MCQ in AC Motors Part 2 | REE Board Exam

(Last Updated On: July 28, 2020)

MCQ in AC Motors Part 2 | REE Board Exam

This is the Multiple Choice Questions Part 2 of the Series in AC Motors as one of the Electrical Engineering topic. In Preparation for the REE Board Exam make sure to expose yourself and familiarize in each and every questions compiled here taken from various sources including but not limited to past Board Exam Questions in Electrical Engineering field, Electrical Engineering Books, Journals and other Electrical Engineering References.

Continue Practice Exam Test Questions Part 2 of the Series

Choose the letter of the best answer in each questions.

MCQ in AC Motors Part 1 | REE Board Exam

51.  EE Board Exam October 1990

Repeated starting and stopping of a motor is referred to as

A.  stepping

B.  jogging

C.  phasing

D.  none of these

View Answer:

Answer: Option B

Solution:

52.  EE Board Exam June 1990

An induction motor driven above synchronous speed is called

A.  induction regulator

B.  frequency changer

C.  induction generator

D.  phase converter

View Answer:

Answer: Option C

Solution:

Unsolved problems

53.  REE Board Exam September 2004

In an induction motor, what is the percent slip if the speed is 3,510?

A.  1

B.  1.5

C.  2

D.  2.5

54.  REE Board Exam September 2002

The speed of an induction motor is 1170 rpm. What is the frequency of the rotor current?

A.  2.5 Hz

B.  37.5 Hz

C.  1.5 Hz

D.  3.3 Hz

55.  REE Board Exam September 2002

A 3-phase, 220 volt induction motor having a power factor of 0.8 has 3% losses. Determine the current drawn by the motor.

A.  25.23 A

B.  43.69 A

C.  20.18 A

D.  14.56 A

56.  REE Board Exam April 2002

A three-phase squirrel cage motor is started by wye-delta starter. What shall be its starting torque relative to its rated voltage starting torque?

A.  33.3%

B.  42.3%

C.  57.7%

D.  100%

57.  ECE Board Exam November 1999

How do you call the speed of an alternating current (AC) induction motor?

A.  Varying supply frequency

B.  Varying series resistance of the field

C.  Varying supply voltage

D.  Varying both the supply voltage and frequency at the same time

View Answer:

Answer: Option D

Solution:

58.  ECE Board Exam November 1995

The best way to control the speed of an AC induction motor is by varying the _____.

A.  supply frequency

B.  both supply voltage and frequency simultaneously

C.  supply voltage

D.  series resistance of the field

View Answer:

Answer: Option B

Solution:

59.  ECE Board Exam November 1997

A two pole, three phase motor has _____ field poles.

A.  6

B.  8

C.  2

D.  4

View Answer:

Answer: Option C

Solution:

60.  ECE Board Exam November 2001

_____ refers to an AC generator.

A.  Commutator

B.  Motor (AC)

C.  Rotor

D.  Alternator

View Answer:

Answer: Option D

Solution:

61.  ECE Board Exam November 2000

Series motors operated on either AC or DC are sometimes called _____.

A.  Universal motors

B.  General motors

C.  Bavarian motors

D.  Anglo motors

View Answer:

Answer: Option A

Solution:

62.  ECE Board Exam April 2001

What does the term single-phase indicate?

A.  One input

B.  One current (one input)

C.  One time

D.  One voltage (one input)

View Answer:

Answer: Option A

Solution:

63.  ECE Board Exam November 1996

Kind of AC-motor, light load high load low speed.

A.  Synchronous motor

B.  Squirrel cage motor

C.  Split phase motor

D.  Universal motor

View Answer:

Answer: Option D

Solution:

64.  ECE Board Exam November 1996

A two pole, one phase motor has _____ field poles.

