1. An electric motor is a machine that converts;
(A) Electrical energy into mechanical energy
(B) Mechanical energy into electrical energy
(C) Thermal energy into electrical energy
(D) Chemical energy into mechanical energy
2. Motors which operate on AC supply are called;
(A) AC motors
(B) DC motors
(C) Synchronous motors only
(D) Universal motors only
3. Single-phase AC motors are commonly used in;
(A) Large industrial plants
(B) Heavy machinery
(C) Homes, offices, schools, and shops
(D) Power plants
4. Single-phase motors with very low power rating are called;
(A) Three-phase motors
(B) Commutator motors
(C) Universal motors
(D) Fractional horse power motors
5. Single-phase motors cannot start automatically because;
(A) No flux is produced in stator
(B) They have no rotor
(C) AC supply is insufficient
(D) Two equal and opposite torques are produced in rotor
6. The motor can start when;
(A) An external starting torque is applied
(B) Single winding is used
(C) The motor is cooled
(D) Rotor is disconnected
7. Single-phase motors are converted to two-phase motors to;
(A) Reduce size
(B) Reduce cost
(C) Make them self-starting
(D) Increase efficiency
8. AC motors are preferred over DC motors because;
(A) They are robust and durable
(B) They are low in cost and require less maintenance
(C) All of the above
(D) Different torque/speed characteristics can be obtained
9. AC motors have an advantage over DC motors in that;
(A) Auxiliary and protective devices are expensive
(B) They cannot operate at variable speeds
(C) They have high thermal stability
(D) They require more maintenance
10. According to the principle of operation, a synchronous motor can be;
(A) Both A and B
(B) Un-excited (Single Phase)
(C) Excited (Three phase)
(D) None of these
11. Single-phase induction motors include;
(A) Split Phase Motor
(B) All of the above
(C) Shaded Pole Motor
(D) Capacitor type Motor
12. Commutator motors in single-phase include;
(A) Repulsion Motor
(B) A.C. Series Motor
(C) All of the above
(D) Universal Motor
13. Classification of motors according to type of current includes;
(A) Single-phase
(B) All of the above
(C) Two-phase (obsolete)
(D) Three-phase
14. According to speed, AC motors can be;
(A) All of the above
(B) Variable speed
(C) Adjustable speed
(D) Constant speed
15. According to structural features, AC motors can be;
(A) Open type
(B) Enclosed type
(C) Semi-enclosed type
(D) All of the above
16. Shaded pole motors are generally;
(A) Single-phase motors
(B) Three-phase motors
(C) DC motors
(D) Commutator motors
17. Fractional horse power motors are usually;
(A) Low in power rating
(B) Expensive
(C) High in voltage rating
(D) Multi-phase motors
18. AC motors can improve;
(A) Efficiency only
(B) Power factor
(C) Only torque
(D) Speed only
19. The universal motor belongs to;
(A) Single-phase commutator motors
(B) Synchronous motors
(C) Three-phase induction motors
(D) Shaded pole motors
20. Split-phase motors are a type of;
(A) Synchronous motors
(B) Single-phase induction motors
(C) Three-phase induction motors
(D) Commutator motors