Study mode · no timer

D.C. Generators

Study 120 Electrical Engineering MCQs with correct answers and explanations.

Answers and explanations are always visible Take this test

101Electrical EngineeringMedium

Two generators A and B have 6-poles each. Generator A has wave wound armature while generator B has lap wound armature. The ratio of the induced e.m.f. is generator A and B will be________?

A1 : 3

B3 : 2

C3 : 1

D2 : 3

Correct answer

C. 3 : 1

Explanation

The correct answer is 3 : 1.

102Electrical EngineeringMedium

Permeance is the reciprocal of________?

Aampere-turns

Bflux density

Cresistance

Dreluctance

Correct answer

D. reluctance

Explanation

The correct answer is reluctance.

103Electrical EngineeringMedium

Two D.C. shunt generators, each with armature resistance of 0.02 ohm and field resistance of 50 ohm run in parallel and supply a total current of 1000 amperes to the load circuit. If their e.m.fs. are 270 V and 265 V, their bus bar voltage will be________?

A265 V

B267.5 V

C257.4 V

D270 V

Correct answer

B. 267.5 V

Explanation

The correct answer is 267.5 V.

104Electrical EngineeringMedium

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

Correct answer

D. 4

Explanation

The correct answer is 4.

105Electrical EngineeringMedium

Which of the following generator will have negligible terminal voltage while running on no-load?

ASeparately excited generator

BShunt generator

CCompound generator

DSeries generator

Correct answer

D. Series generator

Explanation

The correct answer is Series generator.

106Electrical EngineeringMedium

In a D.C. generator the critical resistance refers to the resistance of________?

Aload

Bbrushes

Cfield

Darmature

Correct answer

C. field

Explanation

The correct answer is field.

107Electrical EngineeringMedium

In case of a flat compounded generator:

Agenerated voltage is proportional to the load on the generator

Bvoltage remains constant irrespective of the load

Cspeed varies in proportion to the load on the generator

Dvoltage generated is less than the rated voltage

Correct answer

B. voltage remains constant irrespective of the load

Explanation

The correct answer is voltage remains constant irrespective of the load.

108Electrical EngineeringMedium

Armature reaction of an unsaturated D.C. machine is________?

Acrossmagnetising

Bdemagnetising

Cnone of above

Dmagnetising

Correct answer

A. crossmagnetising

Explanation

The correct answer is crossmagnetising.

109Electrical EngineeringMedium

In the case of lap winding resultant pitch is________?

Asum of front and back pitches

Bdivision of front pitch by back pitch

Cmultiplication of front and back pitches

Ddifference of front and back pitches

Correct answer

D. difference of front and back pitches

Explanation

The correct answer is difference of front and back pitches.

110Electrical EngineeringMedium

Interpole flux should be sufficient to________?

Aneutralise the armature reaction flux

Bperform none of the above functions

Cneutralise the commutating self induced e.m.f.

Dneutralise both the armature reaction flux as well as commutating e.m.f. induced in the coil

Correct answer

D. neutralise both the armature reaction flux as well as commutating e.m.f. induced in the coil

Explanation

The correct answer is neutralise both the armature reaction flux as well as commutating e.m.f. induced in the coil.

In case of a flat compounded generator:

Agenerated voltage is proportional to the load on the generator

Bvoltage remains constant irrespective of the load

Cspeed varies in proportion to the load on the generator

Dvoltage generated is less than the rated voltage

Correct answer

B. voltage remains constant irrespective of the load

Explanation

The correct answer is voltage remains constant irrespective of the load.

Interpole flux should be sufficient to________?

Aneutralise the armature reaction flux

Bperform none of the above functions

Cneutralise the commutating self induced e.m.f.

Dneutralise both the armature reaction flux as well as commutating e.m.f. induced in the coil

Correct answer

D. neutralise both the armature reaction flux as well as commutating e.m.f. induced in the coil

Explanation

The correct answer is neutralise both the armature reaction flux as well as commutating e.m.f. induced in the coil.