Electrical Machines Bank PO MCQ Questions With Answers Quiz Questions

1. The a.c. the armature winding of an alternator is

A Delta Star connected B Generally Delta Connected C Star Delta Connected D Always Star connected

2. A universal motor is one

A which can run on any value of supply voltage B which has infinitely varying speed C which can operate on ac as well as dc voltage D which can work as single phase or three phase motor.

3. The Output frequency of an alternator depends on

A Type of winding B Number of poles and rotational speed C Number of poles only D Rotational speed only

4. A constant voltage generator has

A Minimum efficiency B Low internal resistance C High internal resistance D Minimum current capacity

5. Out of the following motors, which will give the highest starting torque

A Universal motor B Capacitor start motor C Shaded pole motor D All have zero starting torque.

6. In a split phase motor, the ratio of number of turns for starting winding to that for running winding is

A 2.0 B more than 1 C 1.0 D less than 1.

7. Current rating is the _____ continuous _____ that an equipment will carry indefinitely without undue deterioration to the equipment.

A maximum, voltage B maximum, current C minimum, voltage D minimum, current

8. A capacitor start single phase induction motor will usually have a power factor of

A unity B 0.8 leading C 0.6 leading D 0.6 lagging

9. The starting capacitor of a single phase motor is

A Electrolytic capacitor B Ceramic capacitor C Paper capacitor D None of the above.

10. The number of turns in the starting winding of a capacitor start motor as compared to that for split phase motor is

A same B more C less D none of the above

11. When the power factor of an alternator is unity then the armature flux will be

A Demagnetization B Cross-Magnetization C Zero D Operating at high RPM

12. Which single phase ac motor will you select for record players and tape recorders ?

A Hysteresis motor B Shaded pole motor C Reluctance motor D Two value capacitor motor

13. Synchronous motor works on the principle of

A Mutual Induction B Electromagnetic induction C Magnetic locking D None of these

14. Which of the following is the most economical method of starting a single phase motor

A Resistance start method B Inductance start method C Capacitance start method D Split-phase method

15. In a Synchronous motor, ”Hunting” may be due to variation in any of the followingEXCEPT

A Winding friction B Frequency C Load D Supply Voltage

16. In 3-Phase Synchronous motor if one of the phases is short circuited the motor will

A Run as before B Overheated and eventually burn C Not start D Burn

17. For a Synchronous motor, the breakdown torque will be proportional to

A Applied voltage V B V2 C 1/V D 1/V2

18. The motor used in household refrigerators is

A dc series motor B dc shunt motor C universal motor D single phase induction motor

19. The starting torque of a capacitor start motor is

A zero B Low C same as rated torque D more than rated torque

20. In Synchronous Generator, which of the following coils will have emf closer to sine wave form?

A Concentrated winding in full pitch coils B Concentrated winding in short pitch coils C Distributed winding in full pitch coils D d) Distributed winding in short pitch coils.

21. How will you find the magnetic flux density?

A B=ϕ÷AB=\phi\div AB=ϕ÷A B E=dϕdtE=\frac{\text{d}\phi}{\text{dt}}E=dtdϕ C H=MMFLH=\frac{MMF}{L}H=LMMF D MMM=NIMMM=NIMMM=NI

22. If the excitation of a 3-Phase alternator operating on infinite bus bars is changed, which of the following shall alter?

A Active power of machine B Reactive power of machine C Terminal voltage of machine D Frequency of machine

23. Fuse is designed to break the _____ flowing through the circuit.

A voltage B power C current D resistance

24. In an alternator, armature reaction is considered equivalent to

A Fictitious impedance B Fictitious conductance C Fictitious resistance D Fictitious reactance