Power unit: DC link overvoltage

What does A30502 mean?

The power unit has detected an overvoltage condition in the DC link during a pulse inhibit state, likely due to an excessively high device supply voltage or an incorrectly dimensioned line reactor. Persistent DC link overvoltage can critically stress the power electronics, significantly reducing the drive's lifespan. If left unresolved, it can lead to catastrophic hardware failure.

• Regenerative energy from the motor (e.g., during deceleration) is flowing back into the DC link, exceeding the allowed voltage threshold (P2172).
• Incorrectly sized or non-existent braking resistor or a malfunctioning braking chopper circuit.
• High line voltage (mains supply voltage) causing the DC link to rise above its nominal level, even during pulse inhibit.
• Faulty DC link voltage sensing circuit within the power unit, providing an erroneous high reading.
• Line reactor (if present) is incorrectly dimensioned or faulty, contributing to voltage spikes.

Click steps to track your progress.

1. 1

   Measure the DC link voltage (r0026) while the drive is decelerating or stopping and compare it to the overvoltage threshold (P2172).

2. 2

   Verify the presence and correct resistance value of the braking resistor (if applicable) and check its connections (e.g., X10 terminals 1/2).

3. 3

   Increase the deceleration ramp time in parameter P1121 to reduce regenerative energy flow during deceleration.

4. 4

   Check the incoming line voltage (r0025) and ensure it is within the drive's specified operating range.

5. 5

   Inspect the braking chopper circuit for proper function, specifically the switching components.