IndustrialDriveDataDrive Board & Diagnostic Database
Diagnostic workflow

Safe First Inspection of an AC Drive Before Fault Tracing

Entry symptom: A drive has been removed from service or is being inspected before commissioning, wiring verification or deeper repair.

Safety controls before proceeding
  • Isolate incoming power and apply the correct lockout/tagout procedure.
  • Wait for the specified discharge interval and confirm the DC bus is discharged with appropriate test equipment.
  • Treat power, DC-link and motor-output terminals as hazardous until verified safe.

Investigation sequence

1

Identify the exact unit

Record brand, family, complete model code, rated voltage, frame/power rating and visible option markings before using any terminal or parameter record.

2

Separate input from output

Verify mains input terminals, DC-link/braking terminals and U/V/W motor output terminals before energization or cable correction.

3

Inspect installation conditions

Check cooling clearance, contamination, grounding, shielding and signs of condensation or conductive debris.

4

Select the next diagnostic record

Proceed from a verified symptom or fault code rather than replacing modules from visual suspicion alone.

Stop conditions

  • Unknown terminal identity
  • Visible DC-bus damage
  • Burnt power module or busbar
  • DC-bus voltage not discharged

Linked records

Circuit
Standard AC Drive Power Conversion Path

Most voltage-source AC drives follow a common conversion chain: mains input is rectified to a DC bus, filtered by the DC-link stage and switched through an inverter bridge to produce a controlled three-phase motor output.

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Evidence intake

Turn this record into a qualified service request

A repair decision is much more reliable when the request includes the exact identity of the drive, the first fault evidence and the machine condition when the symptom appeared.

  • Complete drive type code / MLFB or nameplate model
  • Fault code, fault value and first event before reset
  • When the event appears: power-up, enable, ramp, run, decel or stop
  • Motor/cable connected or isolated during the symptom
  • Visible board, option-card, module and connector identifiers
  • Previous repair history, replacement parts and repeat-failure pattern
Prepare request →