OPL Output Phase Loss fault in delta drive

OPL Output Phase Loss fault in delta drive troubleshooting

Description

OPL signifies the drive is not detecting current on one of the output phases (U, V, W). This usually happens when the circuit to the motor is open.

Causes

1. Disconnected Wire: A cable has come loose at the motor or drive end.
2. Motor Winding Open: The internal winding of the motor has burnt open.
3. Output Contactor: If there is a contactor or switch between the drive and motor, it might be open or have burnt contacts.
4. Drive Failure: One of the drive's output IGBTs is not firing.

Solution

Check the path to the motor:
1. Resistance Check: With power off, measure resistance between U-V, V-W, and W-U. All should be low and balanced. An infinite reading (OL) means a broken wire or winding.
2. Bypass Switches: Remove any maintenance switches or contactors between VFD and motor to test direct connection.
3. Check Parameter: Ensure "Output Phase Loss Detection" is enabled/configured correctly for the motor size. A very small motor on a large drive might trigger false OPL (current too low to detect).