Overcurrent Protection During Deceleration

What does E02. mean?

This fault indicates an excessive current flow through the inverter during motor deceleration. Common causes include overly rapid deceleration settings, the application of mechanical brakes during deceleration, or high inertia loads. The inverter trips when the current exceeds roughly 200% of its rated output to safeguard its internal power circuitry.

• Deceleration time parameter (P1-05) is set too short for the inertia of the load, causing excessive regenerative energy.
• Braking resistor connection fault or incorrect resistance value (e.g., open circuit, wrong Ohm rating) preventing energy dissipation.
• Internal regenerative braking transistor (IGBT) failure or gate drive circuit issue.
• Sudden mechanical resistance or braking applied externally while the inverter is actively decelerating the motor.
• Application where external forces (e.g., gravity, another drive) are driving the motor during deceleration.

Click steps to track your progress.

1. 1

   Increase the deceleration time parameter (P1-05) in 0.5-second increments and retest operation to allow for smoother deceleration.

2. 2

   Verify the braking resistor is correctly connected to P/+2 and B1 terminals and measure its resistance with an ohmmeter; compare to inverter specifications.

3. 3

   Monitor the DC bus voltage (d001) during deceleration to observe if it exceeds the overvoltage trip threshold (e.g., 780VDC for 400V class).

4. 4

   Inspect the external mechanical braking system (if any) to ensure it does not engage prematurely during inverter-controlled deceleration.

5. 5

   Check the regenerative braking usage rate parameter (b090) to ensure it is appropriately configured for the application and resistor.