Interview Questions Answers in Electrical Engineering, Electronics Communications

Questions / { jyotiba shinde }

Questions Answers Category Views Company eMail

How to model "IF ELSE" statement in matlab simulink?

4 Electrical Engineering 21729

How to model "to find the cube root of the given number" in Matlab Simulink ?

1 Electrical Engineering 8801

Answers / { jyotiba shinde }

Question { TATA, 5690 }

WHERE MODERN TECHNOLOGY USEING IN STEEL INDUSTRY.AND WHAT
IS THE NAME OF THE TECHNOLOGY

Answer

In JSW Steels Pvt. Ltd,Bellary.
It uses the modern furnace to make the hot iron known as
COREX.It has 2 nos of COREX furnac.
Presently Essar Steel,Gujrath goining to install COREX.

Is This Answer Correct ?

12 Yes

1 No

Question { 3099 }

why some harmonics are disturbing while the others not

Answer

Due to the half wave symmetry the even harmonics are not
present in supply.Odd harmonics such as
fundamental,3rd,5th,7th etc have the effect on the power
system.The 5th hormonics are produce the rotating field in
the opposite direction of main field, while 7th harmonics
in same direction.

Is This Answer Correct ?

2 Yes

0 No

Question { 3138 }

what's the reson that,Load is not same on VFD I/P and O/P
Side.whenever DOL condition load is same I/P and O/P side.

Answer

We know that Power out=Torque*speed in rps.
Since in DOL condition there is no speed changing means no
change in power out,while in VFD there will be speed
changing using the frequency control,so the power out
changes from power input in VFD(Assuming that torque is
constant).

Is This Answer Correct ?

3 Yes

0 No

Question { Saint Gobain, 8209 }

how to find the resistance

Answer

To find the resistance of the conducting device, apply the
ohms law to it. That is connect the voltage source to it,
apply the voltage and note down the current and volotage.
By using the formula V=I*R, calculate the Resistance R.

Is This Answer Correct ?

13 Yes

0 No

Question { Hindalco, 7052 }

in case of three phase induction motor,when it is connected
to three phase supply,why the magnetic field is rotets
around the armeture?

Answer

Since the suplly is of 3 phase sinusoidal in nature, flux
produced due to htis in the stator is of alternating in
nature.This flux is cut by the stationary conductor on the
rotor, thus eddy currents are induced in the rotor circuit
by Lenz's law.To overcome force produced by these currents
and induced flux the rotor starts rotating in the direction
of flux.

Is This Answer Correct ?

8 Yes

0 No

Question { Visa Steel, 6977 }

what is bushing in transfermor

Answer

Bushings are the insulators provided between transformer
tank(or panel) and live conductors both primary and
secondary sides of the transformer.

Is This Answer Correct ?

7 Yes

2 No

Question { 5718 }

Why we oil in tranformer/

Answer

Oil is used for the two purpose,
1. For the purpose of insulation between primary n
secondary.
2. For the purpose of cooling of the windings.

Is This Answer Correct ?

19 Yes

0 No

Question { 10927 }

how calculate cable size in squre mm, when the load is
given by in kw? do u have current rating chart of elctrical
cables?

Answer

With knowing the kW rating and voltage, the current can be
calculated as I=P/(sr(3)*V*pf). The pf can be assumed to be
as 0.8. After knowing the current, choose the 10% higher
current carrying capacity cable for the safety purpose.

current rating for differnt cables are different for same
size.Copper has higher current carrying capacity.

Is This Answer Correct ?

10 Yes

2 No

Question { 7551 }

I have three phase 400 KW,390 A MOTOR.For this motor which type
of Cable is required....specifically rubber cable required. Can
anyone help me..

Answer

You mentioned the current capacity of motor is 390A, If
distance is too closer to the breaker,then you might be go
for copper cable, it will have lesser cross section and
high current carrying capacity. If the distance is more
better to go for the Aluminium cable so that cost of the
cable will reduce from the copper cable.

Is This Answer Correct ?

2 Yes

0 No

Question { 3258 }

1. name the relay for protecting transformer
2. Current Transformer
3. potential Transformer

Answer

1.Bucholz relay
2.Current measurement
3.Voltage measurement

Is This Answer Correct ?

2 Yes

3 No

Question { 4302 }

how can we use isolator as breaker

Answer

Basically isolator is an switch manually used to off the
circuit.Isolator with fuse unit can do function of breaker
that is over load tripping by fuses.

Is This Answer Correct ?

4 Yes

2 No

Question { 11333 }

what is the formula to calculate kva genset required for a
given load in kw.

Answer

kVA=kW/pf

Is This Answer Correct ?

12 Yes

4 No

Question { 2969 }

Name of Hydrocarbon gases.

Answer

The Hydrocarbon gases are
Methane(CH4),Ethane(c2H6) .....etc

Is This Answer Correct ?

8 Yes

0 No

Question { 5959 }

How reverse power relay sense the power is reverse in the
system.

Answer

The Reverse power relay is of Directional Relay.
The function of the Direction Relay is to sense(activate) if
the direction of the power is changed.

Is This Answer Correct ?

8 Yes

1 No