Electrical Machines Objective Questions – Set 4

The condition for maximum running torque is

The air gap between the yoke and armature is dc machine is kept very small

DC machine is a

Generators works on the principle of production

Dynamic braking is employed to brake

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

Induction motor operation depends on

In circle diagram for induction motor, diameter of circle represents which of the following ?

Which of the following pairs is/are correct?

The motor operate in stable region at which of the following slip?

When maximum starting torque is obtained, rotor power is

A 4 pole dc generator is running at 1500 rpm the frequency of current in the armature winding is

At stand still condition the value of slip is

Which of the following motors is /are widely used?

The sequence of induction motor is RYB, then the direction of induction motor can be changed by which of the following sequence?

Which of the following induction motor has the highest starting torque?

Find the number of poles required, when the frequency is 50Hz and speed of the motor is 500 rpm?

A commutator in dc machine provide ----------------- rectification?

A 4 pole 50 Hz induction motor is running at 1470 rpm. The frequency of rotor current is

Which of the following machines have highest power factor with respect to magnetizing current?

For P pole machine relation between electrical degrees and mechanical degrees is

The speed of rotating magnetic field of 8 pole 50 Hz induction motor is

Which of the following motor has negative speed regulation?

A triangular mmf wave is produced in the air gap of an electric machine. Such wave is produced by

Slot wedges in a dc machine is made up of

A 4 pole 50 Hz induction motor is running at 1470 rpm. What is the slip value?

Dynamic braking is very effective for

Which of the following will vary the maximum torque?

Dynamic braking can be used for

In a DC motor under constant terminal voltage what is the relation between torque (T_e) and power (P)