| Refer to the simplified diagram of the AC synchronous electric motor drive system as shown in the illustration. The propulsion motor operates from maneuvering speed to full ahead speed in the ahead direction. The propulsion motor will not operate at any speed in the astern direction. What is most likely the problem? Illustration EL-0155 |
| A) The AC propulsion motor field winding fails to reverse in polarity. |
| B) The power supply to the controlled rectifier fails to achieve a phase sequence reversal. |
| C) The AC propulsion motor has an open astern winding. |
| D) The output of the controlled inverter fails to achieve a reversal in phase sequence. |
