PCU CEMF FAULT

What does 408 mean?

The Counter Electromotive Force (CEMF) of the motor exceeded 118% of the rated AC voltage to the drive. This fault indicates a miss-operation causing speed overshoot. This fault causes a drive shutdown to prevent fuse blowing.

• 3 Phase Input AC Line Voltage is low.
• Incorrect motor field current setting or field regulator causing excessive CEMF.
• Excessive drive speed causing overshoot.
• Incorrect motor field control dynamic tuning adjustments.

Click steps to track your progress.

1. 1

   Check and correct the 3 Phase Input AC Line Voltage.

2. 2

   Adjust velocity regulator tuning to prevent CEMF overshoot.

3. 3

   Review and verify settings for parameters #49, #50, #51, #52, #54, and #55.

4. 4

   Check and correct motor field control dynamic tuning to prevent overshoot.