DC link voltage high

What does 5 mean?

The DC-link voltage is higher than the drive's high-voltage warning limit, which depends on the drive voltage rating. The unit remains active at this warning state, but continued high voltage could lead to an overvoltage trip.

• High incoming mains voltage exceeding the drive's nominal operating range (e.g., 480V instead of 400V).
• Regenerative energy from the motor during fast deceleration or overhauling load (e.g., hoist lowering, fan windmilling).
• Faulty brake resistor (e.g., open circuit in element R301) or brake chopper circuit (e.g., gate driver failure) preventing energy dissipation.
• Parameter P1-54 (Motor Rated Voltage) set too low relative to the actual motor and supply voltage, causing incorrect DC link monitoring.
• Drive's internal DC-link voltage sensing circuit malfunction or calibration drift.

Click steps to track your progress.

1. 1

   Measure the incoming AC line-to-line voltage at the drive's input terminals (e.g., L1-L2, L2-L3, L3-L1) and confirm it is within specified limits.

2. 2

   Monitor the DC-link voltage (e.g., via LCP or terminals +DC, -DC) during deceleration ramps or hoist lowering operations.

3. 3

   Measure the resistance of the external brake resistor (e.g., across terminals 81 and 82) and compare it to the specified value (e.g., 100 Ohms).

4. 4

   Verify the operation of the brake chopper IGBT by checking gate drive signals or current flow through the brake resistor during regeneration.

5. 5

   Increase the deceleration ramp time (e.g., P3-42 Decel Ramp Time) to reduce the rate of regenerative energy fed back to the DC link.