Cause : Current limit comes when the current being drawn by the load or motor connected to the inverter has exceeded the preset current limit. 

A501 alarm in siemens V20 Drive indicate current limit condition. This means the motor's current consumption exceeds a predefined limit, the drive will activate this alarm, often resulting in a reduction of output frequency or a complete shutdown.

1. Motor power does not correspond to the inverter power
2. Motor leads are too long
3. Earth faults
4. Small motors (120 W) under FCC and light load may cause a high current.
5. Use V/f operation for very small motors.