Sail E0 Webinar

MCQs

Total Questions : 395 | Page 39 of 40 pages
Question 381. 6. The mechanical power developed by a synchronous motor is independent of
  1.    applied stator voltage
  2.    torque angle
  3.    field excitation
  4.    speed
 Discuss Question
Answer: Option D. -> speed
Question 382. 5. At full-load, the rotor poles of a synchronous motor are displaced by a mechanical angle of 1? from their no-load position. If the machine has 40 poles, then torque angle is
  1.    40? electrical
  2.    20? electrical
  3.    100 electrical
  4.    none of the above
 Discuss Question
Answer: Option B. -> 20? electrical
Question 383. 7. When a synchronous motor is pulled out of synchronism, the stator current
  1.    becomes zero
  2.    is increased too much
  3.    is decreased too much
  4.    remains unchanged
 Discuss Question
Answer: Option B. -> is increased too much
Question 384. 0. When a unity p.f. synchronous motor is operated at a leading p.f., it results in
  1.    more than rated horsepower output
  2.    more than rated stator current
  3.    less than rated horsepower output
  4.    none of the above
 Discuss Question
Answer: Option B. -> more than rated stator current
Question 385. 1.  A synchronous motor is cheaper than 3-phase induction motor for
  1.    high speed, high output
  2.    high speed, low output
  3.    low speed, high output
  4.    none of the above
 Discuss Question
Answer: Option C. -> low speed, high output
Question 386. 6. A 18.-65 kW, 220 V, 50 Wz, 4-pole, Y-connected synchronous motor is running with a light load. The load angle is 4?(elect.) and back e.m.f. generated per phase in 110 V. If the armature resistance per phase is 0.10 and synchronous reactance / phase is 1.511, then resultant armture voltage/phase is
  1.    5.4 V
  2.    18.9 V
  3.    72.4 V
  4.    26.8 V
 Discuss Question
Answer: Option B. -> 18.9 V
Question 387. 7.  An over-excited synchronous motor running in parallel with induction motors can be used in improve the power factor of
  1.    supply line
  2.    transformer
  3.    generators
  4.    all of the above
 Discuss Question
Answer: Option D. -> all of the above
Question 388. 5. When load on a synchronous motor running with normal excitation is increased, armature current drawn by it increases because
  1.    back e.m.f. Eb becomes less than the applied voltage V
  2.    power factor is decreased
  3.    net resultant voltage Er in armature is increased
  4.    motor speed is reduced
 Discuss Question
Answer: Option C. -> net resultant voltage Er in armature is increased
Question 389. 2. Synchronous motors are generally used in applications requiring
  1.    infrequent starting
  2.    variable speed
  3.    sudden application of heavy loads
  4.    frequent stopping
 Discuss Question
Answer: Option A. -> infrequent starting
Question 390. 3. In a synchronous motor, the magnitude of stator back e.m.f. Eb depends on
  1.    speed of the rotor
  2.    load on the motor
  3.    both the speed and rotor flux
  4.    d.c. excitation only
 Discuss Question
Answer: Option D. -> d.c. excitation only

Latest Videos
Chapter 1 - GLOBAL STEEL SCENARIO & INDIAN STEEL INDUSTRY Part 1 : (13-04-2024) INDUSTRY AND COMPANY AWARENESS (ICA)
Direction Sense Test Part 1 Reasoning (Hindi)
Chapter 1 - RMHP / OHP / OB & BP Part 1 : (14-02-2024) GPOE
Cube & Cuboid Part 1 Reasoning (Hindi)
Data Interpretation (DI) Basic Concept Reasoning (Hindi)
Counting Figures Part 1 Counting Of Straight Lines Reasoning (Hindi)
Sail E0 free webinar Webinars
Real Numbers Part 7 Class 10 Maths
Real Numbers Part 1 Class 10 Maths
Polynomials Part 1 Class 10 Maths

Latest Test Papers

Pie Chart - Test Paper 1 Data Interpretation Reasoning & DI
Tabulation - Test Paper 2 Data Interpretation Reasoning & DI
Test Paper 1 Direction Sense Test Reasoning & DI
ICA , RDIC,GFM Free Modal Test Paper - Non - Technical Branch Old Syllabus 2022 - SAIL Junior Officer E0
GFM Combined 1 Free Revision Test SAIL JO E-0