Hi everyone,

OC 1, OC 1P: Overcurrent during acceleration (DC section)
- The acceleration time ACCACC is too short.
- The V/f selection is incorrect.
- Start was attempted on a rotating motor after a momentary power failure.
- Is a special (low impedance) motor being used?

    Solutions:
- Increase the acceleration time ACCACC.
- Check the V/f pattern setting.
- Use auto-restart or regeneration power ride-through control.
- Try inserting an AC reactor on the output.
- Try increasing the carrier frequency.

OC 2, OC 2P: Overcurrent during deceleration (DC section)
- The deceleration time dECdEC is too short.

    Solutions:
- Increase the deceleration time dECdEC.

OC 3, OC 3P: Overcurrent during constant speed run (DC section)
- The load changed suddenly.
- The load is faulty.

    Solutions:
- Reduce the load fluctuations.
- Check the load equipment.

Note: Additional Causes for OC 1P, OC 2P, and OC 3P
- A main circuit power transistor is faulty.
- The overheating protection has functioned (5.5~30kW).
- The control power supply undervoltage protection has functioned (5.5~30kW).

    Solutions:
- Refer to OCROCR.
- Refer to OHOH.
- Refer to UPUP, POFFPOFF, NOFFNOFF.

OCL: Overcurrent (overcurrent on load-side during start-up)
- The output main circuit wiring or motor insulation is faulty.
- The motor impedance is too small.

    Solutions:
- Check the condition of the wiring and insulation.
- Change the setting of the output short circuit detection selection OLLSOLLS.

OCA 1: U-phase armature short circuit
- The main circuit U-phase power transistor is faulty.

    Solutions:
- Check the main circuit U-phase power transistor.

OCA 2: V-phase armature short circuit
- The main circuit V-phase power transistor is faulty.

    Solutions:
- Check the main circuit V-phase power transistor.
- The transistor element must be replaced.

OCA 3: W-phase armature short circuit
- The main circuit W-phase power transistor is faulty.

    Solutions:
- Check the main circuit W-phase power transistor.
- The transistor element must be replaced.

OP 1: Overvoltage during acceleration
- The input voltage fluctuated abnormally.
+ The power source capacity is 500kVA or more.
+ Power-factor improvement capacitors went on-line/off-line.
+ A device using thyristors is connected to the same power line.
- Start was attempted on a rotating motor after a momentary power failure, etc.

    Solutions:
- Try inserting an input AC reactor.
- Use auto-restart or regeneration power ride-through control.

OP 2: Overvoltage during deceleration
- The acceleration time dECdEC is too short. (The amount of regenerated power is too large.)
- The DBR resistance value PBrPBr is too large.
- The dynamic braking function PBrPBr is OFF.
- OP stall OPSSOPSS is OFF.
- The input voltage fluctuated abnormally.
+ The power source capacity is 500kVA or more.

    Solutions:
- Increase the deceleration time dECdEC.
- Install a dynamic braking resistor.
- Decrease the dynamic braking resistance value PBrPBr.
- Select the dynamic braking function PBrPBr.
- Select OP stall OPSSOPSS.
- Try inserting an input AC reactor.

OP 3: Overvoltage during constant speed run
- The input voltage fluctuated abnormally.
+ The power source capacity is 500kVA or more.
+ Power-factor improvement capacitors went on-line/off-line.
+ A device using thyristors is connected to the same power line.
- The motor is rotating at a frequency higher than the inverter output frequency due to a force on the load and is in a regenerative state.
+ There are multiple mechanically-coupled motors.
+ The load undergoes piston-type cyclic movement.

    Solutions:
- Try inserting an input AC reactor.
- Change the load so that a regenerative state is not entered.
- Install a dynamic braking resistor.

OLIn: Inverter overload
- Sudden motor acceleration was attempted.
- The DC injection current (time) is set too high (long).
- Start was attempted on a rotating motor after momentary power failure, etc.
- The load is too large.

    Solutions:
- Increase the acceleration time ACCACC.
- Decrease the DC injection current dCIdCI and DC injection time dCIdCI.
- Use auto-restart or regeneration power ride-through control.
- Increase the inverter rating.

+ Toshiba VF-A5 User Manual  >>

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+ VF-A5 Fault codes 3 >>

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