How can a technician check if a three-phase blower motor is rotating in the proper direction?

Starting the motor briefly using the disconnect and verifying proper rotation is the most effective method for troubleshooting a three-phase blower motor. In three-phase systems, the rotation direction is determined by the phase sequence of the power supplied. By briefly energizing the motor, the technician can observe the rotation direction immediately. This is a practical and direct approach to ensuring that the motor is functioning as intended and is critical for applications like HVAC systems, where correct airflow is vital for performance.

Other methods may provide indications or hints about the rotation direction but might not confirm it definitively. For example, checking the slope of the blower vanes can suggest which direction the fan should turn, but it won't guarantee the current operation direction. Similarly, a directional arrow on the blower wheel can offer guidance, yet it is still not definitive proof of the actual rotation at the moment of operation. Observing airflow with a hand could indicate movement but would not accurately confirm whether the motor is rotating in the correct direction, as the air could still flow due to other factors. Therefore, the most reliable approach is to start the motor and observe its rotation directly.