[Set 4]Electrical Engineering Interview Questions|Electrical Questions And Answers

Electrical Questions and Answers: In this Post, Electrical Engineering Interview Questions and answers are given.

Contents

Electrical Questions and Answers

Type of house wiring?

i. Concealed conduit wiring

ii.Surface conduit wiring

iii. Metal sheathed wiring

iv.C.T.S or Batton wiring .

v.Wooden casin and capping wiring .

vi. Cleat wiring

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What are the types of Wire Joint?

i. Straight twist joint.

ii.Britanna joint.

iii. Married joint.

iv.Scarf joint.

v.Tee joint.

vi.Duplex joint.

vii. Pigtail joint.

What are the type of Switch ?

i. One way switch

ii. Two Way Switch.

iii.Two Way Center off Switch

iv. Double Pole Man Switch.

v. Bed Switch.

vi. Push Button Switch.

vii. Intermediate Switch

What are the types of Drawing Scale?

Drawng Scale are Three types.

1.Reducing Scale 2. True Scale 3. Large Scale

What is a Motor Starter ? Types of Starter ?

(i) DOL Stater.

(ii) Star/Delta Stater

(iii) Autotransformer Starter.

A motor starter is an electrical device that is used to start & stop a motor safely. Similar to a relay, the motor starter switches the power ON/OFF & unlike a relay, it also provides a low voltage & overcurrent protection

DOL starter

A DOL starter (also known as a direct on line starter or across the line starter) is a method of starting a 3 phase induction motor.

In a DOL Starter, an induction motor is connected directly across its 3-phase supply,and the DOL starter applies the full line voltage to the motor terminals.

Star/Delta Starter

Star/Delta starters are probably the most common reduced voltage starters.

They are used in an attempt to reduce the start current applied to the motor during start as a means of reducing the disturbances and interference on the electrical supply.

Autotransformer starter

The autotransformer starter can be used for starting both star and delta connected 3-phase induction motors.

In this method, the starting current of the motor is limited by using a 3-phase autotransformer to decrease the initial applied voltage to the stator.

What is a BLDC Motor?

BLDC motor stands for Brushless Direct Current Motor and as the name suggests, it works on direct current electricity. BLDC motor uses permanent magnets, instead of electromagnets that are used in conventional motors.

The permanent magnets of BLDC motor have less energy and heat losses compared to electromagnets.

Difference between isolator and circuit breaker?

Isolators are manually-operated device, and on the contrary, the circuit breaker is the automatically-operated device.

Isolators cut the portion of the substance when a fault occurs. The other devices like MCB and RCCB operate without any interruption .

What is corona effect ? is it a loss ? Which Factors affecting Corona?

The phenomenon of ionization of air surrounding the high voltage transmission lines causing the conductors to glow, producing a hissing noise and produce ozone gas is called Corona Discharge or Corona Effect.

(i)The glow appear across the conductor which shows the power loss occur on it.

(ii)The corona effect generates the ozone because of which the conductor becomes corrosive.

(iii)The corona effect produces the non-sinusoidal signal thus the nonsinusoidal voltage drops occur in the line.

Factors affecting Corona

(i) atmosphere : As corona is formed due to ionsiation of air surrounding the conductor, therefore,it is affected by the physical state of atmosphere.

(ii) Conductor size : The corona effect depend upon the shape and condition of the conductor.The rough and irregular surface will give rise to more corona because unevenness of the surface decreases the valu of breakdown voltage.

(iii) Spacing between conductor : If the spacing between the conductor is made very large as compared to the diameters, there may not be any corona effect.

(iv) Line voltage : The line voltage greatly affects corona. If it is low, there is no change in the condition of air surrounding the conductors and hence no corona is formed.