Polarity Judge Timeout

What does dv7 mean?

This fault indicates the drive could not detect the motor's polarity within a pre-set length of time during startup or operation. This is typically caused by a disconnection in the motor coil winding or loose screws on the drive's output terminals. Failure to detect polarity prevents the drive from properly controlling the motor, making operation impossible.

• Open circuit in one or more motor phases (U, V, W windings) due to a break.
• Loose or disconnected motor terminal wiring at the drive (T1, T2, T3) or the motor itself.
• Internal motor winding short or inter-turn short circuit preventing proper field establishment.
• Incorrect motor parameters (e.g., P1-01 for motor rated power, P1-02 for motor rated voltage) preventing proper motor model initialization.
• Drive internal current measurement circuit failure (less common but possible).

Click steps to track your progress.

1. 1

   1. Disconnect the motor from the drive output terminals (U, V, W or T1, T2, T3).

2. 2

   2. Measure the resistance between each motor phase winding (U-V, V-W, W-U) using a multimeter; readings should be balanced.

3. 3

   3. Measure the insulation resistance from each motor phase (U, V, W) to motor ground using a megohmmeter (megger) at 500VDC (should be >100M Ohms).

4. 4

   4. Verify all motor cable connections at the drive (T1, T2, T3) and the motor terminal box are tight and secure.

5. 5

   5. Check motor parameters P1-01 to P1-08 against the motor nameplate data for exact match.

6. 6

   6. If a spare motor is available, connect it to the drive and attempt to run to isolate the fault to the motor or the drive.