Energy Conversion

An ideal transformer is one in which

If a power transformer is operated at very high frequencies, then

With respect to the direction of rotation, interpoles on a dc motor must have the same polarity as the main poles

The open circuit test on a transformer is always made on

In the short circuit test in a transformer, winding is generally short-circuited.

In a dc motor, the brushes are shifted from the mechanical neutral plane in a direction opposite to the rotation to

The number of cycles generated in a 6-pole alternator in one revolution is

If the lagging load power factor of an alternator is decreased, the demagnetizing effect of armature reaction

In very large dc motors with severe heavy duty, armature reaction effects are corrected by

The amount of copper in the primary is _____ that of secondary.

The open-circuit test on a transformer gives

The speed of a _____ motor is practically constant.

If the excitation of an alternator operating in parallel with other alternators is decreased, its

The distribution of load between two alternators operating in parallel can be changed by changing

When the secondary of a transformer is short-circuited, the primary inductance

The deciding factor in the selection of a dc motor for a particular application is its _____ characteristic.

The rotor of a turbo-alternator is made cylindrical in order to reduce

The disadvantage of a short-pitched coil is that

The demand for a large increase in torque of a dc shunt motor is met by a

For 20% increase in current, the motor that will give the greatest increase in torque is _____ motor.