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What is the SOF (Overspeed) fault on the Altivar Process Drive?

What is the SOF (Overspeed) fault on the Altivar Process Drive?

Product Line:
Altivar Process Drive (ATV630, ATV930, ATV650, ATV950, ATV660, ATV960, ATV680, ATV980)

All serial numbers for Altivar Process Drive


This fault appears when an overspeed is present on the drive.

Probable Cause
  • Instability or driving load too high
  • In the Motor parameters menu (5 Complete Settings -> 5.2 Motor parameters):
    •  Try changing the [Dual rating] to Heavy Duty
    •  Try changing the [Motor control type] to U/F VC Standard (available on the ATV6xx)
  • Check the motor, gain and stability parameters.
  • Check the size of the motor/inverter/load.
  • Add a braking resistor.

Note: We've seen a few instances where just changing the two parameters in the Motor parameters menu have corrected the issue. However, please be aware that changing the drive to heavy duty de-rates the drive by one HP class.
Example: A 50HP drive would now be a 40HP drive
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