21617

Power Down and Lock Out System

Switch off main power and engage lockout/tagout procedures. Ensure all capacitors are discharged before proceeding.

High voltage present - wait minimum 5 minutes after power down for capacitor discharge

Perform Insulation Resistance Test

Using a 500V megohmmeter, test insulation resistance between each motor cable phase (U, V, W) and ground. Minimum acceptable value is 1 MΩ per IEC standards.

Test at motor terminal box and drive output terminals separately to isolate cable vs motor issues

Inspect Cable Physical Condition

Examine entire cable run for mechanical damage, pinch points, sharp edges, or contamination. Pay special attention to cable entry points and bend radii.

Use thermal imaging to detect hot spots indicating partial insulation failure

Check Ground Fault Parameters

In STARTER or SINAMICS Commissioning Tool, verify P30135 (Ground fault monitoring) is set appropriately for your motor cable length and type.

For long motor cables >50m, consider adjusting P30135 to account for normal cable capacitance

Isolate Motor from Drive

Disconnect motor cables at drive output terminals (U1, V1, W1) to separate motor from drive system for independent testing.

Ensure proper lockout/tagout and verify zero energy state

Test Motor Winding Insulation

Perform insulation resistance test on motor windings using 500V megohmmeter. Test each phase to ground and phase-to-phase. Record values and compare to motor nameplate specifications.

Perform polarization index test (10min/1min reading ratio) for motors >1MW to assess insulation condition

Check Motor Terminal Box

Inspect motor terminal box for moisture, contamination, tracking marks, or damaged connections. Clean with appropriate solvents if contaminated.

Look for carbon tracking on insulators - appears as dark lines indicating flashover paths

Verify Drive Operation Without Motor

Temporarily connect drive to known good motor or load resistor to confirm drive ground fault detection is functioning correctly.

Use SINAMICS integrated commissioning functions to test drive without motor load

Access Drive Diagnostics

Connect to drive via STARTER software and check fault buffer (r0945) for additional fault codes. Review drive internal diagnostics and temperature monitoring values.

Check r0037 (fault code) history to identify any preceding alarms that may indicate component degradation

Inspect Drive Internal Components

With power removed and proper safety procedures, visually inspect IGBT modules, DC bus capacitors, and internal wiring for signs of failure, burning, or contamination.

Only qualified personnel should open drive enclosures - high voltage components present

Test Drive DC Bus Isolation

Measure insulation resistance between DC+ and ground, DC- and ground using appropriate test equipment. Values should exceed manufacturer specifications.

Use drive manufacturer's recommended test voltages to avoid damaging sensitive components

Check Environmental Conditions

Verify drive enclosure environmental conditions including temperature (r0037), humidity, and contamination levels. Check cooling system operation.

High humidity or condensation can cause internal ground faults - check HVAC system operation

Verify System Grounding Scheme

Check that system follows TN-S or TN-C-S grounding per IEC 60364. Verify single point grounding at main electrical panel and proper PE conductor sizing.

Use ground impedance tester to verify ground resistance <1Ω for industrial installations

Inspect Cable Shield Connections

Verify motor cable shields are properly connected at both drive and motor ends using 360° clamps. Check for shield continuity and proper termination.

Shield should be connected at drive end through EMC clamp, motor end through metal gland to motor frame

Check EMC Filter Installation

Verify EMC filter is properly installed with short connections to ground plane. Check filter ground connection integrity and mounting.

EMC filter ground connection should be <10cm to main ground point for effective operation

Review Ground Fault Parameter Settings

In STARTER, check P30135 (Ground fault monitoring) setting is appropriate for installation. Consider disabling temporarily for testing if installation is verified correct.

P30135=0 disables ground fault monitoring - use only for diagnostic purposes, not normal operation

Measure Incoming Power Quality

Use power quality analyzer to measure voltage balance, THD, and ground integrity on incoming supply (L1, L2, L3). Check for phase-to-ground voltage irregularities.

Voltage imbalance >2% can cause circulating currents that may trigger ground fault detection

Check Supply System Grounding

Verify incoming supply neutral and ground connections are proper and secure. Test for voltage between neutral and ground at supply point.

Voltage >2V between neutral and ground indicates supply grounding issues

Test with Different Power Source

If possible, temporarily connect drive to different power source or circuit to isolate supply-related issues from drive problems.

Use isolation transformer for testing to eliminate supply ground reference issues

Review Supply System Documentation

Check electrical drawings and verify supply system configuration matches drive requirements for grounding scheme and power quality.

Consult with facility electrical engineer to understand supply system grounding philosophy