231-C700

Check Main Power Supply

Verify all three phases at the main electrical panel using a multimeter. Check for proper voltage levels (typically 400-480VAC) and balanced phases within 2% of each other.

Use proper lockout/tagout procedures when working with high voltage

Inspect Power Contactors and Fuses

Check main contactors for proper operation and inspect all fuses in the power distribution. Look for blown fuses, burnt contacts, or loose connections.

Thermal imaging can quickly identify hot spots in power connections

Verify Power at ALM Module

Measure voltage directly at the ALM regenerative module input terminals to confirm power is reaching the unit with proper voltage levels and phase balance.

Check voltage under load conditions as well as no-load

Check ALM Module Status LEDs

Examine the status LEDs on the ALM regenerative module. Red or flashing LEDs indicate internal faults. Refer to the module's label for LED status meanings.

Document LED patterns before power cycling for diagnostic purposes

Verify DRIVE-CLiQ Communication

Check DRIVE-CLiQ cable connections to the ALM module. Ensure cables are properly seated and not damaged. Test communication through TNC diagnostics.

Swap DRIVE-CLiQ cables with known good ones to isolate cable issues

Monitor Internal Voltages

Use TNC diagnostic screens to monitor internal DC bus voltages and ALM module parameters. Look for voltage fluctuations or out-of-range values.

High DC bus voltages present - follow proper safety procedures

Install Power Quality Monitor

Connect a power quality analyzer to monitor voltage stability, harmonics, and transients over an extended period to identify intermittent power issues.

Monitor during typical machine operation cycles to capture load-related voltage drops

Check Voltage Regulation Settings

Verify that incoming power supply voltage regulation is within ±10% of nominal. Check transformer tap settings if applicable.

Coordinate with facility electrical personnel for utility power quality issues

Evaluate Power Factor Correction

Check power factor correction capacitors and ensure they are functioning properly. Poor power factor can cause voltage instability.

Capacitors may retain charge even when power is off

Perform Thermal Inspection

Use thermal imaging camera to identify hot spots in electrical connections throughout the power distribution system, focusing on terminal blocks and contactors.

Perform thermal inspection during normal operation with proper PPE

Torque Check All Connections

Systematically check and re-torque all power connections from main disconnect through ALM module input terminals according to manufacturer specifications.

Mark checked connections with paint pen to track progress

Clean and Treat Connections

Clean oxidized connections with appropriate contact cleaner and apply dielectric compound to prevent future corrosion.

Ensure power is off and locked out before cleaning connections

Verify System Grounding

Check continuity and resistance of all grounding connections. Ensure proper star-point grounding configuration and verify ground resistance is less than 1 ohm.

Use a dedicated ground resistance tester for accurate measurements

Check for Ground Loops

Identify and eliminate ground loops that can cause interference. Verify that control and power grounds are properly isolated where required.

Never disconnect safety grounds - consult electrical drawings

Install EMI Filtering

Add or verify proper EMI filtering on power lines if interference is suspected. Check for proper shielding of power cables.

Separate power and signal cables by minimum distances per Heidenhain installation guidelines