Electrical Machines Objective Questions – Set 4

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

Which of the following motor has negative speed regulation?

DC machine is a

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

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

Generators works on the principle of production

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

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

The condition for maximum running torque is

Dynamic braking is employed to brake

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

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

Slot wedges in a dc machine is made up of

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

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

Which of the following motors is /are widely used?

When maximum starting torque is obtained, rotor power is

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

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

Dynamic braking can be used for

Which of the following will vary the maximum torque?

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

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

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

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

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 pairs is/are correct?

Dynamic braking is very effective for

Induction motor operation depends on

At stand still condition the value of slip is