443

Immediately inspect the axis mechanically: check for collision damage, chips/debris in ballscrew/ways, bent components, or abnormal resistance when manually rotating the motor (power OFF, release brakes). Verify coupling condition and tightness.

Lock out machine power and follow LOTO procedures before manual inspection

Check DIAGNOSIS screen > Servo monitor (path varies: SYSTEM > DIAGNOSIS > SERVO or PMC > DIAGNOSIS). Monitor parameters 300-303 (current feedback) and 200-203 (positional deviation) during slow jog. Excessive current spikes or high deviation indicate mechanical resistance.

Verify counterbalance operation if applicable (Z-axis). Check hydraulic/pneumatic pressure gauges and balance valve function. Imbalanced Z-axis creates constant high current load.

Lubricate ballscrews andways per OEM specifications. Check gib adjustment - over-tightened gibs cause excessive friction and current draw. Re-check axis movement and alarm condition after mechanical corrections.

Check servo amplifier LED codes on the affected axis module. Refer to amplifier-specific LED diagnostic chart (αi series: solid red = alarm state; βi series: 4-digit LED code). Document any displayed codes for correlation with alarm 443.

Perform motor insulation resistance (megger) test: disconnect motor power cables at amplifier, test each phase (U, V, W) to motor ground. Should read >10MΩ minimum. Values <1MΩ indicate insulation breakdown requiring motor replacement.

Disconnect all motor and encoder cables before insulation testing to prevent amplifier damage

Inspect encoder cable (α/β cable) for damage, pinching, or contamination at connectors. Check encoder feedback on DIAGNOSIS screen parameters 400-403 (position data) during manual rotation - erratic readings indicate encoder/cable issues causing improper commutation and excess current.

If motor/encoder test OK, suspect amplifier power module failure. Swap amplifier with known-good axis (same model/rating) or install spare. Clear alarms and test. If alarm follows amplifier, replace amplifier. If alarm stays with axis, motor is likely faulty.

Ensure amplifier model and parameters match before swapping; verify DIP switch settings on older amplifiers

Verify Parameter 2020-2027 (servo motor type code) matches the installed motor model. Cross-reference with motor nameplate data. Mismatched motor codes cause incorrect current calculations and limits.

Incorrect motor parameters can cause immediate damage; verify before enabling servo

Check Parameter 2048-2055 (maximum current limit) for the affected axis. Typical values 150-300% of rated motor current. Compare with motor nameplate rated current. Abnormally low settings trigger false excess current alarms.

Review servo gain parameters: 1825-1832 (position gain), 2018-2019 (velocity loop gain). Excessively high gains cause oscillation and current spikes. If recently changed, restore factory defaults from servo motor parameter manual or OEM backup.

If parameters were recently modified or amplifier/motor replaced, perform automatic servo tuning: Set Parameter 2681 bit 0=1 (auto-tuning mode), execute G00 moves across full axis travel, then set bit back to 0. Verify alarm clears after tuning completion.

Ensure axis mechanics are sound before auto-tuning; tuning cannot compensate for mechanical issues