You are replacing a three-phase induction motor in an application where equipment could be damaged if the direction of rotation of the motor is incorrect when connected. Assuming that even momentarily jogging the motor could damage equipment and that the feeder phase sequence is ABC clockwise as tested with a phase sequence indicator, what should then be done to ensure that the motor rotation will be correct (clockwise) when connected electrically to the line and mechanically to the load? Assume that the power is off and that the contact-type motor rotation indicator leads are connected to the motor terminals.

Question

Accepted Answer

Rotate the shaft by hand in the clockwise direction as viewed from the drive end. With the push to test pushbutton depressed, if the sequence indicates ABC, phase sequence and motor rotation are in agreement and no connection changes are necessary.

Answer

Rotate the shaft by hand in the clockwise direction as viewed from the drive end. With the push to test pushbutton depressed, if the sequence indicates ACB, phase sequence and motor rotation are NOT in agreement and all three leads must be interchanged.

Answer

Rotate the shaft by hand in the clockwise direction as viewed from the drive end. With the push to test pushbutton depressed, if the sequence indicates ABC, phase sequence and motor rotation are NOT in agreement and any two leads must be interchanged.

Answer

Rotate the shaft by hand in the clockwise direction as viewed from the drive end. With the push to test pushbutton depressed, if the sequence indicates ACB, phase sequence and motor rotation are in agreement and no connection changes are necessary.