Undervoltage Alarm

What does UV mean?

This is a warning displayed on the digital operator during a momentary power loss event. It indicates that incoming AC power has been interrupted, but the drive's control power supply is still being maintained. The alarm signifies the drive is in a ride-thru state and will precede a UV1 fault if power is not restored within the configured ride-thru time (L2-02).

• Momentary interruption or sag of the incoming AC power supply to the drive, lasting for a short duration.
• Loss of one or more input phases for a very brief period due to grid instability or upstream protection.
• Weak or unstable incoming AC power supply, making it susceptible to transient voltage dips.
• Auxiliary control power supply (if external) experiencing a brief dip or interruption.
• The drive's internal ride-through capability (e.g., L2-01 setting) is being utilized during a power event.

Click steps to track your progress.

1. 1

   1. Monitor the incoming AC line voltage at R/L1, S/L2, T/L3 terminals with a power quality analyzer to detect voltage sags.

2. 2

   2. Inspect upstream circuit breakers and fuses for signs of intermittent tripping or loose connections.

3. 3

   3. Confirm all input power wiring connections at the drive are secure and free of corrosion.

4. 4

   4. Verify the drive's ride-through settings (e.g., L2-01) are configured appropriately for the application's power stability.

5. 5

   5. Consider installing a UPS (Uninterruptible Power Supply) for the control circuit or the entire drive if power quality is consistently poor.