Hi friends, this post is about induction motor objectives. These are some of the questions asked in previous question papers of Gate, IES and other competitive exams. check out and comment if you have any doubts....
1) In a 3-phase induction motor, the number of slots on stator is not kept exact multiple of the number of rotor slots because it
A) facilitates cooling
B) avoids magnetic locking between stator field and rotor
C) improves efficiency
D) improves pf
Ans:B
2) The difference between the number of stator slots and that of rotor slots in an induction motor should not be equal to p, 2p, or 5p. It is essential in order to avoid
A) synchronous cusps
B) crawling
C) magnetic locking
D) noise and vibrations
Ans:A
3) In induction machines, it is usually a standard practice to employ
A) integral slot winding with full pitch coils
B) integral slot winding with chorded coils
C) fractional slot winding with fractional pitch coils
D) fractional slot winding with full pitch coils
Ans:B
4) The rotor slots in a 3-phase induction motor are kept inclined. This phenomenon is known as
A) skewing
B) crawling
C) cogging
D) none of these
Ans:A
5) In an induction motor, skewing of rotor bars reduces
A) eddy currents and copper requirements
B) noise, vibrations and synchronous cusps
C) both (a) and (b)
D) none of these
Ans:B
6) Jogging of an induction motor is
A) energizing a motor once or repeatedly to have small movements for mechanisms
B) a process of synchronisation
C) a method of braking
D) none of the above
Ans:A
7) In 3-phase induction motors, sometimes copper bars are placed deep in the rotor. It is done in order to improve
A) efficiency
B) starting torque
C) power factor
D) none of these
Ans:B
8) In a squirrel cage induction motor high starting torque is achieved by using
A) high resistance in series with the rotor circuit
B) low resistance across the rotor circuit
C) double cage rotor
D) none of these
Ans:C
9) The outer cage of a double squirrel rotor consists of
A) manganese brass
B) red copper
C) bronze
D) steel
Ans:A
10) In double cage induction motor the inner cage has
A) high resistance and high leakage reactance
B) high resistance and low leakage reactance
C) low resistance and high leakage reactance
D) low resistance and low leakage reactance
Ans:C
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1) In a 3-phase induction motor, the number of slots on stator is not kept exact multiple of the number of rotor slots because it
A) facilitates cooling
B) avoids magnetic locking between stator field and rotor
C) improves efficiency
D) improves pf
Ans:B
2) The difference between the number of stator slots and that of rotor slots in an induction motor should not be equal to p, 2p, or 5p. It is essential in order to avoid
A) synchronous cusps
B) crawling
C) magnetic locking
D) noise and vibrations
Ans:A
3) In induction machines, it is usually a standard practice to employ
A) integral slot winding with full pitch coils
B) integral slot winding with chorded coils
C) fractional slot winding with fractional pitch coils
D) fractional slot winding with full pitch coils
Ans:B
4) The rotor slots in a 3-phase induction motor are kept inclined. This phenomenon is known as
A) skewing
B) crawling
C) cogging
D) none of these
Ans:A
5) In an induction motor, skewing of rotor bars reduces
A) eddy currents and copper requirements
B) noise, vibrations and synchronous cusps
C) both (a) and (b)
D) none of these
Ans:B
6) Jogging of an induction motor is
A) energizing a motor once or repeatedly to have small movements for mechanisms
B) a process of synchronisation
C) a method of braking
D) none of the above
Ans:A
7) In 3-phase induction motors, sometimes copper bars are placed deep in the rotor. It is done in order to improve
A) efficiency
B) starting torque
C) power factor
D) none of these
Ans:B
8) In a squirrel cage induction motor high starting torque is achieved by using
A) high resistance in series with the rotor circuit
B) low resistance across the rotor circuit
C) double cage rotor
D) none of these
Ans:C
9) The outer cage of a double squirrel rotor consists of
A) manganese brass
B) red copper
C) bronze
D) steel
Ans:A
10) In double cage induction motor the inner cage has
A) high resistance and high leakage reactance
B) high resistance and low leakage reactance
C) low resistance and high leakage reactance
D) low resistance and low leakage reactance
Ans:C
If you like my post share it with your friends and subscribe for latest updates..
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