Cause : No load applied to inverter comes when the inverter is not detecting a motor connected to its output terminals. This means inverter expects a motor to be connected and operational for proper functioning but it doesn't sense any current draw from a motor.

The A0922 alarm in Siemens Micromaster 420 (MM420) indicates that the drive has detected a condition where no load is applied to the inverter. This alarm typically occurs when the drive senses that the motor is not connected or there is an issue with the load. Here’s how to diagnose and address this issue:

1. Check Motor Connections:

   • Ensure that the motor is properly connected to the drive. Check the wiring between the drive and the motor to ensure all connections are secure and correctly wired.

2. Inspect Motor:

   • Verify that the motor is in good working condition. Check for any mechanical issues or damage that might prevent the motor from operating properly.

3. Review Drive Parameters:

   • Verify the drive parameters related to motor control and operation. Key parameters to check include:
     • Motor type
     • Motor voltage
     • Motor current
     • Motor power
   • Ensure that these parameters match the specifications of your motor.

4. Load Conditions:

   • Ensure that there is an actual load connected to the motor. If the motor is running without a load, the drive might interpret this as no load applied to the inverter.
   • Check for mechanical disconnections in the system driven by the motor (e.g., couplings, belts, gearboxes).