contactor for signs of wear, arcing, or mechanical failure
3. 3Inspect all power cables and connections between the main power input and power module for loose or corroded terminals
4. 4Verify that the emergency stop circuit is not activated; reset E-stop button if necessary and attempt robot restart
5. 5Measure intermediate circuit voltage with a multimeter; it should charge to approximately 560V DC within 30 seconds of power-on
6. 6If voltage does not charge properly, inspect the power module capacitor bank and control relay circuits, or contact KUKA service for power module replacement