Marine Electrical Systems USCG Question #13 (Set 1)

Assuming that the 3-phase power source has a phase sequence of A-B-C and that the motor is connected as shown in figure "A", if the motor has a counterclockwise (CCW) rotation, what statement is true concerning the motors connected as shown in the other figures? Illustration EL-0156

USCG Exam Illustration EL-0156
USCG Examination Diagram: Illustration EL-0156
Official USCG Answer & Rule Citation

Correct Answer: Option B — Motors "B" and "D" would have a clockwise (CW) rotation and motor "C" would have a counterclockwise (CCW) rotation.

In three-phase induction motors, swapping any two of the three supply leads reverses the direction of the rotating magnetic field. Analyzing the phase connections in the provided diagrams reveals that swapping leads results in clockwise rotation for configurations B and D, while C maintains the original counterclockwise rotation.

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