1) An induction motor works with
A) dc only
B) ac only
C) ac and dc only
D) none of these
Ans:B
2) The frame of induction motor is made of
A) aluminium
B) silicon steel
C) closed grained cast iron
D) stainless steel
E) bronze
Ans:C
3) The induction motor shaft should be
A) hollow
B) stiff
C) flexible
D) any of these
Ans:B
4) The stator frame in an induction motor is used to
A) hold the armature stampings in position
B) ventilate the armature
C) protect the whole machine
D) provide return path for the flux
Ans:A
5) Use of fractional pitch winding
A) results in reduced leakage reactance
B) results in reduced axial length of the machine
C) makes it stiffer
D) all of the above
Ans:D
6) The induction motor shaft is made of
A) mild steel
B) cast iron
C) high speed steel
D) stainless steel
E) aluminium
Ans:A
7) Uneven gap in an induction motor is likely to cause
A) heating of motor
B) unbalancing of motor shaft
C) both (a) and (b)
D) none of these
Ans:C
8) In a 3-phase squirrel cage induction motor
A) rotor conductors are short circuited through end rings
B) rotor conductors ends are short circuited through slip rings
C) rotor conductors are kept open
D) none of the above
Ans:A
9) The stator core of a 3-phase induction motor is laminated in order to reduce the
A) eddy current loss
B) hysteresis loss
C) both eddy current and hysteresis loss
D) weight of the stator
E) windage and frictional losses
Ans:A
10) If all the stator coils of an induction motor are connected for the same magnetic polarity, there will be formed an equal number of
A) rotor poles with same polarity
B) rotor poles with opposite polarity
C) consequent poles with opposite polarity
D) consequent poles with same polarity
Ans:C
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