Overcurrent During Acceleration

What does E.OC1 mean?

When the inverter's output current rapidly increases to approximately 230% of the rated current during the acceleration phase, the internal protection circuit is triggered, leading to an immediate shutdown of the inverter output. This can indicate excessive load, improper acceleration settings, or an output short-circuit condition. Left unaddressed, this can cause repeated trips, motor damage, or inverter component stress.

• Acceleration time (P1-08) set too short for the motor and load inertia, demanding excessive torque.
• Mechanical binding or jamming in the driven equipment causing high load during startup.
• Motor winding insulation breakdown or phase-to-phase short circuit.
• Loose connections at inverter output terminals (U, V, W) or motor terminal box causing phase imbalance.

Click steps to track your progress.

1. 1

   Increase acceleration time (P1-08) by at least 25% and retest motor startup.

2. 2

   Disconnect the motor from the mechanical load and attempt to run it unloaded; measure motor current during acceleration.

3. 3

   Measure insulation resistance of motor windings to ground using a megohmmeter (>1MΩ) and phase-to-phase resistance with a multimeter.

4. 4

   Inspect and tighten all motor power connections at inverter output terminals (U, V, W) and the motor terminal box.

5. 5

   Verify motor nameplate current matches inverter parameter P0-03 (Motor rated current).