Electrical Engineering MCQs

Page No. 243

The back e.m.f. in the stator of a synchronous motor depends on____________?


anumber of poles

✖


b flux density

✖


crotor speed

✖


drotor excitation

✓


View Answer rotor excitation

If the field of a synchronous motor is underexcited, the power factor will be_____________?


azero

✖


bunity

✖


clagging

✓


d leading

✖


View Answer lagging

In a synchronous motor, the damping winding is generally used to______________?


areduce noise level

✖


breduce the eddy currents

✖


cprovide starting torque only

✖


dprevent hunting and provide the starting torque

✓



In a synchronous motor it the back e.m.f. generated in the armature at noload is approximately equal to the applied voltage, then


athe motor is said to be fully loaded

✖


bthe torque generated is maximum

✖


cthe excitation is said to be zero per cent

✖


dthe excitation is said to be hundred per cent

✓



In a 3-phase, 4-pole, 50 Hz synchronous motor, the frequency, pole number and load torque all are halved. The motor speed will be____________?


a3000 r.p.m.

✖


b1500 r.p.m.

✓


c750 r.p.m.

✖


d none of the above

✖


View Answer 1500 r.p.m.

In a synchronous motor, V-curves represent relation between____________?


aarmature current and field current

✓


bpower factor and speed

✖


cfield current and speed

✖


d field current and power factor

✖



By which of the following methods the constant speed of a synchronous motor can be changed to new fixed value ?


aBy changing the supply frequency

✓


bBy interchanging any two phases

✖


cBy changing the applied voltage

✖


dBy changing the load

✖



The torque angle, in a synchronous motor, is the angle between_______________?


a the supply voltage and the back e.m.f.

✖


bmagnetising current and back e.m.f

✖


cthe rotating stator flux and rotor poles

✓


dnone of the above

✖



A 3-phase synchronous motor is running clockwise. If the direction of its field current is reversed


athe motor will stop

✖


b the motor continue to run in the same direction

✓


cthe winding of the motor will burn

✖


dthe motor will run in the reverse direction

✖



The net armature voltage of a synchronous motor is equal to the_______________?


avector sum of Eb and V

✖


barithmetic sum of Eb and V

✖


carithmetic difference of Eb and V

✖


dvector difference of Eh and V

✓



Goto Page No.

Page 243 of 366

Alphabetical MCQs Categories
—

Here below You find all kind of categories of MCQs in alphabetical order.


"Comprehensive Collection of MCQs: Alphabetically Organized by Subject"
—

"Discover an extensive collection of multiple-choice questions (MCQs) neatly categorized by subject from A to Z. This resource is designed for anyone eager to explore various topics in a straightforward and organized manner. Whether you're a student preparing for exams, an educator seeking supplementary materials, or simply curious about different subjects, this compilation offers a convenient way to learn and assess your knowledge. With questions arranged alphabetically, navigation is effortless, allowing you to delve into subjects of interest at your own pace. Engage, learn, and expand your understanding with this accessible and comprehensive repository of MCQs!"


BolPakistan

bolpakistan.com.pk includes Job Mcqs and Pak Mcqs is the Top Largest Mcqs Forum in World, in which you can read Mcqs of All Subjects, PPSC test preparation, FPSC, NTS and PPSC PAST PAPERS, PPSC PAST MCQS. A Collection of Repeated MCQs for JOBs seekers.

Copyright © 2024, Designed & Developed by BolPakistan