A.  8

B.  2

C.  6

D.  4

View Answer:

Answer: Option B

Solution:

65.  What is the percent slip of a 4-pole induction motor if the output speed is 1,755 rpm?

A.  3

B.  5

C.  2.5

D.  4

View Answer:

Answer: Option C

Solution:

66.  Regarding skewing of motor bars in a squirrelcage induction motor, (SCIM) which statement is false.

A.  it prevents cogging

B.  it increases starting torque

C.  it produces more uniform torque

D.  it reduces motor ‘hum’ during its operation

View Answer:

Answer: Option B

Solution:

67.  The principle of operation of a 3-phase induction motor is most similar to that of a

A.  synchronous motor

B.  repulsion-start induction motor

C.  transformer with a shorted secondary

D.  capacitor-start, induction-run motor

View Answer:

Answer: Option C

Solution:

68.  The magnetizing current drawn by transformers and induction motors is the cause of their ____ power factor.

A.  zero

B.  unity

C.  lagging

D.  leading

View Answer:

Answer: Option A

Solution:

69.  The effect of increasing the length of air-gap in an induction motor will be to increase the

A.  power factor

B.  speed

C.  magnetizing current

D.  air-gap flux

View Answer:

Answer: Option C

Solution:

70.  In a 3-phase induction motor, the relative speed of stator flux with respect to ____ is zero.

A.  stator winding

B.  rotor

C.  rotor flux

D.  space

View Answer:

Answer: Option A

Solution:

71.  An eight pole wound rotor induction motor operating on 60 Hz supply is driven at 1800 r.p.m. by a prime mover in the opposite direction of revolving magnetic field. The frequency of rotor current is

A.  60 Hz

B.  120 Hz

C.  180 Hz

D.  none of these

View Answer:

Answer: Option C

Solution:

72.  A 3-phase 4 pole, 50 Hz induction motor runs at a speed of 1440 r.p.m. The rotating field produced by the rotor rotates at a speed of _____ r.p.m. with respect to the rotor.

A.  1500

B.  1440

C.  60

D.  0

View Answer:

Answer: Option C

Solution:

73.  In a 3- induction motor, the rotor field rotates at synchronous speed with respect to

A.  stator

B.  rotor

C.  stator flux

D.  none of these

View Answer:

Answer: Option B

Solution:

74.  Irrespective of the supply frequency, the torque developed by a SCIM is the same whenever ____ is the same.

A.  supply voltage

B.  external load

C.  rotor resistance

D.  slip speed

View Answer:

Answer: Option D

Solution:

75.  The number of stator poles produced in the rotating magnetic field of a 3-Ф induction motor having 3 slots per pole per phase is

A.  3

B.  6

C.  2

D.  12

View Answer:

Answer: Option B

Solution:

76.  The power factor of a squirrel-cage induction motor is

A.  low at light loads only

B.  low at heavy loads only

C.  low at light and heavy loads only

D.  low at rated load only

View Answer:

Answer: Option A

Solution:

77.  Which of the following rotor quantity in a SCIM does NOT depend on its slip?

A.  reactance

B.  speed

C.  induced emf

D.  frequency

View Answer:

Answer: Option B

Solution:

78.  A 6-pole, 50-Hz, 3- induction motor is running at 950 rpm and has rotor Cu loss of 5 kW. Its rotor input is ____ kW.

A.  100

B.  10

C.  95

D.  5.3

View Answer:

Answer: Option A

Solution:

79.  The efficiency of a 3-phase induction motor is approximately proportional to

A.  (1 – s)

B.  s

C.  N

D.  Ns

View Answer:

Answer: Option A

Solution:

80.  A 6-pole, 50-Hz, 3- induction has a full-load speed of 950 rpm. At half load, its speed would be ____ rpm.

A.  475

B.  500

C.  975

D.  1000

View Answer:

Answer: Option C

Solution:

81.  If rotor input of a SCIM running with a slip of 10% is 100 kW, gross power developed by its rotor is ____ kW.

A.  10

B.  90

C.  99

D.  80

View Answer:

Answer: Option B

Solution:

82.  Pull-out torque of a SCIM occurs at that value of slip where rotor power factor equals

A.  unity

B.  0.707

C.  0.866

D.  0.5

View Answer:

Answer: Option B

Solution:

83.  When applied rated voltage per phase is reduced by one-half, the starting torque of a SCIM becomes ____ of the starting torque with full voltage.

