Code

Name

Causes

Possible Solutions

Uv

Undervoltage

The drive input power voltage is changing too much.

  • Examine the input power for problems.

  • Make the drive input power stable.

  • If the input power supply is good, examine the magnetic contactor on the main circuit side for problems.

There is a phase loss in the drive input power.

Correct errors with the wiring for main circuit drive input power.

There is loose wiring in the drive input power terminals.

Tighten the terminal screws to the correct tightening torque.

There was a loss of power.

Use a better power supply.

The main circuit capacitors have become unserviceable.

Examine the capacitor maintenance time in monitor U4-05 [CapacitorMaintenance]. If U4-05 is more than 90%, replace the control board or the drive. For information about replacing the control board, contact Yaskawa or your nearest sales representative.

The drive input power transformer is too small and voltage drops when the power is switched on.

  • Check for an alarm when a molded-case circuit breaker, Leakage Breaker (ELCB, GFCI, or RCM/RCD) (with overcurrent protective function), or magnetic contactor is ON.

  • Check the capacity of the drive power supply transformer.

Air inside the drive is too hot.

Check the ambient temperature of the drive.

The Charge LED is broken.

Replace the control board or the entire drive. For information about replacing the control board, contact Yaskawa or your nearest sales representative.
Note:

  • The drive detects this error if one of these conditions is correct when the Run command has not been input (while the drive is stopped).

    • The DC bus voltage < L2-05 [Undervoltage Detection Lvl (Uv1)].

    • The Contactor that prevents inrush current in the drive was opened.

    • There is low voltage in the control drive input power.

  • If the drive detects this error, the terminal assigned to H2-01 to H2-04 = 10 [MFDO Function Select = Alarm] will be ON.