ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION AUGUST 2012

Overvoltage relay device function number

• 64

• 56

• 60

• 59

A test used to determine the equivalent resistance of an induction motor is _.

• No-load Test

• Short-circuit Test

• Blocked-rotor Test

• Polarity Test

The unit of retentivity is

• Ampere turn

• ampere turn/weber

• ampere turn/meter

• dimensionless

in running condition the rotor reactance of 3Φ induction motor is proportional to

• induced emf

• slip

• supply voltage

• rotor resistance

The ratio of the total flux to useful flux is called _.

• Mutual flux

• Flux Factor

• Leakage Factor

• Magnetic Factor

With reduction of load on alternator

• the frequency decreases

• the frequency increases

• the frequency oscillates

• the frequency remains the same

The process by which metallic parts are demagnetized is called

• degreasing

• degaussing

• degrading

• demagnetizing

The gas inside the inner discharge tube of a sodium vapor lamp is

• Argon

• Neon

• Nitrogen

• Helium

What is the nature of the current flowing in the armature of DC machine?

• pulsating dc

• pure dc

• rectified dc

• alternating current

Which of the following frequencies has the longest period?

• 1 Hz

• 10 Hz

• 1 kH

• 100 kHz