Interview Questions Answers in Electrical Engineering

Questions / { rajesh tokalapudi }

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Answers / { rajesh tokalapudi }

Question { Taj Group, 184456 }

What is meant by H.R.C fuse?

Answer

H R C means High Rupturing Capacity.

Is This Answer Correct ?

157 Yes

19 No

Question { 37056 }

What is the meaning of GRID?

Answer

GRID means interconnection of different generating stations
and load centres which are all tuned to constant voltage
and frequency.

Is This Answer Correct ?

28 Yes

13 No

Question { Infosys, 21683 }

How a generator is positioned in a hydroelectric power
plant?

Answer

generators in hydro plants r of salient ploe type.salient
pole generators r having high diameter and less axial
lengh.as a matter of space it is placed vertically over the
hydro turbine to save the place.

Is This Answer Correct ?

23 Yes

2 No

Question { HP, 14857 }

why battery is connected in series?

Answer

batteries r connected in series to increase the voltage
rating as current remains same in series circuit.They r
connected in parallel to get more current rating as voltage
remains same in parallel circuit.

Is This Answer Correct ?

11 Yes

1 No

Question { Essar, 45573 }

what is saturation in transformer

Answer

Transformer saturation means its core
saturation.transformer core is made up of silicon steel
laminations to reduce eddy current losses and to provide
low reluctance path to the flow of flux.all magnetic
materials will experiance a phenomena called hysteresis
loss.in case of transformer also if the primary current
(flux)keep on increasing(acc to load)at a certain stage
hystersis loss will comes to such a stage it will not
further increase.this situation in a transformer is called
as saturation of core.

Is This Answer Correct ?

67 Yes

24 No

Question { 9392 }

what is the differance between ac induction motor and ac
synchronous motor?

Answer

1)induction motor is singly fed motor.Means three phase
supply is given to its stator only.But in case of
synchronous motor which is doubly fed motor 3phase acis
given to stator and dc is given to rotor.

2)generally induction motor is used in all types of
industries where maintainance less and rugged type motor is
needed.where as syschronous motor is used in applications
which demands constant speed.

Is This Answer Correct ?

14 Yes

0 No

Question { JSW, 59225 }

What will happen if 230V DC motor connected to 230V AC
Supply?

Answer

when a dc motor is connected to a ac supply it will run
with reduced efficiency.in case of ac reactance will comes
into picture.so,increased losses due to inductance.and
there is sparking at brushes.motor will run with reduced
speed.

Is This Answer Correct ?

83 Yes

22 No

Question { 48094 }

What is the use of core in the transformer?

Answer

The main purpose of core in a tranformer is to provide a
low reluctance path between primary and secondary.

Is This Answer Correct ?

92 Yes

8 No

Question { Pennar, 60544 }

Why motor initial starting current is high?

Answer

In case of motor current is given by i=(v-e)/r.here
v=suplly voltage,e=back emf and r=resistace.during starting
back emf is zero.then i=v/r.generally motor resistance is
low.so during starting motor draws high current,which is
normally 5 to 6 times its normal operating current.

Is This Answer Correct ?

83 Yes

13 No

Question { IOCL, 24320 }

megger generates D.C. voltage while earth tester generates
A.C.voltage is it true? I know for megger it is D.C
generator but what about earth tester?

Answer

As per my knowlegde there is no much diffrence between
megger and earth megger.megger is used to measure
insulation resisitance(mega ohm)and earth megger is used to
measure earth resistance(ohms).constructionally there is no
difference.both contains an in built permanant magnet hand
driven generator.The difference lies in the no of
terminals.megger contains 3 and earth megger contains 4
terminals.Both will generate dc voltage only during
measurement.

Is This Answer Correct ?

22 Yes

15 No

Question { JSW, 28375 }

why transformer is giving some humming noise .....?

Answer

This is mainly due to magnetostriction.means whenever a
ferro magnetic material is subjected to magnetism its
dimenstions will change.this will results in some noise.

Is This Answer Correct ?

33 Yes

3 No

Question { CESC, 68877 }

Why used in layer by layer charcoal and salt used in earth
pits.

Answer

The layer of charcoal and salt helps to maintain low
resistance for earth fault currents.Because of ionic
behaviour of salt and charcoal they will maintain moisture
content around the earht pit.

Is This Answer Correct ?

114 Yes

10 No

Question { 7394 }

what is the apt definition for kirchoff's current and
voltage laws?

Answer

Kirchoff's current law says that the algebraic sum
currents entering a particular node is equal to the
algebraic sum of currents leaving that particular node.
kirchoff's voltage law says that the algebraic sum of
voltage drops and source voltages in any closed loop is
zero.

Is This Answer Correct ?

21 Yes

3 No

Question { NTPC, 20962 }

what are the types of sus station ?

Answer

There are mainly three types of sub-stations.
1.step up/down substations-where stepping up or stepping
down of voltage has done.
2.power factor improvement sub station-where power factor
is improved by installing capacitor banks or synchronous
condensors.
3.switching sub stations- Where switching action like
switching on or off has done for maintenance purposes for
other reasons.

Is This Answer Correct ?

22 Yes

9 No