25105

Check AC Input Voltage

Navigate to Diagnostics > Drive > Power Supply and verify the AC input voltage readings against nameplate specifications (typically 380-480V for 3-phase systems).

Ensure proper PPE and lockout/tagout procedures before checking electrical connections.

Verify Power Supply Parameters

Check MD30100 (rated motor voltage) and MD30200 (minimum DC link voltage) in the drive parameter settings via HMI > Parameters > Machine Data.

Compare actual DC link voltage in r0026 with the threshold in MD30200 to confirm undervoltage condition.

Inspect Main Contactor and Fuses

Check the main power contactor operation and verify all input fuses are intact using the electrical cabinet diagnostics.

Power down the system completely before inspecting fuses or contactors.

Monitor DC Link Voltage Stability

Use HMI > Diagnostics > Drive > DC Link to observe r0026 (DC link voltage) during normal operation and look for voltage drops during acceleration or high load conditions.

Healthy DC link voltage should remain stable within ±5% during normal machining operations.

Check Capacitor Status Indicators

Navigate to Drive Diagnostics and check r0949 (drive unit status) for capacitor-related fault bits and review the drive's internal temperature readings.

DC link capacitors can retain dangerous voltage even when power is off - allow proper discharge time.

Perform Capacitor Load Test

Execute a controlled load test by running a typical machining cycle while monitoring r0026 for voltage sag patterns that indicate capacitor weakness.

Analyze Drive Status Word

Check r0052 (drive status word) and r0949 (drive unit status) for rectifier-related fault bits via HMI > Diagnostics > Drive Status.

Look specifically for bits indicating rectifier or power section faults in the status word interpretation.

Monitor Phase Current Balance

Observe r0027, r0028, r0029 (AC input currents L1, L2, L3) for significant imbalance that could indicate rectifier diode failure.

Rectifier failure can cause overcurrent conditions - monitor carefully and stop immediately if currents are unbalanced.

Check Drive Temperature Status

Review r0037 (drive temperature) and related thermal monitoring parameters to determine if overheating has damaged rectifier components.

Check Brake Resistor Status

Navigate to HMI > Parameters > Drive and verify MD30610 (brake resistor resistance) matches the installed resistor value and check r0036 for brake resistor temperature.

Brake resistor issues often manifest during rapid deceleration - monitor DC link voltage during these operations.

Verify Brake Chopper Operation

Check MD30600 (brake chopper enable) and monitor r0026 during deceleration cycles to ensure proper voltage regulation.

Faulty brake systems can cause dangerous overvoltage conditions during regeneration.

Test Regenerative Function

Perform controlled deceleration tests while monitoring the DC link voltage response and brake resistor activation through drive diagnostics.

Verify Voltage Threshold Settings

Check MD30200 (minimum DC link voltage) and ensure it matches the drive specifications - typically 85% of nominal DC voltage for the power supply rating.

Standard 400V systems should have MD30200 set to approximately 510V (85% of 600V DC nominal).

Review Power Supply Configuration

Verify MD30100 (rated motor voltage) and MD30110 (maximum motor voltage) are correctly set for your power supply configuration via HMI > Parameters > Drive.

Incorrect voltage parameters can cause drive instability or component damage.

Reset to Factory Defaults if Necessary

If parameter corruption is suspected, backup current settings and restore drive parameters to factory defaults, then reconfigure according to system specifications.