Electrical Engineering · Question Bank

DC Generators

146 of 196 questions match · page 3 of 8. Answer in your head first, then check the solution.

📘 EE Mock Board Exam

#41📜 EE Pre-Board August 2018📘 PowerhouseEasy

With reference to armature windings, wave windings are often called _______ windings.

ACascade

BSeries

Cparallel

Dring

#42📘 EE Pocket Reviewer RojasEasy

The yoke of a dc machine is made from which of the following?

ASilicon steel

BAluminum

CSoft iron

DCast steel

#43📘 EE Pocket Reviewer RojasEasy

Which one is the function of the pole in a dc machine?

ATo support the field coils

BTo spread out the flux

CTo reduce the reluctance of the magnetic path

DAll of these

#44📘 EE Pocket Reviewer RojasEasy

In dc machines the mechanical losses are primarily dependent on which of the following?

ACurrent delivered

BVoltage induced

CSpeed

DFlux density

#45📘 EE Pocket Reviewer RojasEasy

Which of the following is the excitation current of the series field in a long-shunt compound dc generator?

AArmature current

BShunt field current

CLoad current

DExternal current

#46📘 EE Pocket Reviewer RojasEasy

What is the reason why a separately-excited dc generator is no longer used today?

AIt is an expensive machine

BThe terminal voltage drops considerably with load

CA separate dc source is required for its field circuit

DIt is only available in low kW rating

#47📘 EE Pocket Reviewer RojasEasy

Shunt generators are the most suited for stable parallel operation due to which of the following voltage characteristics?

ALinear

BIdentical

CRising

DDrooping

#48📘 EE Pocket Reviewer RojasEasy

In dc machines, the armature windings are placed on the rotor because of the necessity for which of the following?

ACommutation

BGeneration of voltage

CDevelopment of torque

DElectro-mechanical energy conversion

#49📘 EE Pocket Reviewer RojasEasy

What is the reason why, the coil span of a dc armature winding must be equal to the pole pitch?

ATo save the length of the coil used for the windings

BTo distribute the windings uniformly under the different poles

CTo ensure the addition of emfs for consecutive turns

DTo make the machine deliver more current at a definite voltage

#50📘 EE Pocket Reviewer RojasEasy

What is the terminal voltage of a series generator running at rated speed and at no load?

AZero

BRated voltage

CMore than its rated voltage

DA very little voltage

#51📘 EE Pocket Reviewer RojasEasy

Which of the following dc generator losses varies with the load connected to the generator?

AEddy current loss

BHysteresis loss

CCopper loss

DFriction and windage loss

#52📘 EE Pocket Reviewer RojasEasy

Which one is considered the real working part of a dc machine?

AArmature windings

BField windings

CArmature core

DCommutator and brushes

#53📘 EE Pocket Reviewer RojasEasy

How much is the commutator pitch for a simplex lap winding?

AEqual to the pole pitch

BEqual to twice the pole pitch

CEqual to 1

DEqual to half the pole pitch

#54📘 EE Pocket Reviewer RojasEasy

Which of the following would cause a generator to fail to build up?

AReversed field connections

BSpeed too low

CGenerator is short-circuited

DAll of these

#55📘 EE Pocket Reviewer RojasEasy

Which of the following is true about a dc machine having four poles?

AAll four poles are north poles

BAll four poles are south poles

CTwo north poles follow two south poles

DAlternate poles are north and south

#56📘 EE Pocket Reviewer RojasEasy

Which type of dc generators is used for arc welding purposes?

ASeries generator

BShunt generator

CCumulatively compounded generator

DDifferentially compounded generator

#57📘 EE Pocket Reviewer RojasEasy

With a dc generator which of the following voltage regulation is more preferred?

A1%

B50%

C100%

D75%

#58📘 EE Pocket Reviewer RojasEasy

Which of the following generators is used for charging automobile batteries?

ASeries generators

BShunt generators

CLong shunt compound generators

DShort shunt compound generators

#59📘 EE Pocket Reviewer RojasEasy

What is the reason for the rapid brush wear in dc generators?

AImperfect contact

BSevere sparking

CRough commutator surface

DAll of these

#60📘 EE Pocket Reviewer RojasEasy

What do you mean by “flashing” in a dc generator?

ATo increase the flux density by adding more turns in the field poles

BTo create residual magnetism by a dc source

CTo perform a short circuit test in the generator

DTo increase the excitation current in the field by lowering the rheostat resistance

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