Method of Resetting Trip Causes

If your inverter trips due to a malfunction or issue, ensure you remove the cause of the trip before attempting to reset it. Resetting the inverter without addressing the underlying issue will result in repeated trips.

Error Codes and Solutions

To reset the inverter from a trip state, follow these steps:

 OC1, OC1P - Overcurrent During Acceleration (DC Current):

- Causes:
+ Acceleration time #1 (ACC) is too short.
+ Incorrect V/f parameter settings.
+ Motor started during a momentary power failure.
+ Special low impedance motor used.
+ Large manual torque boost value (νb).
+ Ground-fault in output cable or motor.
- Solutions:
+ Extend acceleration time #1 (ACC).
+ Check and adjust V/f parameter.
+ Use F301 (Auto-restart) or F302 (Regenerative power ride-through control).
+ Raise carrier frequency F300.
+ Decrease νb setting value.
+ Check for ground-faults in units and connections.

 OC2, OC2P - Overcurrent During Deceleration (DC Current):

- Causes:
+ Deceleration time #1 (dEC) is too short.
+ Motor started during a momentary power failure.
+ Ground-fault in output cable or motor.
- Solutions:
+ Extend deceleration time #1 (dEC).
+ Use F301 (Auto-restart) or F302 (Regenerative power ride-through control).
+ Check for ground-faults in units and connections.

 OC3, OC3P - Overcurrent During Fixed Speed (DC Current):

- Causes:
+ Rapid load variation.
+ Abnormal load.
+ Ground-fault in output cable or motor.
- Solutions:
+ Reduce load variation.
+ Check the loading unit.
+ Check for ground-faults in units and connections.

Additional Causes for OC1P, OC2P, OC3P

These trip indications can originate from other causes not listed previously, such as:

- Faulty Main Circuit Device: A malfunction in the main circuit.
- Overheat Protection: Activated for power ranges from 5.5 to 15 kW, and 30 kW or more.
- Control Voltage Drop Prevention: Activated for the same power ranges as above.

Solutions:
- Contact a service professional.
- Check the operation of the cooling fan.
- Verify the cooling fan control mode parameter (F620).

Common Indications and Solutions

OCL - Overcurrent (Loaded Side at Start):

- Causes:
+ Faulty wiring or motor insulation.
+ Low motor impedance.
- Solutions:
+ Inspect wiring and insulation.
+ Set output short-circuit detection parameters (F613 and F614) properly.

OCA1, OCA2, OCA3 - Phase Arm Short-Circuit (U-phase, V-phase, W-phase):

- Cause: Abnormality in the respective main circuit device.
- Solution: Contact a service professional.

EPH1 - Phase Failure (Input Side):

- Cause: Missing phase in the main input circuit.
- Solution: Check the connections in the main input circuit.

EPH0 - Phase Failure (Output Side):

- Cause: Missing phase in the main output circuit.
- Solutions:
+ Check the connections in the main output circuit and motor.
+ Select the output phase failure detection parameter (F605) for inspection.

Overvoltage Indications and Solutions

 OP1 - Overvoltage During Acceleration:

- Causes:
+ Abnormal input voltage variations.
- Power-factor improving capacitor toggled.
- Thyristor-connected units sharing the same power supply line.
+ Motor started during a momentary power failure.
- Solutions:
+ Try inserting an input reactor.
+ Use F301 (Auto-restart) and F302 (Regenerative power ride-through control).

 OP2 - Overvoltage During Deceleration:

- Causes:
+ Deceleration time (dEC) is too short, causing excessive regenerated energy.
+ High PBR resistance.
+ Disabled dynamic braking mode (F304).
+ Disabled over-voltage stall protection (F305).
+ Abnormal input voltage variations.
- Solutions:
+ Extend deceleration time (dEC).
+ Install a dynamic braking resistor.
+ Decrease dynamic braking resistance and reset F308.
+ Correctly set F304 and F305.
+ Insert an input reactor if needed.

 OP3 - Overvoltage During Fixed Speed:

- Causes:
+ Abnormal input voltage variations.
- Power capacity of 500 kVA or more.
- Power-factor improving capacitor toggled.
- Thyristor-connected units sharing the same power supply line.
+ Motor exceeds inverter’s output frequency, entering regeneration.
- Solutions:
+ Insert an input reactor.
+ Install a dynamic braking resistor.

Overload Indications and Solutions

 OL1 - Inverter Overloaded:

- Causes:
+ Rapid acceleration.
+ High DC breaking rate.
+ Improper V/f parameter setting.
+ Motor started during a power failure.
+ Excessive load.
- Solutions:
+ Extend acceleration time (ACC).
+ Decrease DC injection braking current (F251) and time (F252).
+ Check and adjust the V/f parameter.
+ Use F301 (Auto-restart) and F302 (Regenerative control).
+ Increase the inverter rating.

 OL2 - Motor Overloaded:

- Causes:
+ Improper V/f parameter setting.
+ Motor lock-up.
+ Continuous low-speed operation.
+ Operating with overload.
- Solutions:
+ Verify and adjust the V/f parameter.
+ Check the loading unit.
+ Properly reset F606 to reduce overload at start-up frequency.

+ Toshiba VFD-A7 User manual >

+ VF-A7 Fault codes 1 >>

+ VF-A7 Fault codes 2 >>

+ VF-A7 Fault codes 3 >>

+ VF-A7 Fault codes 4 >>

////

- Toshiba Homepage <

- VFD Main page <

-