Undervoltage
Vacon · NXP/C
What does 9 mean?
The DC-link voltage has fallen below the voltage limits defined in Table 37. This is most likely caused by a low or interrupted supply voltage. Subcodes in T.14 (S1, S2, S3) can indicate if the DC-link was too low during run, no data was received from the power unit, or undervoltage control supervision tripped. A persistent undervoltage condition can prevent the drive from operating or restarting.
Common Causes
- Input voltage below minimum threshold (e.g., P1-01 < P1-02).
- Loss of one or more input phases.
- Faulty main power supply unit.
- Brownout condition affecting the DC bus voltage.
- Incorrect voltage setting for the operating environment.
Repair Steps & Checklist
Click steps to track your progress.
- 1
If the fault occurred due to a temporary supply voltage break, reset the fault and restart the frequency converter.
- 2
Measure the incoming AC supply voltage at the frequency converter's input terminals and verify it is stable and within the specified operating range (e.g., 380-480VAC for a 400V class drive).
- 3
If the supply voltage is confirmed adequate, an internal failure has likely occurred. Contact your local distributor.