Which of these options are correct for a DC electric machine with a large air gap? a) More pulsational loss in pole face b) Quieter operation of the machine c) Distorting effect of armature reaction more d) No proper ventilation

# Which of these options are correct for a DC electric machine with a large air gap? a) More pulsational loss in pole face b) Quieter operation of the machine c) Distorting effect of armature reaction more d) No proper ventilation

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a) Large number of slots

Answer : b

b) Quieter operation of the machine

B. Quiter operation of the machine

A. Large no. Of slots

a) true

b) false

a) chording the stator winding

b) skewing the rotor

c) having a proper slot combination

d) chording the stator winding, skewing the rotor, having a proper slot

combination

a) it helps in improving the efficiency

b) it helps in improving the stopping characteristics

c) it helps in improving the starting characteristics

d) it helps in improving the running characteristics

a) < 2 Hz

b) > 3 Hz

c) < 4 Hz

d) > 3 Hz

a) 2

b) 3

c) 4

d) 5

a) true

b) false

a) additional iron losses = 0.5% of supplied power

b) additional iron losses = 0.6% of supplied power

c) additional iron losses = 0.8% of supplied power

d) additional iron losses = 0.9% of supplied power

a) additional iron losses = 0.5% of supplied power

b) additional iron losses = 0.6% of supplied power

c) additional iron losses = 0.8% of supplied power

d) additional iron losses = 0.9% of supplied power

a) small air gap length, dispersion coefficient increases, good power factor

b) small air gap length, dispersion coefficient decreases, bad power factor

c) small air gap length, dispersion coefficient increases, bad power factor

d) small air gap length, dispersion coefficient decreases, good power factor

a) dispersion coefficient is directly proportional to the power factor

b) dispersion coefficient is indirectly proportional to the power factor

c) dispersion coefficient is directly proportional to the square of the power factor

d) dispersion coefficient is indirectly proportional to the square of the power facto

a) 5

b) 7

c) 10

d) 6

a) overload capacity is directly proportional to the dispersion coefficient

b) overload capacity is indirectly proportional to the dispersion coefficient

c) overload capacity is directly proportional to the square of the dispersion

coefficient

d) overload capacity is indirectly proportional to the square of the dispersion

coefficient

a) overload capacity is directly proportional to the magnetizing current

b) overload capacity is indirectly proportional to the magnetizing current

c) overload capacity is directly proportional to the square of the magnetizing

current

d) overload capacity is indirectly proportional to the square of the magnetizing

current

a) maximum power factor is directly proportional to the number of poles

b) maximum power factor is directly proportional to the square of the number of

poles

c) maximum power factor is indirectly proportional to the number of poles

d) maximum power factor is indirectly proportional to the square of the number of poles

a) true

b) false

a) 4

b) 3

c) 5

d) 2

a) efficiency at full load = output / output + losses

b) efficiency at full load = output / output – losses

c) efficiency at full load = output / output * losses

d) efficiency at full load = output * output + losses

a) 1

b) 4

c) 2

d) 3

a) skin effect

b) mmf harmonics

c) machine design

d) mmf harmonics and skin effect

A. Large no. Of slots

B. Quieter operation of the machine

B. Quiter operation of machine

B.

b) Quieter operation of the machine

b) Quieter operation of the machine

b) Quieter operation of the machine

b) Quieter operation of the machine