DC Machine

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Q1:-One dc motor drive another dc motor . the second dc motor when excited and driven it 

1. run
2. does not run as generator
3. run as a generator
4. also runs as motor

ANSWER:-3

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Q2:-In dc shunt motor it the terminal voltage is reduced to half and torque remains the same then

1. speed will be half and armature current also will be half
2. speed will be half but armature current remains the same\
3. speed will be half and armature current becomes double 
4. speed and armature current will remains the same.

ANSWER:-3

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Q3:-The armature of dc motors is laminated 

1. to reduced the hysteresis losses
2. to reduced the eddy current losses
3. to reduced the inductivity of armature
4. to reduced the mass of the armature

ANSWER:-2 

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Q4:-The direction of rotation of a dc shunt motor is reversed by 

1. reversing armature connections
2. interchanging the armature and field connection 
3. adding resistance to the field circuit
4. reversing supply connection

ANSWER:-1

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Q5:-The efficiency of any electrical machine /apparatus will be high if

1. its losses are minimum 
2. its losses are more 
3. voltage applied is constant
4. the current drawn is minimum.

ANSWER:-1

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