Quiz  /  Electrical Machines Bank PO MCQ Questions With Answers

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

  • Delta Star connected
  • Generally Delta Connected
  • Star Delta Connected
  • Always Star connected

  • 2. 
    A universal motor is one

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

  • 3. 
    The Output frequency of an alternator depends on

  • Type of winding
  • Number of poles and rotational speed
  • Number of poles only
  • Rotational speed only

  • 4. 
    A constant voltage generator has

  • Minimum efficiency
  • Low internal resistance
  • High internal resistance
  • Minimum current capacity

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

  • Universal motor
  • Capacitor start motor
  • Shaded pole motor
  • 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

  • 2.0
  • more than 1
  • 1.0
  • less than 1.

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

  • maximum, voltage
  • maximum, current
  • minimum, voltage
  • minimum, current

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

  • unity
  • 0.8 leading
  • 0.6 leading
  • 0.6 lagging

  • 9. 
    The starting capacitor of a single phase motor is

  • Electrolytic capacitor
  • Ceramic capacitor
  • Paper capacitor
  • 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

  • same
  • more
  • less
  • none of the above

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

  • Demagnetization
  • Cross-Magnetization
  • Zero
  • Operating at high RPM

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

  • Hysteresis motor
  • Shaded pole motor
  • Reluctance motor
  • Two value capacitor motor

  • 13. 
    Synchronous motor works on the principle of

  • Mutual Induction
  • Electromagnetic induction
  • Magnetic locking
  • None of these

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

  • Resistance start method
  • Inductance start method
  • Capacitance start method
  • Split-phase method

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

  • Winding friction
  • Frequency
  • Load
  • Supply Voltage

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

  • Run as before
  • Overheated and eventually burn
  • Not start
  • Burn

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

  • Applied voltage V
  • V2
  • 1/V
  • 1/V2

  • 18. 
    The motor used in household refrigerators is

  • dc series motor
  • dc shunt motor
  • universal motor
  • single phase induction motor

  • 19. 
    The starting torque of a capacitor start motor is

  • zero
  • Low
  • same as rated torque
  • more than rated torque

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

  • Concentrated winding in full pitch coils
  • Concentrated winding in short pitch coils
  • Distributed winding in full pitch coils
  • d) Distributed winding in short pitch coils.

  • 21. 
    How will you find the magnetic flux density?

  • B=ϕ÷AB=\phi\div AB=ϕ÷A
  • E=dϕdtE=\frac{\text{d}\phi}{\text{dt}}E=dtdϕ​
  • H=MMFLH=\frac{MMF}{L}H=LMMF​
  • 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?

  • Active power of machine
  • Reactive power of machine
  • Terminal voltage of machine
  • Frequency of machine

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

  • voltage
  • power
  • current
  • resistance

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

  • Fictitious impedance
  • Fictitious conductance
  • Fictitious resistance
  • Fictitious reactance
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