Electrical Engineering Mcqs Practice Test

Question 1

Shunt generators are most suited for stable parallel operation because of their______________?

Accepted Answer

C. drooping voltage characteristics

Question 2

As a result of armature reaction, the reduction in the total mutual air gap flux in a D.C. generator is approximately______________?

Accepted Answer

D. 5 percent

Question 3

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

Accepted Answer

A. field

Question 4

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

Accepted Answer

D. load current

Question 5

In a separately excited generator supplying rated load the armature reaction.

Accepted Answer

A. is always present

Question 6

For both lap and wave windings, there are as many commutator bars as the number of_____________?

Accepted Answer

C. winding elements

Question 7

Wave winding is composed of_______________?

Accepted Answer

C. that even number which is exact multiple of poles + 2

Question 8

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

Accepted Answer

B. 4

Question 9

In a D.C. generator:___________________?

Accepted Answer

C. external characteristic = magnetisation characteristic – ohmic drop – armature reaction

Question 10

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

Accepted Answer

C. increasing its speed

Question 11

Which generator would you prefer for feeding long D.C. transmission lines ?

Accepted Answer

C. Over compound generator

Question 12

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.

Accepted Answer

D. Shunt field

Question 13

Armature reaction in a generator results in_____________?

Accepted Answer

A. demagnetisation of leading pole tip and magnetisation of trailing pole tip

Question 14

If residual magnetism is present in a D.C. generator, the induced e.m.f. at zero speed will be____________?

Accepted Answer

A. zero

Question 15

The purpose of providing dummy coils in a generator is__________________?

Accepted Answer

D. to provide mechanical balance for the rotor

Question 16

A 220 V D.C. generator is run at full speed without any excitation. The open circuit voltage will be_____________?

Accepted Answer

B. about 2 V

Question 17

A shunt generator running at 1000 r.p.m. has generated e.m.f. as 200 V. If the speed increases to 1200 r.p.m., the generated e.m.f. will be nearly_______________?

Accepted Answer

C. 240 V

Question 18

A sinusoidal voltage of 5 Hz is applied to the field of a shunt generator. The armature voltage wave will_____________?

Accepted Answer

B. will be of 5 Hz

Question 19

The purpose of providing dummy coils in a generator is____________?

Accepted Answer

D. to provide mechanical balance for the rotor

Question 20

In D.C. generators on no-load, the air gap flux distribution in space is______________?

Accepted Answer

D. flat topped