Important Electrical Machine Design Multiple Choice Questions and Answers
26. The Polo shoes of a DC machines
A. Are always laminated
B. Are never laminated
C. Are sometimes laminated
D. Are partially laminated
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A. Are always laminated
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27. Poles of DC machines are often laminated to
A. Reduce pulsation loss
B. Reduce armature reaction
C.Reduce iron weight
D. Dissipate more heat
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28. In DC machines the increase in field MMF causes
A. Increase in size and cost of the machine
B. Reduction in size and cost of the machine
C. Excessive sparking
D. None of the above
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29. The yoke of a DC machine
A. Mast to be made of magnetic material
B. Should preferably be made of magnetic material but can be of non-magnetic material
C. Must be made of non-magnetic material
D. Is partially made of magnetic material and partially of non-magnetic material
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30. Use of more number of poles in a DC machine reduces
A. Wait of course and yoke
B. Cost of copper in armature as well as field
C. Overall diameter and length of the machine
D. All of the above
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