Power Generator

131. The mechanical power developed in a dc motor is maximum when back emf is equal to the ___________ applied voltage

1. twice
2. one third
3. one half
4. one fourth

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132. The most commonly used method of speed control of a dc motor is by vbarying

1. voltage applied to the motor
2. felids strength
3. effective number of conductors in series
4. armature circuit resistance

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133. The nature of armature winding of a dc machine is decided by

1. front pitch
2. back pitch
3. commutator path
4. number of coils

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134. The number of cycles generated in a 6 pole alternator in one revolution is

1. 3
2. 5
3. 6
4. 2

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135. The number of parallel paths in a simplex lap winding is equal to

1. 2
2. number of poles
3. number of pair poles
4. 1

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136. The open circuit test on a transformer gives

1. copper losses
2. iron losses
3. friction losses
4. total losses

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137. The open circuit test on a transformer is always made on

1. low voltage winding
2. high voltage winding
3. either low or high voltage
4. neither low or high voltage

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138. the primary leakage flux links

1. primary winding only
2. secondary winding only
3. both primary and secondary windings
4. neither primary nor secondary windings

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139. The rating of an alternator is expressed in

1. kW
2. kVA
3. HP
4. KVAR

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140. The real working Part of a dc machine is the

1. commutator
2. armature winding
3. field winding
4. stator

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