Cause : Excessive intermediate circuit DC voltage. DC overvoltage trip limit is 1.3 × 1.35 × U1max, where U1max is maximum value of supply voltage range. For 400 V units, U1max is 415 V. For 500 V units, U1max is 500 V. For 690 V units, U1max is 690 V. Actual voltage in intermediate circuit corresponding to the supply voltage trip level is 728 V DC for 400 V units, 877 V DC for 500 V units, and 1210 V DC for 690 V units.

Check that overvoltage controller is on (parameter 20.05).
Check supply voltage for static or transient overvoltage.
Check brake chopper and resistor (if used).
Check deceleration time.
Use coast-to-stop function (if applicable).
Retrofit frequency converter with brake
chopper and brake resistor.