302.  Which of the following methods gives the greatest braking torque?
A. Regenerative braking
B. Plugging
C. Rheostatic braking
D. None of the above

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303.  A brake test on D.C. motors restricted to
A. small horse power motors
B. variable speed motors
C. high speed motors
D. open frame type motors.

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304.  In case of D.C. machines, mechanical losses are primary function of
A. current
B. voltage
C. speed
D. none of above

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305.  Iron losses in a D.C. machine are independent of variations in
A. speed
B. load
C. voltage
D. speed and voltage

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306.  In D.C. generator, on no load
A. magnetic neutral axis moves from geometrical neutral axis in the opposite direction of rotation
B. magnetic neutral axis coincides with geometrical neutral axis
C. magnetic neutral axis moves from geometrical neutral axis in the direction of rotation
D. none of the above

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307.  If B is the flux density, / the length of conductor and v the velocity of conductor, then induced e.m.f. is given by
A. B/v
B. B/v2
C. B/2v
D. Bpv2

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308.  For generating large currents on D.C. generators which winding is generally preferred?
A. Progressive wave winding
B. Lap winding
C. Retrogressive wave winding
D. Current depends on design

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