Code

Name

Causes

Possible Solutions

Uv1

DC Bus Undervoltage

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.

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 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 relay or contactor on the soft-charge bypass relay is damaged.

U4-06 [PreChargeRelayMainte] shows the performance life of the soft-charge bypass relay. If U4-06 is more than 90%, replace the board or the drive. For information about replacing the board, contact Yaskawa or your nearest sales representative.

Note:
  • The drive detects this error if the DC bus voltage decreases below the level set in L2-05 [Undervoltage Detection Lvl (Uv1)] while the drive is running.

  • The Uv1 detection level is approximately 190 V for a 200 V class drives. The detection level is approximately 380 V for 400 V class drives. The detection level is approximately 350 V when E1-01 [Input AC Supply Voltage] < 400.

  • Do a Fault Reset to clear the fault.

  • Fault trace is not available for this fault.

  • L5-08 [Fault Reset Enable Select Grp2] disables the Auto Restart function.