Code

Name

Causes

Possible Solutions

Uv

DC Bus Undervoltage

The drive input power voltage is changing too much.

  • Use a better power supply voltage to align with the drive rated voltage.

  • Make the drive input power stable.

  • If there is not a fault with the input power supply, examine the magnetic contactor on the main circuit side for faults.

A phase loss occurred 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.

Examine for loose screws and tighten them as specified by the tightening torque values in the manual.

There was a loss of power.

Use a better power supply.

The main circuit capacitors have deteriorated.

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.

Measure the ambient temperature of the drive.

The Charge LED is broken.

Replace the board or the 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 set to H2-01 to H2-03 = 10 [MFDO Function Selection = Alarm] will activate.