The Delta VFD-B AC motor drive's comprehensive fault diagnostic system is designed to detect faults and activate protective functions to prevent further damage to the system. The digital keypad display is used to display the four most recent faults, which can be read from the keypad or through communication. It's important to wait 5 seconds after a fault has been cleared before performing a reset via the keypad or input terminal to give the system time to stabilize.

There are three methods to reset the Delta VFD-B AC motor drive after solving a fault:

    Pressing the RESET/STOP key on PU01: This method involves physically pressing the RESET/STOP key on the control panel to reset the system.

    Setting an external terminal to "RESET": This method involves setting one of the Pr.04-04 to Pr.04-09 parameters to the value of 05,


oc: and occ:

These are the steps to troubleshoot an Over Current (OC) issue in an AC motor drive that is protected by an Insulated Gate Bipolar Transistor (IGBT). By following these steps, you can identify the cause of the issue and resolve it effectively.

- Verify that the power of the motor matches the output power of the AC motor drive.
- Inspect the connections of the U, V, W wires for any potential short circuits.
- Check the connections between the AC motor drive and the motor for any short circuits and inspect for proper grounding.
- Ensure that the contacts between the AC motor drive and motor are secure.
- Increase the acceleration time to see if this resolves the issue.
- Check for excessive loading conditions on the motor.
- If the issue persists after following the steps above, it may be necessary to send the AC motor drive back to the manufacturer for repair.

ov (ou): These are the steps to troubleshoot an Over Voltage (OV) issue in a DC bus of an AC motor drive. Over voltage occurs when the voltage exceeds its maximum allowable value.

- Verify that the input voltage falls within the rated range for the AC motor drive.
- Look for any possible voltage transients that might have caused the over-voltage.
- Over-voltage in the DC bus can also be a result of motor regeneration. You can increase the deceleration time or add a brake resistor and brake unit to resolve this issue.
- Make sure that the required brake power is within the specified limits.


oH: These are the steps to troubleshoot an Overheating (oH) issue in an AC motor drive. Overheating occurs when the temperature of the heat sink becomes too high.

- Confirm that the ambient temperature is within the specified range for the AC motor drive.
- Ensure that the ventilation holes are not blocked and clear of any obstructions.
- Remove any foreign objects from the heat sinks and inspect for dirty or clogged heat sink fins.
- Check the fan and clean it if necessary.
- Provide adequate space for ventilation to ensure proper air flow.

Lu: These are the steps to troubleshoot a Low Voltage (Lu) issue in an AC motor drive. Low voltage occurs when the DC bus voltage falls below its minimum value.

- Verify that the input voltage falls within the rated input voltage range for the AC motor drive.
- Inspect for any abnormal loads on the motor.
- Ensure that the input power is properly wired to R-S-T (for 3-phase models) and that there is no loss of phase.


oL: These are the steps to troubleshoot an Overload (oL) issue in an AC motor drive. Overload occurs when the drive output current exceeds its maximum value.

- Confirm that the motor is not overloaded and that the load it is handling is within its rated capacity.
- Reduce the torque compensation setting in Pr.7-02.
- Consider using a higher power AC motor drive model if the issue persists.

Note: The AC motor drive is designed to withstand up to 150% of the rated current for a maximum of 60 seconds.


oL1: Overload 1
 These are the steps to troubleshoot an Overload 1 (oL1) issue in an AC motor drive. Overload 1 is an internal electronic overload trip, which occurs when the drive's internal protection circuitry detects excessive current.

- Verify that the motor is not overloaded and that the load it is handling is within its rated capacity.
- Check the electronic thermal overload setting and ensure it is set correctly.
- Consider using a higher power motor to resolve the issue.
- Reduce the current level so that the drive output current does not exceed the value set by the Motor Rated Current Pr.7-00.

oL2: These are the steps to troubleshoot an Overload 2 (oL2) issue in an AC motor drive. Overload 2 is a motor overload, which occurs when the motor is handling a load that exceeds its rated capacity.

- Reduce the load on the motor to bring it within its rated capacity.
- Adjust the over-torque detection setting to an appropriate value using Pr.06-03 to Pr.06-05. This will help ensure that the motor is not overloaded in the future.

CE-: These are the steps to troubleshoot a Communication Error (CE-) issue in an AC motor drive. A Communication Error occurs when there is a problem with the communication between the AC motor drive and the RS485 master.

- Check the RS485 connection between the drive and the master for loose wires and ensure that the wiring is correct.
- Verify that the communication protocol, address, transmission speed, etc. are properly set.
- Ensure that the correct checksum calculation is being used.
- For more information, refer to Group 9 in Chapter 5 of the manual or user guide for the AC motor drive.

oCA: Over-current during acceleration

These are the steps to troubleshoot an Over-current during Acceleration (oCA) issue in an AC motor drive. Over-current during Acceleration occurs when there is an abnormal increase in current during the acceleration phase of the motor.

- Check for possible short-circuits at the motor output, such as poor insulation in the output lines.
- If the torque boost is too high, decrease the torque compensation setting in Pr.7-02.
- If the Acceleration Time is too short, increase it.
- If the AC motor drive output power is too small, replace the drive with a higher power model.

ocd: Over-current during deceleration
These are the steps to troubleshoot an Over-current during Deceleration (ocd) issue in an AC motor drive. Over-current during Deceleration occurs when there is an abnormal increase in current during the deceleration phase of the motor.

- Check for possible short-circuits at the motor output, such as poor insulation in the output lines.
- If the Deceleration Time is too short, increase it.
- If the AC motor drive output power is too small, replace the drive with a higher power model.

ocn: Over-current during constant speed operation
- Make sure that the motor wiring is correct,     without short circuits.
- Check for any loose connections between the AC motor drive and motor.
- Ensure that the motor power corresponds with the AC motor drive output power.
- Reduce the current level so that the drive output current does not exceed the value set by the Motor Rated Current Pr.7-00.

+ Countiune fault code page 2 >>

++ Delta VFD-B User manuals 

++ VFD-B Fault Codes >>

++ VFD-B Fault Codes 2 >>

++ Delta 2 main page

+ VFD main Page

-