Losses in the Induction Motor - MCQs with Answers
Q1. If P2 is the rotor input power, Pm is the gross mechanical power developed and s is the slip of induction motor, then the gross mechanical power developed isa. S P
2b. (1-s) P
2c. P
2 / s
d. P
2 / (1-s)
View Answer / Hide AnswerQ2. For sip s of an induction motor, the ratio of rotor copper loss to the gross mechanical output is a. 1 / ( 1 - s)
b. 1 / s
c. ( 1 - s ) / s
d. s / ( 1 - s )
View Answer / Hide AnswerQ3. The torque equation of an induction motor is gives as
ksE22R2 / R22 + (sX2)2
The value of k in the above equation is,a. 3 / (2 Π n
s)
b. 2 / (Π n
s )
c. 2 / (3 Π n
s)
d. 3 / (Π n
s)
View Answer / Hide AnswerQ4. While delivering an useful power of 20 kW to the full load, a 3 phase, 50 Hz, 6 pole induction motor draws a line current of 50 A. it is connected to supply of 420 V and runs at a speed of 950 rpm. If mechanical losses are 1000 W, then its rotor copper losses and shaft torque area. 1105.26 W, 201.03 N-m
b. 1125.26 W, 201.03 N-m
c. 1105.26 W, 208.09 N-m
d. 1125.26 W, 208.09 N-m
View Answer / Hide AnswerANSWER: a. 1105.26 W, 201.03 N-m
a. 42.89 A
b. 45.56 A
c. 47.73 A
d. None of these
View Answer / Hide AnswerQ6. In a three phase induction motor, the mechanical load should be such that the equivalent load resistance referred to stator is equal to thea. Total leakage reactance of the motor referred to stator
b. Total leakage reactance of the motor referred to rotor
c. Total leakage impedance of the motor referred to stator
d. Total leakage impedance of the motor referred to rotor
View Answer / Hide AnswerANSWER: c. Total leakage impedance of the motor referred to stator
a. 60 / (2 Π N
s) N-m
b. (2 Π N
s) / 60 N-m
c. 120 / (2 Π N
s) N-m
d. (2 Π N
s) / 120 N-m
View Answer / Hide AnswerANSWER: a. 60 / (2 Π Ns) N-m
a. Leads the magnetic flux by 90 degree
b. Lags the magnetic flux by 90 degree
c. Lags the magnetic flux by 30 degree
d. In phase with the magnetic flux
View Answer / Hide AnswerANSWER: b. Lags the magnetic flux by 90 degree
