DC Machine

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Q1:-The efficiency of a motor is generally expressed as 

1. 90 %
2. 75 %
3. 60 %
4. 99 %

ANSWER:-1

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Q2:-The efficiency of a generator is usually expressed as 

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

ANSWER:-3

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Q3:-In swinburne test on a dc machine 

1. all the losses cannot be determined individually
2. copper losses  cannot be determined individually
3. mechanically and iron losses can not be determined individually
4. none of the above

ANSWER:-2

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Q4:-Two  dc machines 500 kw each are tested by Hopkinson test. The power input would be of the order of 

1. 500 kw 
2. 100 kw
3. 1000 kw
4. none of these

ANSWER:-2

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Q5:-The no load voltage of a generator is 230 v and the rated load voltage is 200 v then the voltage regulation

1. 5%
2. 10%
3. 15%
4. 20%

ANSWER:-3

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