Hi friends, this post is about objectives of synchronous machine. Mcq's on synchronous machines which are asked recently in various competitive exams like Gate , Upsc exams and so on. check out and comment if you have any doubts regarding this bits..
1) Larger diameter salient pole rotors have shorter axial length because
A) it occupies much less space
B) it saves lot of copper in stator winding
C) it reduces weight of the rotor
D) number of conductors held in large circumference of rotor is very large and so they need not be long
Ans:D
2) In a salient pole synchronous machine, the airgap is
A) uniform under the whole pole shoe
B) least value the middle of the pole shoe and increases outwards
C) largest under the middle of the pole shoe and decreases outwards
D) least at one end of the pole shoe and increases to the maximum value at the other end
Ans:B
3) The number of poles on turbo-alternator is usually
A) 2
B) 4
C) 6
D) 8
Ans:A
4) To obtain sinusoidal flux distribution. chamfering of poles is done in
A) salient-pole alternators only
B) smooth cylindrical pole alternators only
C) both of the above
D) none of these
Ans:A
5) The salient pole rotors are not suitable for high speed turbo generators due to
A) excessive bearing friction
B) undesirable mechanical oscillations
C) high centrifugal force and windage loss
D) large eddy current losses
Ans:C
6) In turbo-alternators, smooth cylindrical rotors have very long axial length because it
A) reduces friction and windage losses
B) reduces centrifugal force
C) number of conductors being less, they have to be necessarily long for generating the required voltage
D) none of the above
Ans:C
7) Cylindrical rotor alternators use .................. ducts for efficient cooling
A) only radial
B) only axial
C) both radial and axial
D) none of the above
Ans:C
8) In cylindrical rotor ................. portion of rotor is wound
A) one-third
B) two-third
C) one-half
D) whole
Ans:B
9) The maximum possible speed at which an alternator can be driven to generate 50 hz and 4000 V is
A) 4000 rpm
B) 3600 rpm
C) 3000 rpm
D) 1500 rpm
Ans:C
10) Two mechanically coupled alternators deliver power at 50 Hz and 60 Hz respectively. The highest speed of the alternators is
A) 3600 rpm
B) 3000 rpm
C) 600 rpm
D) 500 rpm
Ans:C
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1) Larger diameter salient pole rotors have shorter axial length because
A) it occupies much less space
B) it saves lot of copper in stator winding
C) it reduces weight of the rotor
D) number of conductors held in large circumference of rotor is very large and so they need not be long
Ans:D
2) In a salient pole synchronous machine, the airgap is
A) uniform under the whole pole shoe
B) least value the middle of the pole shoe and increases outwards
C) largest under the middle of the pole shoe and decreases outwards
D) least at one end of the pole shoe and increases to the maximum value at the other end
Ans:B
3) The number of poles on turbo-alternator is usually
A) 2
B) 4
C) 6
D) 8
Ans:A
4) To obtain sinusoidal flux distribution. chamfering of poles is done in
A) salient-pole alternators only
B) smooth cylindrical pole alternators only
C) both of the above
D) none of these
Ans:A
5) The salient pole rotors are not suitable for high speed turbo generators due to
A) excessive bearing friction
B) undesirable mechanical oscillations
C) high centrifugal force and windage loss
D) large eddy current losses
Ans:C
6) In turbo-alternators, smooth cylindrical rotors have very long axial length because it
A) reduces friction and windage losses
B) reduces centrifugal force
C) number of conductors being less, they have to be necessarily long for generating the required voltage
D) none of the above
Ans:C
7) Cylindrical rotor alternators use .................. ducts for efficient cooling
A) only radial
B) only axial
C) both radial and axial
D) none of the above
Ans:C
8) In cylindrical rotor ................. portion of rotor is wound
A) one-third
B) two-third
C) one-half
D) whole
Ans:B
9) The maximum possible speed at which an alternator can be driven to generate 50 hz and 4000 V is
A) 4000 rpm
B) 3600 rpm
C) 3000 rpm
D) 1500 rpm
Ans:C
10) Two mechanically coupled alternators deliver power at 50 Hz and 60 Hz respectively. The highest speed of the alternators is
A) 3600 rpm
B) 3000 rpm
C) 600 rpm
D) 500 rpm
Ans:C
If you like my post please share it with your friends and subscribe to latest updates.. If you have doubts you can start new topic on forum and start discussion with our readers..
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