Overcurrent

What does %c mean?

This protective fault indicates that the Inverter output current instantaneously exceeded 250% of the rated amperage. Common causes include a short circuit or ground fault on the output side, excessive load inertia, acceleration/deceleration times set too short, use of a special motor, starting the motor during free running, or operating a magnetic contactor on the output side. Unresolved overcurrent can severely damage the inverter's output stage or connected motor.

• Short circuit between two or more output phases (U, V, W) or a phase-to-ground fault on the motor cable or within the motor windings.
• Motor shaft locked or experiencing severe mechanical binding, causing an instantaneous high current draw upon start or during operation.
• Rapid acceleration with an excessively large load inertia, causing the inverter's output current to exceed its instantaneous limit.
• Inverter acceleration time parameter (e.g., P1-07) set too short for the connected load and application requirements.
• Incorrect motor parameters (e.g., P2-01 for motor rated voltage, P2-03 for motor rated current) entered into the inverter, leading to improper current control.

Click steps to track your progress.

1. 1

   Power down the inverter and disconnect the motor cables (U, V, W) from the inverter output terminals. Measure resistance between phases and from each phase to ground on the motor cable and motor windings using a megohmmeter (megger).

2. 2

   Manually check the motor shaft for free rotation; ensure no mechanical binding, seized bearings, or external obstructions preventing movement.

3. 3

   Increase the inverter's acceleration time parameter (e.g., P1-07) in small increments to reduce the initial current demand during motor start-up.

4. 4

   Verify all motor nameplate data (voltage, current, frequency, RPM, poles) against the inverter's motor parameter settings (e.g., P2-01 to P2-06) for accuracy.

5. 5

   Measure the motor's running current using a clamp meter on one output phase (U, V, or W) and compare it to the inverter's rated output current and the motor's full load amperage.

6. 6

   Inspect the mechanical load connected to the motor for any sudden increases in torque requirement or potential jamming.