## Electrical Machines In field flux method speed control of DC Motor is

constant torque drive below the base speed.
constant torque drive above the base speed.
constant power drive above base speed.
constant hp drive below the base speed.

## Electrical Machines The mechanical power is developed by a DC motor is maximum when

back emf is equal to half of applied voltage.
none of above.
back emf is equal to twice of applied voltage.
back emf is equal to applied voltage.

0.5 Amp.
400 Amp.
800 Amp.
320 Amp.

## Electrical Machines At slip s = 1 torque developed in machine is

electromagnetic torque.
starting torque.
none.
maximum torque.

## Electrical Machines Which of the following DC Motor uses 4-point starter?

DC shunt motor with field weaking control.
DC compound motor.
DC series motor.
DC shunt motor with armature resistance.

## Electrical Machines A 3 - ÃŽÂ¦, 4 pole IM is supplied from a 50 Hz source. Calculate rotor frequency when rotor runs 600 rpm?

Can be determined.
30 Hz.
20 Hz.
35 Hz.