A.C. Motors Introduction MCQs – CHAPTER 3 DAE 20 min Score: 0 Attempted: 0/20 Subscribe 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 energyShow All Answers 2. Motors which operate on AC supply are called; (A) AC motors (B) DC motors (C) Synchronous motors only (D) Universal motors onlyShow All Answers 3. Single-phase AC motors are commonly used in; (A) Large industrial plants (B) Heavy machinery (C) Homes, offices, schools, and shops (D) Power plantsShow All Answers 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 motorsShow All Answers 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 rotorShow All Answers 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 disconnectedShow All Answers 7. Single-phase motors are converted to two-phase motors to; (A) Reduce size (B) Reduce cost (C) Make them self-starting (D) Increase efficiencyShow All Answers 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 obtainedShow All Answers 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 maintenanceShow All Answers 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 theseShow All Answers 11. Single-phase induction motors include; (A) Split Phase Motor (B) All of the above (C) Shaded Pole Motor (D) Capacitor type MotorShow All Answers 12. Commutator motors in single-phase include; (A) Repulsion Motor (B) A.C. Series Motor (C) All of the above (D) Universal MotorShow All Answers 13. Classification of motors according to type of current includes; (A) Single-phase (B) All of the above (C) Two-phase (obsolete) (D) Three-phaseShow All Answers 14. According to speed, AC motors can be; (A) All of the above (B) Variable speed (C) Adjustable speed (D) Constant speedShow All Answers 15. According to structural features, AC motors can be; (A) Open type (B) Enclosed type (C) Semi-enclosed type (D) All of the aboveShow All Answers 16. Shaded pole motors are generally; (A) Single-phase motors (B) Three-phase motors (C) DC motors (D) Commutator motorsShow All Answers 17. Fractional horse power motors are usually; (A) Low in power rating (B) Expensive (C) High in voltage rating (D) Multi-phase motorsShow All Answers 18. AC motors can improve; (A) Efficiency only (B) Power factor (C) Only torque (D) Speed onlyShow All Answers 19. The universal motor belongs to; (A) Single-phase commutator motors (B) Synchronous motors (C) Three-phase induction motors (D) Shaded pole motorsShow All Answers 20. Split-phase motors are a type of; (A) Synchronous motors (B) Single-phase induction motors (C) Three-phase induction motors (D) Commutator motorsShow All Answers
