Motor stall

What does A780 mean?

This is a programmable warning indicating a motor stall condition. The motor current has exceeded the defined stall current limit, while the output frequency or speed is below its respective limit for a set duration. This suggests the motor is overloaded or mechanically constrained, potentially leading to overheating if not addressed.

• Mechanical overload on the driven equipment (e.g., jammed conveyor, seized bearing in load) exceeding the motor's torque capability.
• Incorrectly set motor stall protection parameters (e.g., P30.01 Motor stall current too low, P30.02 Stall time too short).
• Insufficient motor torque for the application's demand, possibly due to undersized motor or incorrect motor parameters (P99.04 Motor nominal current).
• Severe voltage sag on the input supply leading to reduced motor torque output.
• Excessive friction in mechanical transmission (e.g., gearbox, belt drive) preventing motor acceleration.

Click steps to track your progress.

1. 1

   Examine the mechanical load for obstructions, excessive friction, or jams; clear any identified blockages.

2. 2

   Review drive parameter P30.01 (Motor stall current limit) and P30.02 (Motor stall time) against the motor's actual locked rotor current and application requirements.

3. 3

   Measure the actual motor current (e.g., via parameter P01.03) during operation and compare it to the motor's nominal current on its nameplate.

4. 4

   Verify motor parameters (e.g., P99.04 Motor nominal current, P99.05 Motor nominal speed) are accurately entered into the drive.

5. 5

   Monitor the input line voltage (e.g., via parameter P06.01) for sags during acceleration or high load conditions.