A.  ½

B.  ¼

C. 1/8

D. ¾

View Answer:

Answer: Option B

Solution:

84.  If maximum torque of an induction motor is 200 kg-m at a slip of 12%, the torque at 6% slip would be ____ kg-m.

A.  100

B.  160

C.  50

D.  40

View Answer:

Answer: Option B

Solution:

85.  The fractional slip of an induction motor is the ratio

A.  rotor Cu loss/rotor input

B.  stator Cu loss/stator input

C.  rotor Cu loss/rotor output

D.  rotor Cu loss/stator Cu loss

View Answer:

Answer: Option A

Solution:

86.  The torque developed by a 3-phase induction motor depends on the following three factors:

A.  speed, frequency, number of poles

B.  voltage, current and stator impedance

C.  synchronous speed, rotor speed and frequency

D.  rotor emf, rotor current and rotor p.f.

View Answer:

Answer: Option D

Solution:

87.  If the stator voltage and frequency of an induction motor are reduced proportionately, its

A.  locked rotor current is reduced

B.  torque developed is increased

C.  magnetizing current is decreased

D.  both A and B

View Answer:

Answer: Option D

Solution:

88.  The efficiency and p.f. of a SCIM increases in proportion to its

A.  speed

B.  mechanical load

C.  voltage

D.  rotor torque

View Answer:

Answer: Option B

Solution:

89.  A SCIM runs at constant speed only so long as

A.  torque developed by it remains constant

B.  its supply voltage remains constant

C.  its torque exactly equals the mechanical load

D.  stator flux remains constant

View Answer:

Answer: Option C

Solution:

90.  The synchronous sped of a linear induction motor does NOT depend on

A.  width of pole pitch

B.  number of poles

C.  supply frequency

D.  any of these

View Answer:

Answer: Option B

Solution:

91.  Thrust developed by a linear induction motor depends on

A.  synchronous speed

B.  rotor input

C.  number of poles

D.  both A and B

View Answer:

Answer: Option D

Solution:

92.  The stator of a 3-phase induction motor produces ____ magnetic field.

A.  steady

B.  rotating

C.  alternating

D.  none of these

View Answer:

Answer: Option B

Solution:

93.  An induction motor is preferred to a dc motor because it

A.  provides high starting torque

B.  provides fine speed control

C.  has simple and rugged construction

D.  none of these

View Answer:

Answer: Option C

Solution:

94.  A 3-phase induction motor is

A.  essentially a constant speed motor

B.  a variable speed motor

C.  very costly

D.  not easily maintainable

View Answer:

Answer: Option A

Solution:

95.  The air gap between stator and rotor of a 3-phase induction motor ranges from

A.  2 cm to 4 cm

B.  0.4 mm to 4 mm

C.  1 cm to 2 cm

D.  4 cm to 6 cm

View Answer:

Answer: Option B

Solution:

96.  If the frequency of 3-phase supply to the stator of a 3-phase induction motor is increased, the synchronous speed

A.  is decreased

B.  is increased

C.  remains unchanged

D.  none of these

View Answer:

Answer: Option B

Solution:

97.  If Ns is the speed of rotating flux and Nr the speed of the rotor, then the rate at which the flux cuts the rotor conductors is directly proportional to

A.  N

B.  N

C.  Ns – Nr

D.  Nr – Ns

View Answer:

Answer: Option C

Solution:

98.  In a 3-phase induction motor, the rotor speed is ____ the synchronous speed.

A.  greater than

B.  smaller than

C.  equal to

D.  none of these

View Answer:

Answer: Option B

Solution:

