A synchronous motor operates at 0.8 pf lagging. If the field current of the motor is continuously

A synchronous motor operates at 0.8 pf lagging. If the field current of the motor is continuously increased 

1. The power factor decreases upto a certain value of field current and thereafter it increases. 

2. The armature current increases upto a certain value of field current and thereafter it decreases. 

3. The power factor increases upto a certain value of field current and thereafter it decrease 

4. The armature current decreases upto a certain value of field current and thereafter it, increases.

 From these, the correct answer is (a) 1, 2 (b) 3, 4 (c) 1, 3 (d) 2, 4
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1 Answer

Answer :

A synchronous motor operates at 0.8 pf lagging. If the field current of the motor is continuously increased 

1. The power factor decreases upto a certain value of field current and thereafter it increases. 

2. The armature current increases upto a certain value of field current and thereafter it decreases. 

3. The power factor increases upto a certain value of field current and thereafter it decrease 

4. The armature current decreases upto a certain value of field current and thereafter it, increases.

 From these, the correct answer is (a) 1, 2 (b) 3, 4 (c) 1, 3 (d) 2, 4

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