Cause : Motor overload comes when he motor may be tasked with moving a load that exceeds its rated capacity. This can lead to various issues, including overheating, reduced performance, and even damage to the motor. 

Er.620 fault in inovance IS650 servo drive indicates Motor overload condition. This means a motor is required to produce more torque than it is rated for. 

1. Temporarily reduce the load on the motor to see if the overload persists.
2. Inspect the motor, couplings, and bearings for any signs of wear or damage.
3. Ensure that the power supply voltage and current are sufficient.
4. Double-check the current limits, PID parameters, and other relevant settings.