Question 209Electricity & Electronics - 1st Asst/Chief

70% to pass

Which of the following statements is true concerning the operation of modern marine electric drive DC propulsion motors?

AThe source and load converters respond to a small reference voltage increasing the frequency applied to the motor until it reaches the desired speed.

BThe cycloconverter is used to increase the voltage applied to the motor until it reaches the desired speed.

CThe rotor follows the frequency and phase sequence rotation of voltage applied to the motor until it reaches the desired speed.

DThe silicon controlled rectifiers in the power converter are used to control the voltage and current applied to the motor armature.

AI Explanation

The correct answer is D) The silicon controlled rectifiers in the power converter are used to control the voltage and current applied to the motor armature. This is correct because in modern marine electric drive DC propulsion motors, the power converter uses silicon controlled rectifiers (SCRs) to control the voltage and current applied to the motor armature, allowing precise speed control. The SCRs regulate the power flow to the motor by modulating the voltage and current, enabling the desired motor speed to be achieved. The other options are incorrect because they do not accurately describe the operation of modern DC propulsion motors. Option A refers to AC motors, option B describes a different type of power converter, and option C describes the behavior of an AC motor's rotor, which is not relevant to DC motors.

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