Question 235Electricity & Electronics - 1st Asst/Chief

The correct answer is B) interchanging any two of the three line leads to the stator. The reasoning behind this is that in a three-phase induction motor, the direction of rotation is determined by the direction of the rotating magnetic field produced by the stator windings. By interchanging any two of the three line leads, the sequence of the phases is reversed, which in turn reverses the direction of the rotating magnetic field and, consequently, the direction of rotation of the motor. The other options are incorrect because: A) disconnecting one of the three line leads would cause the motor to stop running, not reverse the rotation; C) permanently disconnecting two leads would also cause the motor to stop running; and D) switching the shunt field coil leads is not relevant for a three-phase induction motor, which does not have a shunt field.