Danfoss · VLT 2800 Variable Speed Drive
The DC bus voltage (VDC) has exceeded the 'Voltage warning high' limit. The motor continues to operate, but if the VDC remains high for 5-10 seconds, the inverter will trip with an Alarm 7 (Overvoltage). This can be caused by an excessively high supply voltage or fast motor deceleration with insufficient braking.
Click steps to track your progress.
1. Measure the incoming AC line voltage (phase-to-phase) at terminals R, S, T and compare to the drive's rated input voltage; report any sustained overvoltage to facility maintenance.
2. Verify drive deceleration ramps (P2-01, P2-02) are set appropriately for the load inertia, consider increasing ramp times to reduce regenerative energy.
3. If an external braking resistor is installed, measure its resistance with an ohmmeter and compare to the specified value (P1-30); check connections to terminals BR+ and BR-.
4. Check parameter P1-30 (Braking Resistor Ohms) and P1-31 (Braking Resistor Power) for correct configuration relative to the installed resistor.
5. Monitor DC bus voltage (A01-01) in real-time during operation to identify when and under what conditions the warning triggers.