Electrical Machines Objective Questions – Set 18

If B is flux density, l the length of the conductor and v the velocity of the conductor, then emf is given by

The armature of DC machine is made of silicon steel lamination to

When Flemings right hand rule to find the direction of induced emf, the thumb points towards

In Dc generators, electric current to the external circuit from armature is given through

The brushes of a DC machine should be placed on the

The armature of DC generator is laminated to

Width of a carbon brush should be equal to

In a DC machine

The ventilating ducts in most of DC machine are

If field current is decreased in shunt dc motor, the speed of the motor

The bearings used to support the rotor shafts are generally

Lamination of core are generally made of

In a DC generator, if P be the number of poles and N be the rpm of the rotor, then frequency of magnetic reversals will be

Poles of DC machine are often laminated to

In Dc machine, the armature windings are placed on the rotor because of necessity for

In DC generators, the brushes remain in contact with conductors which

07․ The polarity of a DC generator can be reversed by

The purpose of providing dummy coils in a generator is

The emf induced in a conductor rotating in a bipolar field is

In a DC generator if field winding attains the critical resistance

In an ideal DC generator the regulation is

The number of brushes in a commutator depends on

In a commutator

Copper brushes in DC machine are used

A DC generator beyond critical resistance will generate

Armature of DC machine is made of

The insulating material used between the commutator segments is normally

The resistance of armature winding depends on

The teeth in the armature of a DC machines are sometimes skewed. This is done to reduce

What are slot wedges in a DC machine made of?