List of top Electrical Engineering Questions on Electrical Machines

An 8085 microprocessor executes an instruction in 4 machine cycles containing 4, 3, 3, and 3 T-states respectively. If the clock frequency is 3 MHz, the execution time is approximately

The slip of a 3-\(\phi\), 50 Hz, induction motor fed by 3-\(\phi\), 50 Hz inverter is 's' at fundamental frequency. At \(5^{\text{th}}\) harmonic frequency, the harmonic slip is nearly equal to

Compared with an induction motor, AC servo motor speed-torque characteristics and X/R ratio respectively are

The swing equation of a synchronous generator is

Frequency of rotor current of a 3-\(\phi\), 4-pole, 50 Hz induction motor is 3 Hz. Speed of the motor is

When the supply voltage to an induction motor is reduced by 10%, the maximum torque will be decreased approximately by

Two 3-\(\phi\) induction motors with \( p_1 \) and \( p_2 \) poles are cascaded together. Then the possible number of speeds are

In torque-slip curve of a 1-\(\phi\) induction motor, the backward torque is

When load current of a dc series motor is increased, then

The disadvantage of Hopkinson's test on two dc shunt machines is

Slope of the tangent drawn on initial portion of O.C.C of synchronous generator is

If the locus of minimum armature currents of V-curves of synchronous motor is a straight line, then the slope of the line is

If \( \delta \) is load angle, the real power of 3-\(\phi\) synchronous motor is

Speed of a 3-\(\phi\), 4-pole, 60 Hz induction motor at 75% of full-load is 1700 rpm. The speed at full-load can be

A transformer has full load copper loss of 400 W. The copper loss at half full load will be

The load current of a step down 250/200 V auto-transformer is 100 A. The conductive and inductive powers transformed are

The eddy current loss and hysteresis loss of 1-\(\phi\), 100 kVA, 50 Hz transformer are 4 kW and 6 kW respectively. If frequency is increased by 10%, then total loss is

In a wave winding, if \( y_b \) and \( y_c \) are back and commutator pitches respectively, then the front pitch \( y_f \) is given by

A DC generator with 8-pole, 480 armature conductors, wave winding, draws an armature current of 200 A. When brushes are shifted by \( 6^\circ \) electrical from GNP, the cross-magnetising amp-turn/pole is

To control voltage of a long shunt dc compound generator, a diverter resistance is connected across

The copper and iron losses of a 1-$\phi$ transformer are equal at 90% of full load and its value is 162 W. The total loss at 80% of full load is

In an ideal transformer, which of the following is correct?

In delta-star connection, the phase displacement between the primary voltage and secondary emfs is