11) The approximate efficiency of a 3-phase, 50Hz, 4-pole induction motor running at 1350 r.p.m. is ………
a) 90%
b) 40%
c) 65%
d) none of the above
12) For higher efficiency of 3-phase induction motor, the slip should be ……..
a) large
b) very large
c) as small as possible
d) 1
13) In an induction motor, the ratio of rotor Cu loss and rotor input is given by
a) s
b) 1/s
c) 1 – s
d) s/1 – s
14) The no-load speed of an induction motor depends upon
a) the supply frequency
b) the number of its poles
c) the maximum flux/phase
d) only (i) and (ii)
15) The supply voltage to an induction motor is reduced by 1%. By what percentage, approximately, will the maximum torque decrease?
a) 20%
b) 50%
c) 40%
d) 10%
16) In an induction motor, slip depends on
a) supply frequency
b) rotor input power
c) rotor copper loss
d) (ii) and (iii)
17) The operation of an induction motor is based on
a) Lenz’s law
b) Ampere’s law
c) mutual induction
d) self induction
18) The frequency of rotor current in a 6-pole, 50 Hz, 3-phase induction motor running at 950 r.p.m. is
a) 2.5 Hz
b) 1.5 Hz
c) 5 Hz
d) 0.05 Hz
19) If the speed of 3-phase induction motor increases, its efficiency
a) decreases
b) increases
c) remains the same
d) insufficient data
Three Phase Induction Motor MCQ Q-Answer Electrical Engineering All we have given here you can practice on our website if you want.