1. The stator frame in an induction motor is used to
(A) Hold armature stamping in position
(B) Ventilate the armature
(C) protect the whole machine
(D) provide a return path for the flux
Ans: (A) Hold armature stamping in position
2. The frame of an induction motor is made of
(A) aluminum
(B) silicon steel
(C) closed grained cast iron
(D) stainless steel
Ans: (C) closed grained cast iron
3. 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) None of the above
Ans: (A) eddy current loss
4. Use of fractional pitch winding
(A) results in the reduced leakage reactance
(B) result in reduced axial length of the machine
(C) makes it stiffer
(D) all of the above
Ans: (D) all of the above
5. In a 3 phase squirrel cage induction motor
(A) rotor conductors are short-circuited through end rings
(B) rotor conductor ends are short-circuited through a slip ring
(C) rotor conductors are kept open
(D) none of the above
Ans: (A) rotor conductors are short-circuited through end rings
6. The squirrel cage rotor of a 6 pole induction motor can be used for ......... induction motor.
(A) only 6 pole
(B) 6 or 12 pole
(C) any number of poles in an
(D) none of the above
Ans: (C) any number of poles in an
7. The squirrel cage motors are provided with blades in order to
(A) facilitate cooling of the rotor
(B) balance the rotor dynamically
(C) eliminate noise
(D) none of these
Ans: (A) facilitate cooling of the rotor
8. The rotor of a 3 phase wound rotor induction motor is provided with
(A) single-phase winding
(B) three-phase winding
(C) heavy copper or aluminium bars placed in rotor slots
(D) heavy short-circuited end rings
Ans: (B) three-phase winding
9. The rotor winding for 3 phase slip ring induction motor having delta connected stator must be connected in
(A) delta
(B) star
(C) delta or star according to need
(D) none of the above
Ans: (B) star
10. In a 3 phase slip ring induction motor, brushed are connected to
(A) external star connected resistors
(B) Dc supply
(C) 3 phase ac supply
(D) equalizing coils
Ans: (A) external star connected resistors
