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Power Down and Isolate Drive

Switch off main power and ensure SIMODRIVE LED shows no power. Remove motor cable from power module X4 connector.

Always follow LOTO procedures before disconnecting power connections

Measure Cable Insulation

Use megohmmeter to test insulation between U-V, V-W, W-U phases at motor cable. Should read >10MΩ minimum.

Test both at drive end and motor end to isolate fault location

Inspect Cable Routing

Check motor cable for pinch points, sharp edges, or damage along cable track. Verify minimum bend radius per Siemens specifications.

Look for oil contamination which can cause insulation breakdown

Replace or Reroute Cable

If insulation fault found, replace motor cable with Siemens approved type. Ensure proper separation from signal cables.

Use shielded motor cable and connect shield to both drive and motor PE terminals

Disconnect Motor from Drive

Remove motor cable from SIMODRIVE X4 connector. Clear alarm using HMI Diagnostics > Alarms > Delete or NC Reset.

Ensure motor is mechanically secured before electrical disconnection

Test Motor Winding Resistance

Measure DC resistance between motor terminals U-V, V-W, W-U using precision ohmmeter. Values should be balanced within 2%.

Compare readings to motor nameplate data or previous measurements

Perform Insulation Test

Test insulation resistance from each phase to motor frame/PE using 500V megohmmeter. Minimum 1MΩ required.

Test at motor operating temperature if possible - hot windings show lower insulation

Check Motor Parameters

In SINUMERIK HMI, verify motor data in MD36300-36310 matches actual motor nameplate specifications.

Incorrect motor parameters can cause overcurrent conditions that appear as short circuits

Check SIMODRIVE LED Status

Observe SIMODRIVE status LEDs. Red LED indicates internal fault. Check parameter P30902 for detailed fault buffer.

LED patterns are documented in SIMODRIVE manual - steady vs. flashing indicates different faults

Perform Drive Self-Test

Access HMI Service > Drive Diagnosis > Self Test. Run internal diagnostics to verify power module integrity.

Self-test must be performed with motor disconnected

Check DC Bus Voltage

Verify DC bus voltage in parameter P30001 is within specification (typically 540-720V for 400V systems).

Low DC bus can cause IGBT stress leading to failure

Replace Power Module

If internal fault confirmed, replace SIMODRIVE power module. Transfer parameters using CF card or SINUMERIK backup.

Only qualified personnel should replace power modules - high voltage present

Check Ground Fault Parameters

Verify parameter P30240 (ground fault monitoring) is properly configured. Check P30241 for ground fault threshold settings.

Ground fault sensitivity may need adjustment in high EMI environments

Test Phase-to-Ground Insulation

Measure insulation resistance from each motor phase (U,V,W) to motor frame and machine ground using 500V megohmmeter.

Perform test with motor at operating temperature - insulation resistance decreases when hot

Inspect Motor and Cable Environment

Check for coolant leaks, condensation, or contamination on motor housing and cable connections.

Clean motor with appropriate solvents only - some cleaners attack insulation

Verify Grounding System

Ensure proper PE connection from motor through cable shield to drive ground terminal. Check continuity and tightness.

Use star-point grounding configuration to minimize ground loops

Verify Motor Data Parameters

Check MD36300 (rated motor voltage), MD36310 (rated motor current), MD36320 (rated motor speed) match motor nameplate exactly.

Use SINUMERIK motor database when available for automatic parameter setting

Check Current Monitoring Settings

Verify P30200 (maximum current) and P30201 (current monitoring time) are appropriate for motor size and application.

Set maximum current to 1.5x motor rated current for normal applications

Review Commutation Settings

For synchronous motors, verify encoder alignment in MD36400 and commutation offset in MD36410 are correct.

Incorrect commutation can cause high currents that trigger short circuit protection

Perform Motor Identification

Run automatic motor identification routine via HMI Service > Drive > Motor ID to automatically set optimal parameters.

Motor ID should be performed at operating temperature for best results