239. The losses occurring in a D.C. generator are given below. Which loss is likely to have the least proportion?
A. Magnetic losses
B. Armature copper losses
C. Mechanical losses
D. Field copper losses

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240. The hysteresis loss in a D.C. machine least depends on
A. Frequency of magnetic reversals
B. Maximum value of flux density
C. Volume and grade of iron
D. Rate of flow of ventilating air

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241. In a D.C. generator all of the following could be the effects of iron losses except
A. Loss of efficiency
B. Excessive heating of core
C. Increase in terminal voltage
D. Rise in temperature of ventilating air

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242. The losses occurring in a D.C. generator are given below. Which loss is likely to have highest proportion at rated load of the generator?
A. hysteresis loss
B. field copper loss
C. armature copper loss
D. eddy current loss

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243. If 't' be the thickness of the laminations, then eddy current loss in a generator will vary as
A. ?
B. t`
C. t
D. t2

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244. Which of the following loss in a is equal to the applied more than the
A.(b) commutator
B.
C. armature conductors
D. armature rotor

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245. If Bmax is the maximum flux density, then eddy current loss will vary as
A. Bmax
B. (Bmax)2
C. (Bmax)"
D. (Bmax)2?4

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