99.  The synchronous speed of a 3-phase induction motor having 20 poles and connected to a 50 Hz source is

A.  600 rpm

B.  1000 rpm

C.  1200 rpm

D.  300 rpm

View Answer:

Answer: Option D

Solution:

100.  The relation among synchronous speed (Ns), rotor speed (Nr) and slip (s) is

A.  Nr = (s – 1)Ns

B.  Nr = (1 – s)Ns

C.  Nr = (1 + s)Ns

D.  Nr = sNs

View Answer:

Answer: Option B

Solution:

MCQ in AC Motors Part 3 | REE Board Exam

DOWNLOAD PDF / PRINT
Print Friendly, PDF & Email
Please do Subscribe on YouTube!

P inoyBIX educates thousands of reviewers and students a day in preparation for their board examinations. Also provides professionals with materials for their lectures and practice exams. Help me go forward with the same spirit.

“Will you subscribe today via YOUTUBE?”

Subscribe

Add Comment

PinoyBIX Engineering. © 2014-2020 All Rights Reserved | How to Donate? | Follow me on Blogarama DMCA.com Protection Status

Math Solution

Advanced Math problem age work mixture digit motion Analytic Geometry 01 problem Analytic Geometry 02 problem clock variation progression misc Combination problem Differential Calculus 01 Problem Differential Calculus 02 Problem Differential Equations Problem Fundamentals in Algebra Fundamentals in Algebra Problem Integral Calculus problem Permutation problem Plane Geometry problem Plane Trigonometry problem Probability problem quadratic equation binomial theorem logarithms Solid Geometry problem Spherical Trigonometry problem System of Numbers Problem Venn Diagram Problem

Questions and Answers in Mathematics

Advanced Math Age Work Mixture Digit Motion Algebra and General Mathematics Analytic Geometry 01 Analytic Geometry 02 Calculus Clock Variation Progression Misc Differential Calculus 01 Differential Calculus 02 Differential Equations Engineering Mathematics Geometry Integral Calculus Plane Geometry Plane Trigonometry Probability and Statistics Quadratic Equation Binomial Theorem Logarithms Solid Geometry Spherical Trigonometry System of Numbers Trigonometry

video

Pre-board in Electronics Engineering

Answers Pre-board in Electronics Engineering - Answers

Questions and Answers

Basic Television - Grob TV Boylestad Questions and Answers Computer Principles Electrical Circuit Electricity and Magnetism Fundamentals Electronic Circuits Floyd Questions and Answers Floyd Self-test Gibilisco Questions and Answers Grob Questions and Answers Industrial Electronics Principles and Applications Malvino Questions and Answers Microelectronics Power Generators / Sources / Principles and Applications Solid State Devices Tests and Measurements Vacuum Tubes

Pre-board in Communications Engineering

Answers

Questions and Answers

Acoustics Antennas Blake Questions and Answers Broadcasting and Cable TV System Digital Communication Networks Forouzan Frenzel Self-test Kennedy Questions and Answers Microwave Communications Miscellaneous Questions in Communications Modulation Navigational Aids and Radar Systems Noise Optical Fiber Communications Radiation and Wave Propagation Satellite Communications Transmission Fundamentals Wire and Wireless Communications

GEAS Solution

Dynamics problem Economics problem Physics problem Statics problem Strength problem Thermodynamics problem

Pre-board in GEAS

Questions and Answers in GEAS

Engineering Economics Engineering Laws and Ethics Engineering Management Engineering Materials Engineering Mechanics General Chemistry Giancoli Physics Physics Strength of Materials Thermodynamics
Online Tool: Electrical Charge Conversions
Online Tool: Electrical Charge Conversions
Online Tool: Color Code Conversions
Online Tool: Color Code Conversions
Online Tool: Weight Measurement Conversions
Online Tool: Weight Measurement Conversions
Online Tool: Temperature Measurement Conversions
Online Tool: Temperature Measurement Conversions