ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION AUGUST 2018

This is the compact arrangement of switching devices.

• Circuit protector

• Switchboard

• Switchgear

• Panelboard

With reference to armature windings, wave windings, wave windings are often called_______ windings

• Cascade

• Series

• parallel

• ring

In case of delta connected circuit, when one resistor is open, power will be

• unaltered

• reduced to 1/9

• reduced to 1/16

• reduced by 1/3

Residual magnetism is necessary in a

• separately excited generator

• self-excited generator

• both of these

• none of these

Inside a hollow spherical conductor

• electric field is zero

• electric field is constant

• electric field changes with distance from the center of the sphere

• electric field is unity

The dummy coil in dc machines is used to

• eliminate reactance voltage

• eliminate armature reaction

• bring about mechanical balance of armature

• eliminate harmonics developed in the machine

In an ACB sequence balanced 3 phase system, the angle between the line voltage and the line current is 50°, what is the lagging power factor of the system?

• 0.30

• 0.50

• 0.64

• 0.94

An ideal full-wave rectifier with non-inductive load has zero transformation losses. What is the efficiency?

• 70%

• 80%

• 90%

• 100%

If the of a dc shunt motor is opened

• it will continue to run at its rated speed

• the speed of the motor will become very high

• The motor will stop

• the speed of the motor will decrease

The condition of a liquid electrolyte is measured in terms of its

• current value

• specific gravity

• acid content

• voltage output