| As shown in the illustration of a turbo-electric propulsion drive system, in terms of motor speed and direction control, what statement is true? |
| A) the motor speed is controlled by varying voltage and frequency and the direction is controlled by reversing the polarity of the motor field |
| B) the motor speed is controlled by varying voltage, but keeping the frequency constant and the direction is controlled by phase sequence reversal |
| C) the motor speed is controlled by varying frequency, but keeping the voltage constant and the direction is controlled by phase sequence reversal |
| D) the motor speed is controlled by varying voltage and frequency and the direction is controlled by phase sequence reversal |
