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) The purpose of the starter is to
A) limit the starting current
B) limit the speed
C) protect against over voltage
D) produce back emf
Ans:A
2) The following starting method for an induction motor is inferior from the point of view of poor starting torque per ampere of the line current drawn
A) Direct-on-line starting
B) Auto transformer method of starting
C) series inductor method of starting
D) Star-delta method of starting
Ans:C
3) Direct-on-line starter can be used for small capacity ................... induction motors
A) squirrel cage
B) wound rotor
C) squirrel cage and wound rotor both types of
Ans:C
4) For starting a small induction motor DOL starter is used in place of iron clad triple-pole (ICTP) switch as it
A) provides protecting against overload and under volt
B) reduces the starting current
C) increases the starting torque
D) improves the power factor and efficiency
Ans:A
5) Induction motors, when directly switched on across their normal rated supply voltage, the torque developed at starting is about ................... of their full load torque.
A) half
B) 1.5 to 2.5 times
C) 5 times
D) 10 times
Ans:B
6) Under which of the following starting methods, an induction motor draws largest starting current?
A) Star-delta starting
B) Auto-transformer starting
C) Direct-on-line starting
D) Reduced voltage starting
Ans:C
7) .................. starter is used for starting a 3-phase induction motor that needs frequent starting and operating in forward and reverse directions
A) Direct-on-line
B) star-delta
C) auto-transformer
D) Reduced voltage
Ans:A
8) The starting current of a 3phase induction motor is 5 times the rated current while the rated slip is 4%. The ratio of starting torque to full-load torque is
A) 0.06
B) 0.8
C) 1.0
D) 1.2
Ans:C
9) With DOL start of an induction motor the heating during acceleration of inertia load is proportional to
A) slip at maximum torque
B) maximum torque
C) stored kinetic energy
D) electromagnetic power developed on the rotor
Ans:D
10) Primary series resistors are employed in the stator for starting a 3-phase squirrel cage induction motor to
A) increase the starting torque
B) improve the pf and efficiency of the motor
C) reduce voltage applied across the motor terminals
D) increase the motor speed
Ans:C
These are some of the objectives of induction machines.. If you like my post share it with your friends and subscribe for latest updates..
1) The purpose of the starter is to
A) limit the starting current
B) limit the speed
C) protect against over voltage
D) produce back emf
Ans:A
2) The following starting method for an induction motor is inferior from the point of view of poor starting torque per ampere of the line current drawn
A) Direct-on-line starting
B) Auto transformer method of starting
C) series inductor method of starting
D) Star-delta method of starting
Ans:C
3) Direct-on-line starter can be used for small capacity ................... induction motors
A) squirrel cage
B) wound rotor
C) squirrel cage and wound rotor both types of
Ans:C
4) For starting a small induction motor DOL starter is used in place of iron clad triple-pole (ICTP) switch as it
A) provides protecting against overload and under volt
B) reduces the starting current
C) increases the starting torque
D) improves the power factor and efficiency
Ans:A
5) Induction motors, when directly switched on across their normal rated supply voltage, the torque developed at starting is about ................... of their full load torque.
A) half
B) 1.5 to 2.5 times
C) 5 times
D) 10 times
Ans:B
6) Under which of the following starting methods, an induction motor draws largest starting current?
A) Star-delta starting
B) Auto-transformer starting
C) Direct-on-line starting
D) Reduced voltage starting
Ans:C
7) .................. starter is used for starting a 3-phase induction motor that needs frequent starting and operating in forward and reverse directions
A) Direct-on-line
B) star-delta
C) auto-transformer
D) Reduced voltage
Ans:A
8) The starting current of a 3phase induction motor is 5 times the rated current while the rated slip is 4%. The ratio of starting torque to full-load torque is
A) 0.06
B) 0.8
C) 1.0
D) 1.2
Ans:C
9) With DOL start of an induction motor the heating during acceleration of inertia load is proportional to
A) slip at maximum torque
B) maximum torque
C) stored kinetic energy
D) electromagnetic power developed on the rotor
Ans:D
10) Primary series resistors are employed in the stator for starting a 3-phase squirrel cage induction motor to
A) increase the starting torque
B) improve the pf and efficiency of the motor
C) reduce voltage applied across the motor terminals
D) increase the motor speed
Ans:C
These are some of the objectives of induction machines.. If you like my post share it with your friends and subscribe for latest updates..
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