Question 401Electricity/Electronics - Assistant Engineer70% to pass
As shown in the illustration of an electrically operated watertight door controller, what type of motor is used to open and close the watertight door? Illustration EL-0115
AI Explanation
The correct answer is C) Series wound DC motor.
The series wound DC motor is commonly used to operate electrically controlled watertight doors on ships because it provides the necessary torque and speed characteristics required for this application. The series wound configuration allows the motor to develop high starting torque, which is important for opening and closing the heavy watertight doors against water pressure.
The other options are incorrect because: A) Permanent magnet DC motors do not have the same high starting torque capabilities, B) Compound wound DC motors are less suitable for this application, and D) Shunt wound DC motors generally have lower starting torque compared to series wound motors.
Related Questions
#399 Referring to the containership one-line distribution diagram shown in the illustration, what is the purpose of the feedback circuit breaker as used to bypass the automatic bus transfer device? Illustration EL-0014 #400 Referring to the containership one-line distribution diagram shown in the illustration, what is the purpose of the transformers providing power to the refrigerated container feeder bus? Illustration EL-0014 #402 As shown in the illustration of an electrically operated watertight door controller, how is reversal of the direction of motor rotation achieved? Illustration EL-0115 #403 As shown in the illustration of an electrically operated watertight door controller, how is the motor stopped automatically when the door is wedged open? Illustration EL-0115 #404 By what means is the burning of controller contacts due to arcing, when opening, prevented?