HAL Questions

HAL TYPICAL QUESTIONS & ANSWERS OBJECTIVE TYPE QUESTIONS ,HAL electronics and electrical questions and answers,

Q.1 The two windings of a transformer is 
(A) conductively linked. 
(B) inductively linked. 
(C) not linked at all. 
(D) electrically linked. 
Ans : B 

Q.2 A salient pole synchronous motor is running at no load. Its field current is switched off. The motor will 
(A) come to stop. 
(B) continue to run at synchronous speed.
(C) continue to run at a speed slightly more than the synchronous speed. 
(D) continue to run at a speed slightly less than the synchronous speed. 
Ans: B

Q.3 The d.c. series motor should always be started with load because 
(A) at no load, it will rotate at dangerously high speed. 
(B) it will fail to start. 
(C) it will not develop high starting torque. 
(D) all are true. 
Ans: A 

Q.4 The frequency of the rotor current in a 3 phase 50 Hz, 4 pole induction motor at full 
load speed is about 
(A) 50 Hz. 
(B) 20 Hz. 
(C) 2 Hz. 
(D) Zero.
Ans: C 

Q.5 In a stepper motor the angular displacement 
(A) can be precisely controlled. 
(B) it cannot be readily interfaced with micro computer based controller.
(C) the angular displacement cannot be precisely controlled. 
(D) it cannot be used for positioning of work tables and tools in NC machines. 
Ans: A 

Q.6 The power factor of a squirrel cage induction motor is 
(A) low at light load only. 
(B) low at heavy load only. 
(C) low at light and heavy load both. 
(D) low at rated load only. 
Ans: