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KUKA Robot Controller
Power Supply · Basic
KUKA Robot KRC0211 - ACKN K1 CONTACT FAIL TO OPEN <KPS number>
The K1 safety contactor in the specified KPS (KUKA Power Supply) unit has failed to open during a commanded shutdown or safety stop sequence, indicating the contacts are welded or permanently stuck in the closed position. This is a critical safety failure that prevents the proper de-energization of the robot drive system and violates safety interlock requirements. The robot will not resume operation until this condition is resolved.
KRC0211
KUKA Robot KRC0211 - ACKN K1 CONTACT FAIL TO OPEN <KPS number>
ACKN K1 CONTACT FAIL TO OPEN <KPS number>
The K1 safety contactor in the specified KPS (KUKA Power Supply) unit has failed to open during a commanded shutdown or safety stop sequence, indicating the contacts are welded or permanently stuck in the closed position. This is a critical safety failure that prevents the proper de-energization of the robot drive system and violates safety interlock requirements. The robot will not resume operation until this condition is resolved.
Common Causes
- Welded or fused K1 contactor contacts due to electrical arcing or high-current transients
- Mechanical failure or jamming of the contactor plunger preventing proper opening
- Contamination or corrosion on the K1 contactor contacts reducing contact separation
- Inadequate maintenance or inspection intervals allowing contact degradation
- Repeated safety stops or emergency stops causing accelerated contactor wear
Troubleshooting Steps
- 1Immediately stop all robot operations and place the system in a safe state; verify no personnel are in the work envelope
- 2Power down the KUKA KRC controller and confirm all drive power is discharged using proper lockout/tagout procedures
- 3Visually inspect the K1 contactor in the specified KPS unit for signs of arcing, contact fusion, mechanical damage, or debris
- 4Attempt manual actuation of the K1 contactor plunger to verify mechanical function; do not force if resistance is excessive
- 5If the contactor is welded or mechanically stuck, replace the K1 contactor assembly with an OEM KUKA replacement part rated for the same specifications
- 6After replacement, perform a full safety system test including multiple emergency stop cycles and verify K1 contact opening with a multimeter before returning the robot to production
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