It.AC Output current overload timed out (I2t) - accumulator value can be seen in Pr 4.19

- Ensure the load is not jammed.
- Check that the load on the motor has not changed.
- If seen during autotune in servo mode, ensure the motor rated current in Pr 0.46 (Pr 5.07) or Pr 21.07 is less than or equal to the Heavy Duty current rating of the drive.
- Adjust the rated speed parameter (for closed-loop vector only).
- Check for noise in the feedback device signal.
- Check the mechanical coupling of the feedback device.

It.br Braking resistor overload timed out (I2t) – accumulator value can be seen in Pr 10.39

- Ensure that the values entered in Pr 10.30 and Pr 10.31 are correct.
- Increase the power rating of the braking resistor and adjust Pr 10.30 and Pr 10.31.
- If an external thermal protection device is being used and the software overload protection for the braking resistor is not required, disable the trip by setting Pr 10.30 or Pr 10.31 to 0.

L.SYnC Drive failed to synchronize to the supply voltage in Regen mode

- Refer to the Diagnostics chapter in the Unidrive SP Regen Installation Guide.

O.CtL Drive control board over temperature

- Check that the enclosure/drive fans are functioning correctly.
- Check the enclosure ventilation paths.
- Check the enclosure door filters.
- Check the ambient temperature.
- Reduce the drive switching frequency.

O.ht1 Power device over temperature (based on thermal model)

- Reduce the drive switching frequency.
- Reduce the duty cycle.
- Decrease acceleration/deceleration rates.
- Reduce motor load.

O.ht2 Heatsink over temperature

- Check that the enclosure/drive fans are functioning correctly.
- Check the enclosure ventilation paths.
- Check the enclosure door filters.
- Increase ventilation.
- Decrease acceleration/deceleration rates.
- Reduce the drive switching frequency.
- Reduce the duty cycle.
- Reduce motor load.

Oht2.P Power module heatsink over temperature

- Check that the enclosure/drive fans are functioning correctly.
- Check the enclosure ventilation paths.
- Check the enclosure door filters.
- Increase ventilation.
- Decrease acceleration/deceleration rates.
- Reduce the drive switching frequency.
- Reduce the duty cycle.
- Reduce motor load.

O.ht3 Drive over-temperature (based on thermal model)

- The drive will attempt to stop the motor before tripping. If the motor does not stop within 10 seconds, the drive will trip immediately.
- Check that the enclosure/drive fans are functioning correctly.
- Check the enclosure ventilation paths.
- Check the enclosure door filters.
- Increase ventilation.
- Decrease acceleration/deceleration rates.
- Reduce the duty cycle.
- Reduce motor load.

Oht4.P Power module rectifier over temperature or input snubber resistor over temperature (size 4 and above)

- Check for supply imbalance.
- Check for supply disturbances such as notching from a DC drive.
- Check that the enclosure/drive fans are functioning correctly.
- Check the enclosure ventilation paths.
- Check the enclosure door filters.
- Increase ventilation.
- Decrease acceleration/deceleration rates.
- Reduce the drive switching frequency.
- Reduce the duty cycle.
- Reduce motor load.

OI.AC Instantaneous output over-current detected: output current greater than 225%

- Acceleration/deceleration rate is too short.
- If seen during autotune, reduce the voltage boost (Pr 5.15).
- Check for short circuits in the output cabling.
- Check the integrity of motor insulation.
- Check the feedback device wiring.
- Check the mechanical coupling of the feedback device.
- Check for noise in the feedback signals.
- Ensure that the motor cable length is within limits for this frame size.
- Reduce the speed loop gain parameters – Pr 3.10, Pr 3.11, and Pr 3.12 (for servo modes only).
- Has the offset measurement test been completed? (for servo modes only).
- Reduce the current loop gain parameters – Pr 4.13 and Pr 4.14 (for closed-loop vector and servo modes).

OIAC.P Power module over-current detected from module output currents

- Acceleration/deceleration rate is too short.
- If seen during autotune, reduce the voltage boost (Pr 5.15).
- Check for short circuits in the output cabling.
- Check the integrity of motor insulation.
- Check the feedback device wiring.
- Check the mechanical coupling of the feedback device.
- Check for noise in the feedback signals.
- Ensure that the motor cable length is within limits for this frame size.
- Reduce the speed loop gain parameters – Pr 3.10, Pr 3.11, and Pr 3.12 (for closed-loop vector and servo modes).
- Has the offset measurement test been completed? (for servo modes only).
- Reduce the current loop gain parameters – Pr 4.13 and Pr 4.14 (for closed-loop vector and servo modes).

OI.br Braking transistor over-current detected: short circuit protection for the braking transistor activated

- Check the braking resistor wiring.
- Ensure that the braking resistor value is greater than or equal to the minimum resistance value.
- Check the insulation of the braking resistor.

OIbr.P Power module braking IGBT over-current

- Check the braking resistor wiring.
- Ensure that the braking resistor value is greater than or equal to the minimum resistance value.
- Check the insulation of the braking resistor.

OIdC.P Power module over-current detected from IGBT on state voltage monitoring

- Vce IGBT protection activated.
- Check the motor and cable insulation.

O.Ld1 Digital output overload: total current drawn from 24V supply and digital outputs exceeds 200mA

- Check the total load on the digital outputs (terminals 24, 25, 26) and the +24V rail (terminal 22).

O.SPd Motor speed has exceeded the over speed threshold

- Increase the over-speed trip threshold in Pr 3.08 (for closed-loop vector and servo modes only) (closed-loop vector RFC mode).
- Speed has exceeded 1.2 x Pr 1.06 or Pr 1.07 (in open-loop mode).
- Reduce the speed loop P gain (Pr 3.10) to reduce the speed overshoot (for closed-loop vector and servo modes only) (closed-loop vector RFC mode).