231-8B60

Power Down and Isolate System

Switch off main power and lock out. Navigate to MOD function and ensure all axes are in safe position before cable inspection.

Never disconnect motor cables under power - risk of arc flash and component damage

Inspect Motor Cable Integrity

Visually inspect entire motor cable run for pinch points, cuts, or damage. Check cable entry points at motor and amplifier for proper strain relief and sealing.

Pay special attention to areas where cables pass through cable chains or sharp edges

Measure Cable Insulation Resistance

Using megohmmeter, test insulation between all motor phases (U-V, V-W, W-U) and each phase to ground. Should read >10MΩ minimum.

Test at motor connector with cable disconnected from amplifier to isolate cable faults

Check Connector Pin Integrity

Inspect motor and amplifier connectors for bent pins, corrosion, or foreign debris. Verify proper mating and torque specifications per Heidenhain documentation.

Disconnect Motor from Amplifier

With power off, disconnect motor power connector at amplifier end. Access through Service menu to review axis parameters and note motor type designation.

Tag and photograph connector orientation before removal

Test Motor Winding Resistance

Measure DC resistance between motor phases U-V, V-W, W-U using precision multimeter. Values should be balanced within 5% and match motor nameplate specifications.

Compare readings with identical motors on other axes - significant deviation indicates winding problems

Perform Insulation Resistance Test

Test insulation resistance from each winding to motor frame/ground using 500V megohmmeter. Minimum acceptable reading is 10MΩ for most servo motors.

Check Motor Temperature History

Access Machine Parameters MP7xx series to review motor temperature monitoring data and verify thermal protection settings are appropriate for motor specifications.

Access Servo Diagnostics

Navigate to Service menu → Servo Diagnosis → select affected axis. Review current monitoring values and IGBT status indicators for anomalies.

Compare diagnostic values between axes to identify abnormal readings

Perform Amplifier Self-Test

With motor disconnected, initiate servo amplifier internal diagnostics through Service menu. Monitor for IGBT gate drive errors or power stage faults.

Check DC Bus Voltage Stability

Monitor DC bus voltage in servo diagnostics during normal operation. Voltage should remain stable within ±5% of nominal value (typically 540-560VDC).

High voltage present - use appropriate PPE and follow lockout procedures

Review Amplifier Temperature Data

Check servo amplifier temperature monitoring through diagnostics menu. Verify cooling fans operational and heat sink temperatures within normal range.

Check Axis Movement Manually

With servo drives disabled via Emergency Stop, manually move affected axis through full travel range. Feel for binding, unusual resistance, or mechanical interference.

Ensure all safety systems are active and machine is properly locked out

Review Following Error History

Access Service menu → Position Monitoring to review following error trends and maximum values recorded before alarm occurrence. High following errors indicate mechanical resistance.

Inspect Mechanical Components

Check ballscrews, linear guides, and coupling components for proper lubrication, wear, or damage. Verify all mechanical fasteners are properly torqued.

Verify Load Parameters

Review Machine Parameters MP1xxx series for axis load and inertia settings. Ensure values match actual mechanical configuration and haven't been inadvertently changed.

Backup Current Parameters

Navigate to File Management and create backup of current machine parameters before making any changes. Store on external media for recovery if needed.

Verify Motor Configuration Parameters

Check Machine Parameters MP7xx series for correct motor type, rated current, and electrical specifications. Compare against motor nameplate data.

Motor parameters must exactly match physical motor - even small discrepancies can cause overcurrent conditions

Review Current Limit Settings

Examine MP7xx current limit parameters ensuring they're set appropriately for motor specifications and application requirements. Verify both continuous and peak current limits.

Restore Default Servo Parameters

If parameters appear incorrect, restore factory defaults for the specific motor/amplifier combination and perform servo optimization procedure per Heidenhain documentation.