OP (OP1, OP2, OP3) Overvoltage (DC Bus) fault in Toshiba drive
OP (OP1, OP2, OP3) Overvoltage (DC Bus) fault in Toshiba drive
Description The Overvoltage (OP) fault indicates that the DC bus voltage inside the drive has exceeded the safety threshold (typically around 400V for 230V class drives, or 800V for 460V class drives). The DC bus is the energy reservoir of the drive. This fault can happen when the drive is stopped (due to input spikes) but most commonly occurs during deceleration (OP2). When a motor decelerates, it acts as a generator, sending energy back into the drive (regeneration). If the drive cannot absorb or dissipate this energy, the voltage rises until it trips. Causes
1. Deceleration Time: The DEC time is too short. The drive is trying to stop a heavy load faster than the regenerative energy can be dissipated.
2. High Input Voltage: Power surges or capacitor switching at the utility level causing spikes on the input lines.
3. Overhauling Load: The load is spinning the motor faster than the drive frequency (e.g., a downhill conveyor or an unmatched fan).
4. Braking Circuit Failure: If a braking resistor is installed, it may be open-circuit or the braking chopper transistor is blown. Solution The most immediate fix for an OP2 fault during stopping is to increase the Deceleration Time (DEC). By allowing the motor to coast to a stop more slowly, the regenerative energy is returned at a lower rate, preventing the DC bus from spiking.
If the application requires a fast stop (e.g., a saw or emergency process), you cannot simply increase DEC time. In this case, you must install a Dynamic Braking Resistor (DBR). This resistor connects to the PA/+ and PB terminals and burns off the excess voltage as heat. Ensure the drive parameter for "Dynamic Braking Selection" is enabled so the chopper circuit engages.
If the fault occurs while the drive is idle (OP1), measure your incoming line voltage. If you are in an area with unstable power grids or power factor correction capacitors nearby, you may need an AC Line Reactor or an Isolation Transformer on the input side to dampen voltage spikes.
For overhauling loads (like a fan spinning backward due to draft before starting), enable "Catch on Fly" or "Speed Search" parameters. This allows the drive to read the spinning motor speed and catch it, rather than trying to force it to zero and causing a voltage spike.
Description The Overvoltage (OP) fault indicates that the DC bus voltage inside the drive has exceeded the safety threshold (typically around 400V for 230V class drives, or 800V for 460V class drives). The DC bus is the energy reservoir of the drive. This fault can happen when the drive is stopped (due to input spikes) but most commonly occurs during deceleration (OP2). When a motor decelerates, it acts as a generator, sending energy back into the drive (regeneration). If the drive cannot absorb or dissipate this energy, the voltage rises until it trips. Causes
1. Deceleration Time: The DEC time is too short. The drive is trying to stop a heavy load faster than the regenerative energy can be dissipated.
2. High Input Voltage: Power surges or capacitor switching at the utility level causing spikes on the input lines.
3. Overhauling Load: The load is spinning the motor faster than the drive frequency (e.g., a downhill conveyor or an unmatched fan).
4. Braking Circuit Failure: If a braking resistor is installed, it may be open-circuit or the braking chopper transistor is blown. Solution The most immediate fix for an OP2 fault during stopping is to increase the Deceleration Time (DEC). By allowing the motor to coast to a stop more slowly, the regenerative energy is returned at a lower rate, preventing the DC bus from spiking.
If the application requires a fast stop (e.g., a saw or emergency process), you cannot simply increase DEC time. In this case, you must install a Dynamic Braking Resistor (DBR). This resistor connects to the PA/+ and PB terminals and burns off the excess voltage as heat. Ensure the drive parameter for "Dynamic Braking Selection" is enabled so the chopper circuit engages.
If the fault occurs while the drive is idle (OP1), measure your incoming line voltage. If you are in an area with unstable power grids or power factor correction capacitors nearby, you may need an AC Line Reactor or an Isolation Transformer on the input side to dampen voltage spikes.
For overhauling loads (like a fan spinning backward due to draft before starting), enable "Catch on Fly" or "Speed Search" parameters. This allows the drive to read the spinning motor speed and catch it, rather than trying to force it to zero and causing a voltage spike.
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