Overcurrent Condition (Operation, Adv. Code 1)

What does 18 mean?

This fault indicates that the drive detected an overcurrent condition during normal operation, meaning the motor current exceeded the safe operating limits of the drive's power devices. This can be caused by excessive mechanical load, incorrect motor parameters, sudden load changes, or mechanical binding. This trips the drive to protect itself and the motor.

• Motor mechanical overload due to binding bearings, gearbox seizure, or an abrupt increase in load on the driven machine.
• Motor phase-to-phase or phase-to-ground short circuit in the motor windings or damage to the motor cable insulation.
• Drive parameters related to motor data (e.g., P2-01 Motor Rated Current, P2-03 Motor Rated Voltage) are incorrectly configured, leading to erroneous current monitoring.
• Acceleration/deceleration ramps (P1-03 Acceleration Time, P1-04 Deceleration Time) set too short for the inertia of the driven load, causing high transient currents.
• Drive's output power devices (IGBTs) or their gate driver circuits malfunctioning, leading to uncontrolled current output or phase imbalance.
• Insufficient motor flux due to low voltage-to-frequency ratio (V/Hz) settings (e.g., P1-11 V/Hz curve) at higher operating frequencies, increasing magnetizing current.

Click steps to track your progress.

1. 1

   Measure the motor winding resistance phase-to-phase (U-V, V-W, W-U) using an ohmmeter and phase-to-ground with a megohmmeter (e.g., 500VDC). Compare readings to motor specifications (e.g., >1MOhm to ground).

2. 2

   Disconnect the motor from the driven mechanical load. Operate the motor unloaded and monitor the drive's output current to determine if the fault is motor/drive related or mechanical load related.

3. 3

   Verify all motor data parameters in the drive (P2-01 Motor Rated Current, P2-02 Motor Rated Power, P2-03 Motor Rated Voltage, P2-04 Motor Rated Frequency) precisely match the motor nameplate data.

4. 4

   Increase the drive's acceleration time (P1-03) and deceleration time (P1-04) by at least 25% to reduce the current peaks during speed changes.

5. 5

   Monitor the drive's actual output current (display parameter P1-10 Output Current) during various operational states (start, run, stop) to identify the specific conditions under which the overcurrent occurs.

6. 6

   Inspect all motor connections at the drive's output terminals (U, V, W) and within the motor's terminal box for loose connections, signs of overheating, or insulation damage.