Excessive Speed Deviation

What does E81 mean?

This fault is triggered when the motor speed deviates excessively from the commanded speed, exceeding a set threshold (P027), often in applications with encoder feedback. This indicates a loss of control, where the motor is either running too fast or too slow relative to the commanded reference, causing an inverter trip to prevent instability.

Additional Steps

Steps 1–2 are listed in Priority Fix.

1. 3

   Review the load conditions on the motor; excessive or fluctuating loads can cause speed deviations that exceed the set limits.

2. 4

   Check the PID control parameters (A072, A073, A074) if PID is in use, as an untuned loop can cause oscillations or deviations from setpoint.

3. 5

   Ensure the motor and inverter capacities are matched to the application to handle transient loads effectively without losing control.