D101 Brake Slip Fault in ABB ACS880 Drive

D101 Brake Slip in the ABB ACS880 Drive indicates that the mechanical brake slipped during the Torque Proving sequence. During Torque Proving, the drive applies torque while the mechanical brake remains engaged to verify that the brake can safely hold the load. If the drive detects unexpected motor movement or brake slippage while the brake should remain closed, it generates Fault D101 to prevent unsafe operation.

This fault generally indicates a problem with the mechanical brake, brake holding force, brake adjustment, or the mechanical load, rather than a fault in the drive itself.

Possible Causes

• Mechanical brake slipped during Torque Proving.
• Brake holding force is insufficient.
• Worn brake friction lining.
• Brake pads or shoes worn excessively.
• Brake improperly adjusted.
• Brake spring weakened or damaged.
• Brake not fully closing.
• Brake coil not completely de-energized.
• Mechanical brake linkage fault.
• Excessive load exceeding brake holding capacity.
• Oil, grease, or contamination on brake surfaces.
• Incorrect brake installation.
• Mechanical wear of the brake assembly.
• Incorrect Torque Proving configuration.
• Brake acknowledgement signal does not match the actual brake status.

Solutions

• Cycle power to the drive and check whether the fault clears.
• Inspect the mechanical brake for proper operation.
• Verify that the brake remains fully closed during Torque Proving.
• Check whether the brake slips while in the closed state.
• Inspect the brake friction surfaces for wear or contamination.
• Verify the brake adjustment according to the equipment manufacturer's specifications.
• Inspect the brake spring and mechanical linkage.
• Ensure the brake coil is fully de-energized when the brake should be closed.
• Check the brake holding capacity against the application load.
• Remove oil, grease, or contaminants from brake surfaces.
• Verify brake acknowledgement signals if used.
• Replace worn brake pads, linings, or other defective brake components.
• Repeat the Torque Proving procedure after correcting the brake issue.
• Contact ABB technical support if the fault persists after brake inspection.

Additional Information

The ABB ACS880 performs Torque Proving in applications where safe load holding is critical, such as:

• Cranes
• Hoists
• Elevators
• Winches
• Lifting equipment

During this procedure, the drive develops motor torque while the mechanical brake remains engaged. The objective is to verify that the brake can safely hold the load before normal operation begins.

If the drive detects any unexpected shaft movement while the brake should remain fully applied, it generates Fault D101, indicating that the brake has slipped.

Common reasons include:

• Worn brake friction material.
• Incorrect brake adjustment.
• Reduced spring force.
• Brake contamination.
• Excessive mechanical load.

Unlike D100 – Torque Prove, where the motor cannot develop sufficient torque, D101 indicates that the motor develops torque but the mechanical brake fails to hold the load securely.

Common Symptoms

• Drive trips with Fault D101.
• Torque Proving sequence fails.
• Motor shaft moves while the brake should be engaged.
• Load drifts during startup.
• Mechanical brake appears unable to hold the load.
• Fault occurs only during startup.
• Brake releases unexpectedly.
• Drive cannot complete the startup sequence.
• Hoist or lifting application fails safety verification.
• Fault remains until the brake problem is corrected.

Recommended Troubleshooting Sequence

1. Cycle power to the drive.
2. Inspect the mechanical brake.
3. Verify the brake remains fully closed during Torque Proving.
4. Check for brake slippage while engaged.
5. Inspect brake friction surfaces.
6. Verify brake adjustment.
7. Inspect the brake spring and linkage.
8. Check brake coil operation.
9. Verify brake acknowledgement signals if used.
10. Inspect the mechanical load.
11. Clean contaminated brake components.
12. Replace worn brake parts if necessary.
13. Repeat the Torque Proving procedure.
14. Verify successful startup.
15. Contact ABB technical support if the fault persists.

Brake Slip Check Table

Check Point	Action
Power cycle	Restart the drive
Mechanical brake	Inspect for proper operation
Brake holding	Verify brake remains fully closed
Brake slip	Check for movement while brake is engaged
Brake friction surfaces	Inspect for wear or contamination
Brake adjustment	Verify correct adjustment
Brake spring	Inspect for weakening or damage
Brake linkage	Check for mechanical faults
Brake coil	Verify complete de-energization
Brake acknowledgement	Verify feedback matches actual brake status
Mechanical load	Confirm brake holding capacity is sufficient
Torque Proving	Repeat after repairs
ABB technical support	Contact if the fault remains after inspection

Preventive Maintenance Tips

• Inspect the mechanical brake regularly for wear and proper operation.
• Replace worn brake pads, shoes, or friction linings before holding capacity is reduced.
• Keep brake friction surfaces clean and free from oil, grease, or dust.
• Periodically verify brake adjustment according to the equipment manufacturer's recommendations.
• Inspect brake springs and mechanical linkages for wear or fatigue.
• Test brake holding performance during scheduled maintenance.
• Verify brake acknowledgement signals are operating correctly.
• Ensure the brake is properly sized for the application load.
• Perform Torque Proving after brake maintenance or replacement.
• Record recurring brake slip faults to assist long-term diagnostics.

Proper inspection of the mechanical brake, verification that the brake remains fully engaged during Torque Proving, routine maintenance of brake friction components, springs, and linkages, and confirmation that the brake holding capacity matches the application load will help prevent recurring D101 Brake Slip faults in ABB ACS880 drives, ensuring safe load holding, successful Torque Proving, reliable startup, and dependable long-term operation of the drive system.