Question 246Electricity & Electronics - 1st Asst/Chief

The correct answer is C) reversing the phase sequence applied to the AC propulsion motor. In a conventional AC turbo-electric drive system, the main propeller shaft rotation is normally reversed by reversing the phase sequence applied to the AC propulsion motor. This changes the direction of the rotating magnetic field within the motor, which in turn reverses the direction of the propeller shaft rotation. Reversing the field polarity of the AC propulsion motor (option A) or generator (option B) would not achieve the desired reversal of rotation. Option D, reversing the steam turbine direction, is also incorrect as it does not directly impact the propeller shaft rotation in an AC turbo-electric drive system.