231-8BC0

Verify Motor Parameters

Access MOD function, navigate to CfgAxisList, check MP720 (motor type), MP721 (rated current), MP722 (rated voltage) match actual motor nameplate data.

Compare MP721 rated current with actual motor nameplate - mismatches here are the most common cause of this alarm.

Check Power Module Rating

Verify power module part number matches motor requirements. Check MP740 (max motor current) is properly configured for the installed power module.

Never exceed power module current rating - this can cause permanent damage to drive electronics.

Validate Current Monitoring Settings

Check MP741 (current monitoring threshold) and MP742 (current monitoring time). Reset to default values if uncertain about previous modifications.

Power Down and Isolate Motor

Turn off main power, disconnect motor cable at both drive and motor ends. Use lockout/tagout procedures.

Always verify zero energy state before disconnecting motor cables - high voltage may be present.

Perform Cable Insulation Test

Using megohmmeter, test insulation resistance between each motor phase (U,V,W) and between phases to ground. Minimum 1 megohm required.

Flex the cable during testing - intermittent faults often show up with cable movement.

Check Cable Continuity and Routing

Verify continuity of each conductor, inspect cable routing for pinch points, sharp edges, or contact with hot surfaces that could damage insulation.

Access Spindle Parameters

Navigate to MOD function, CfgSpindleList, locate MP3110 (acceleration time) and MP3111 (deceleration time) for the affected spindle axis.

Start with conservative ramp times (2-3 seconds) and gradually decrease while monitoring current draw.

Adjust Ramp Gradients

Increase MP3110 and MP3111 values to reduce acceleration rates. Check MP3112 (S-curve smoothing) is enabled to reduce current spikes.

Too aggressive ramp rates can damage both motor and spindle bearings over time.

Test Spindle Operation

Run spindle through full speed range using MDI mode with M3 S1000, gradually increasing speed while monitoring for alarm recurrence.

Disconnect and Test Motor Windings

With motor disconnected, measure winding resistance between U-V, V-W, W-U phases. Values should be equal within 5% and match motor specifications.

Unbalanced winding resistance often indicates turn-to-turn shorts in motor windings.

Check Motor Mechanical Condition

Manually rotate motor shaft to check for binding, rough bearings, or mechanical obstructions. Listen for unusual noises or grinding.

Remove all power and ensure motor is mechanically isolated before manual rotation.

Inspect for Contamination

Check motor housing for signs of moisture ingress, oil contamination, or debris accumulation. Verify IP rating matches environmental conditions.