57. A dc generator operates at constant speed, variable load, Which of the following losses is likely to be most significant?
A. windage loss
B. eddy current loss
C. copper loss
D. bearing friction loss

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58. A de simplex lap winding
A. is a completely closed winding
B. has a minimum number of brushes
C. has a number of parallel paths equal to the number of poles
D. has all the above features

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59. In a dc generator, windage loss is proportional to
A. supply voltage
B. square of supply voltage
C. square of armature speed
D. armature speed

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60. Iron losses in a dc machine take place in
A. yoke
B. commutator
C. armature rotor
D. armature conductors

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61.  Hysteresis loss in dc machine is given by?1.6 is IV, where V is
A. the voltage generated
B. peripheral velocity
C. volume of iron part
D. volume of copper conductors

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62.  Core losses in a dc machine occur in
A. armature alone
B. pole faces alone
C. both armature and pole faces
D. yoke alone

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63.  A dc generator has commercial efficiency electrical efficiency tie and mechanical efficiency qm Then
A. Ile =
B. le = nc. Tim
C.#NAME?
D.lm=lc+Tle

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