DC Machine

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Q1:-A shunt generator has a speed of 500 rpm when delivering 100 kw at 200 v. it run as a motor taking an input of 100 kw from 200 v mains the speed will be 

1. 500 rpm
2. less than 500 rpm
3. more than 500 rpm
4. none of these 

ANSWER:-2

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Q2:-Swinburne test can not be used or 

1. series motor
2. shunt motor
3. compound motor
4. none of these

ANSWER:-1

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Q3:-In Hopkinson test on a pair of shunt machines 

1. the armature currents of the motor and generator are equal
2. the armature current of the motor is less than that of generator
3. the armature current of the generator is less than that of the motor 
4. none of these 

ANSWER:-2

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Q4:- In a dc machine the maximum losses occur due to 

1. iron losses
2. mechanical losses
3. copper losses
4. none of these

ANSWER:-3

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Q5:-The efficiency of a motor is generally expressed as

1. (input -losses) / input
2. output / input
3. output / (output+losses)
4. none of the above

ANSWER:-1

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