Electrical Machines Objective Questions – Set 19

In a DC shunt generator working on load, the brushes are moved forward in the direction of rotation, as a result of this, commutation will

A Dc generator can be considered as

In a DC generator sparking between brushes and commutator surface may be due to

The self induced emf in the coil undergoing commutation is called the

Which of following components of a DC generator plays vital role for providing direct electric current of a DC generator?

Armature coil is short circuited by brushes when it lies

Armature reaction of an unsaturated DC machine is

If the armature electric current is increased to double its previous value, and the time of commutation is halved, how will the reactance voltage vary?

To achieve spark less commutation brushes of DC generator are rocked ahead so as to bring them

The demagnetising component of armature reaction in a DC generator

Current in a coil undergoing commutation is not able to get reversed completely by the end of commutation period. It is due to

Satisfactory commutation of DC machine requires

The terminal voltage of a DC shunt generator drops on load because of all of the following reasons except

The voltage drop for which of the following types of brush can be expected to be least ?

Commutation in a DC machine may be explained as a process

Iron losses in a DC machine are independent of variation in

In a DC generator the actual flux distribution depends upon

The commutator segments are connected to the armature conductors by means of

In a DC generator the ripples in the direct emf generated are reduced by

The change in speed of a DC generator due to increased load is corrected by

Compensating windings are used in DC generators

In a DC generator, the armature reaction results in

Sparkless commutation can be achieved by employing

In a DC generator in case the brushes are moved so as to bring them in magnetic neutral axis, then, there will be

In a DC generator in order to reduce sparking at brushes, the self-induced emf in the coil is neutralized by all of the following except

Under commutation results in

The rapid wear of brushes takes place due to

In DC generators, the cause of rapid brush wear may be

Number of tappings for each equalizer ring is equal to

To have sparkless commutation, the armature reaction effect in a DC machine is neutralized by