Direct Current Machine Or DC Machine Objective Questions and Answers


1.  Poles of a DC machine are often laminated to


   A. Reduce pulsation loss

   B. Reduce armature reaction

   C. Reduce iron weight

   D. dissipate more heat


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A. Reduce pulsation loss

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2.  Pole shoe of a DC machine is laminated for the purpose of


   A. Decreasing hysteresis loss

   B. Decreasing eddy current loss

   C. Decreasing both hysteresis and Eddy current losses

   D. None of the above


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B. Decreasing eddy current losses

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3.  in a DC machine


   A. The current and EMF in armature conductors are alternating while those at the terminals are unidirectional

   B. The current and EMF in armature conductors are unidirectional while those at the terminals are alternating

   C. The current and EMF in armature conductors and at the terminals are unidirectional times

   D. The EMF in armature conductors and at the terminals is alternating while current there is unidirectional


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A. The current and EMF in armature conductors are alternating while those at the terminals are unidirectional

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4.  The dummy coils in DC machines are useful to


   A. Increase the efficiency

   B. Improve the commutation

   C. Reduce the cost of the machine

   D. Maintain mechanical balance of armature


✔ View Answer


D. Maintain mechanical balance of armature

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5.  The function of pole shoes in a DC machine is to


   A. Support the field coils

   B. Reduce the reluctance of the magnetic path

   C. Spread out the flux to achieve uniform flux distribution in the air gap

   D. All of the above


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D. All of the above

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