Electrical Machines Questions and Answers_pag163

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d) 
View Answer 
Answer: a 
Explanation: The short circuit current will be a constant value till it flows. 
15. A stationary alternator is connected to the infinite bus. It should not be connected because 
a) it will get short circuited 
b) it will operate as induction motor 
c) it will reduce bus bar voltage 
d) all of the mentioned 
View Answer 
Answer: a 
Explanation: When a stationary synchronous machine is connected to the infinite bus, due to 
lack of synchronism there will be short circuit in the machine as the impedance reached very 
negligible. 
16. Which of the options given will have no effect on the working of the synchronous motor if 
ignored? 
a) It has comparable reactance 
b) It requires dc excitation 
c) It can not be started under no load 
d) It has tendency to hunt 
View Answer 
Answer: a 
Explanation: The medium reactance is not any disadvantage to the synchronous machine. 
17. When synchronous motor is running at synchronous speed, the damper winding produces 
a) no torque 
b) eddy current torque 
c) damping torque 
d) torque aiding the developed torque 
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