Undervoltage

What does Undervoltage mean?

The voltage at the main circuit power supply has dropped below an acceptable operating level. This can be caused by issues in the incoming power supply line, insufficient capacity, or a fault within the power supply itself, leading to insufficient power for the inverter and potential damage if the voltage fluctuates excessively. The inverter output is shut off.

• Sag or complete loss of one or more phases in the incoming AC main power supply (e.g., R/L1, S/L2, T/L3 terminals).
• Insufficient power supply capacity for the driven load, causing voltage drops during peak current demand.
• Loose or corroded connections in the main power circuit, leading to voltage drop under load.
• Faulty main circuit capacitors within the inverter, affecting DC bus voltage regulation.

Click steps to track your progress.

1. 1

   Measure the incoming AC line voltage at the inverter's main input terminals (R/L1, S/L2, T/L3) using a multimeter or power quality analyzer.

2. 2

   Check for loose connections or corrosion on the main power wiring terminals, both at the inverter and upstream circuit breakers/contactors.

3. 3

   Verify the capacity of the upstream transformer and circuit breaker to ensure they can adequately supply the inverter and motor.

4. 4

   Monitor the DC bus voltage (e.g., using Pr. 08 "DC Bus Voltage" monitor function) during operation to observe sag trends.

5. 5

   Consult an electrician to inspect the facility's power distribution system for sags or imbalances affecting the inverter's supply.