Yaskawa GA500 fault ov: Overvoltage
Fault ov on a Yaskawa GA500 is Overvoltage: the DC bus voltage rose above the ov detection level while the drive was running, approximately 410 V for 200 V class drives and 820 V for 400 V class drives. The usual cause is regenerated energy from a deceleration that is too short.
Diagnose this with AI
Try Free Drive Diagnostic Upload a keypad photo, the fault history or a parameter export from your Yaskawa GA500. InduQT compares the evidence and suggests the next useful checks.
When it happens
- Deceleration or stopping
- End of a fast acceleration (speed overshoot)
- Speed search or restart after a power loss
- Any state if the supply has surges
Likely causes and checks
1Deceleration time too short
- Points to it
- Trips only while slowing down; U2-08 DC bus at fault is high.
- Check
- Increase C1-02 (or C1-04/C1-06/C1-08), connect a dynamic braking option, or run Deceleration Rate Tuning.
2Stall prevention during decel set wrong
- Points to it
- L3-04 set for a braking resistor that is not fitted, or the reverse.
- Check
- Check L3-04 [Stall Prevention during Decel]; the manual gives 0 with a braking option and 3 if ov occurs with a DB resistor.
3Speed overshoot at the end of acceleration
- Points to it
- Trips just after reaching speed on a fast ramp.
- Check
- Increase C1-01 and C2-02 [S-Curve Time @ End of Accel], or set L3-11 = 1 [Overvoltage Suppression].
4Braking resistor wiring wrong or braking load too large
- Points to it
- Resistor fitted but trips continue.
- Check
- Check the braking resistor or unit wiring and its sizing for the braking load.
5Supply surges or high supply voltage
- Points to it
- Trips at constant speed; phase-advancing capacitors or thyristor converters share the supply.
- Check
- Measure the supply; Yaskawa suggests a DC link choke for surges.
6Ground fault in output cable or motor
- Points to it
- ov together with GF or oC history.
- Check
- Inspect and megger the motor cable, terminals and terminal box with the motor disconnected.
Telling it apart
- An ov with the ALM LED flashing is the alarm form (drive keeps running); steady ALM LED is the fault that stopped the drive.
- Trips during decel point to C1-02, L3-04 and braking. Trips at constant speed or while idle point to the supply.
- V1000 equivalence: the V1000 Technical Manual lists ov (Overvoltage) at approximately 410 V (200 V class) and 820 V (400 V class, 740 V when E1-01 is below 400), with the same decel-time, braking and supply causes.
Relevant parameters
| Parameter | Name | Why it matters |
|---|---|---|
| C1-02 | Deceleration Time 1 | Default 10.0 s; C1-04/C1-06/C1-08 are alternates. |
| L3-04 | Stall Prevention during Decel | Default 1; set 0 with a dynamic braking option. |
| L3-11 | Overvoltage Suppression Select | 1 = enabled; default 0. |
| L5-08 | Fault Reset Enable Select Grp2 | Controls whether auto restart applies to ov. |
Evidence to collect
- U2-08 DC bus voltage at fault and U2-04 output frequency
- C1-01/C1-02, C2-02, L3-04, L3-11 settings
- Braking resistor model and wiring
- Measured supply voltage
- Whether the trip followed speed search or a power loss
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