Question 577Electricity & Electronics - Assistant Engineer

The correct answer is C) an open in the rotor field circuit. If there is an open in the rotor field circuit of a shipboard AC generator, it will result in a failure to produce any voltage output. The rotor field circuit is responsible for generating the magnetic field that induces the voltage in the stator windings. With an open in this circuit, the rotor cannot produce the necessary magnetic field, and the generator will not be able to generate any voltage. The other answer choices are incorrect because they do not directly relate to a failure to produce voltage. Excessive locked-rotor current (A) would cause the generator to draw too much current, but it would still produce a voltage. A rotating slip ring (B) is not the cause of a voltage failure, and the brushes shifting out of the neutral plane (D) would not necessarily result in a complete loss of voltage.