Questions and answers for exam Preparation

MCQs

Total Questions : 377 | Page 36 of 38 pages

Question 351. In a D.C. generator the critical resistance can be increased by_____________?

increasing its field resistance
decreasing its field resistance
increasing its speed
decreasing its speed

Discuss Question

Answer: Option C. -> increasing its speed
NO EXPLANATION IS AVAILABLE FOR THIS QUESTION!

Question 352. Armature reaction in a generator results in_____________?

demagnetisation of leading pole tip and magnetisation of trailing pole tip
demagnetisation of trailing pole tip and magnetisation of leading pole tip
damagnetising the center of all poles
magnetising the center of all poles

Discuss Question

Answer: Option A. -> demagnetisation of leading pole tip and magnetisation of trailing pole tip
NO EXPLANATION IS AVAILABLE FOR THIS QUESTION!

Question 353. In a D.C. generator:___________________?

external resistance = internal char-acteristic – armature reaction
internal characteristic = magnetisation characteristic – ohmic drop
external characteristic = magnetisation characteristic – ohmic drop – armature reaction
magnetisation characteristic = external characteristic

Discuss Question

Answer: Option C. -> external characteristic = magnetisation characteristic – ohmic drop – armature reaction
NO EXPLANATION IS AVAILABLE FOR THIS QUESTION!

Question 354. Following energized winding of a D.C. machine should not be opened as it would produce high inductive voltage which may be dangerous to personnel and may cause its own insulation failure.

Series field
Compensating field
Inter pole field
Shunt field

Discuss Question

Answer: Option D. -> Shunt field
NO EXPLANATION IS AVAILABLE FOR THIS QUESTION!

Question 355. The number of armature parallel paths in a two-pole D.C. generator having duplex lap winding is______________?

Discuss Question

Answer: Option B. -> 4
NO EXPLANATION IS AVAILABLE FOR THIS QUESTION!

Question 356. Wave winding is composed of_______________?

any even number of conductors
any odd number of conductors
that even number which is exact multiple of poles + 2
that even number which is exact multiple of poles

Discuss Question

Answer: Option C. -> that even number which is exact multiple of poles + 2
NO EXPLANATION IS AVAILABLE FOR THIS QUESTION!

Question 357. The critical resistance of the D.C. generator is the resistance of_____________?

field
brushes
armature
load

Discuss Question

Answer: Option A. -> field
NO EXPLANATION IS AVAILABLE FOR THIS QUESTION!

Question 358. The series field of a short-shunt D.C. generator is excited by_______________?

external current
armature current
shunt current
load current

Discuss Question

Answer: Option D. -> load current
NO EXPLANATION IS AVAILABLE FOR THIS QUESTION!

Question 359. When two D.C. series generators are running in parallel, an equilizer bar is used________________?

to increase the speed and hence generated e.m.f.
to increase the series flux
so that two similar machines will pass approximately equal currents to the load
to reduce the combined effect of ar-mature reaction of both machines

Discuss Question

Answer: Option C. -> so that two similar machines will pass approximately equal currents to the load
NO EXPLANATION IS AVAILABLE FOR THIS QUESTION!

Question 360. The main factor which leads to unstable parallel operation of flat and over compounded generators is_____________?