Armature Of Direct Current Machine Objective Questions and Answers
26. Armature of a DC machine is made of
A. Conducting material
B. Insulating material
C. Non-ferrous material
D. Silicon steel
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D. Silicon steel
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27. The armature of a DC machine is laminated
A. To reduce the hysteresis loss
B. To reduce eddy current loss
C. To reduce the mass
D. To reduce the inductance
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28. The teeth in the armature of a DC machine are sometimes skewed. This is done to reduce
A. Hysteresis loss
B. Copper loss
C. Eddy current loss
D. Vibration
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29. The armature of a DC machine is made of silicon steel laminations to
A. Reduce hysteresis loss only
B. Reduce the eddy current loss only
C. Increase the permeability
D. Reduce both hysteresis and eddy current losses
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30. In a DC machine the armature is always on the rotor unlike an AC machine where it could be either on the stator or rotor , because
A. Commutation action would otherwise not be possible
B. Armature reaction demagnetising action would otherwise be more
C. Otherwise it would not be possible to place compensating winding in pole shoes
D. Self starting of DC motor would not be possible otherwise
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