Code

Name

Causes

Possible Solutions

ov

Overvoltage

The deceleration time is too short and too much regenerative energy is flowing back into the drive.

  • Increase the values set in C1-02, C1-04, C1-06, or C1-08 [Deceleration Times].

  • Connect a dynamic braking option to the drive.

  • Perform Deceleration Rate Tuning.

The acceleration time is too short.

  • Make sure that sudden drive acceleration does not cause the fault.

  • Increase the values set in C1-01, C1-03, C1-05, or C1-07 [Acceleration Times].

  • Increase the value set in C2-02 [S-Curve Time @ End of Accel].

  • Set L3-11 = 1 [Overvoltage Suppression Select = Enabled].

The braking load is too large.

Connect a dynamic braking option to the drive.

There are surge voltages in the input power supply.

Connect a DC reactor to the drive.

Note:

If you turn the phase advancing capacitors ON and OFF and use thyristor converters in the same power supply system, there can be surge voltages that irregularly increase the input voltage.

The drive output cable or motor is shorted to ground (the current short to ground is charging the main circuit capacitor of the drive through the power supply).

  1. Examine the motor main circuit cable, terminals, and motor terminal box, and then remove ground faults.

  2. Re-energize the drive.

If the drive detects ov in these conditions, the speed search-related parameters are incorrect:

  • During speed search

  • During momentary power loss recovery

  • When the drive starts again automatically

  • When you use an IE3 premium efficiency motor

  • Examine the settings for all speed search related parameters.

  • Set b3-19 ≠ 0 [Speed Search Restart Attempts ≠ 0 times].

  • Adjust b3-03 [Speed Search Deceleration Time].

  • Do Stationary Auto-Tuning for Line-to-Line Resistance and then set b3-24 = 1 [Speed Search Method Selection = Speed Estimation].

  • Use these values to adjust the parameters.

    • b3-03 [Speed Search Deceleration Time] = default value × 2

    • L2-03 [Minimum Baseblock Time] = default value × 2

    • L2-04 [Powerloss V/f Recovery Ramp Time] = default value × 2

The power supply voltage is too high.

Decrease the power supply voltage to match the drive rated voltage.

The braking resistor or braking resistor unit wiring is incorrect.

Correct wiring errors in the connection to the braking resistor or braking resistor unit.

Electrical interference caused a drive malfunction.

  • Examine the control circuit lines, main circuit lines, and ground wiring, and decrease the effects of electrical interference.

  • Make sure that a magnetic contactor is not the source of the electrical interference, then use a Surge Protective Device if necessary.

The load inertia is set incorrectly.

  • Examine the load inertia settings with KEB, overvoltage suppression, or stall prevention during deceleration.

  • Adjust L3-25 [Load Inertia Ratio] to match the qualities of the machine.

The Short Circuit Braking function used in OLV/PM control method.

Connect a braking resistor to the drive.

There is motor hunting.

  • Set n1-01 = 1 [Hunting Prevention Selection = Enabled] and adjust n1-02 [Hunting Prevention Gain Setting].

  • Adjust n2-02 [Automatic Freq Regulator Time 1] and n2-03 [Automatic Freq Regulator Time 2].

  • Adjust n8-45 [Speed Feedback Detection Gain] and n8-47 [Pull-in Current Comp Filter Time].

Speed search does not complete at start when you set A1-02 = 8 [EZ Vector Control] and use an induction motor.

When E9-01 = 0 [Motor Type Selection = Induction (IM)], set b3-24 = 2 [Speed Search Method Selection = Current Detection Speed Search].
Note:

  • The drive detects this error if the DC bus voltage is more than the ov detection level while the drive is running.

  • The ov detection level is approximately 410 V with 200 V class drives. For 400 V class drives, the detection level is approximately 820 V.

  • Do a Fault Reset to clear the fault.

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