Interview Questions Answers in Electrical Engineering

Questions / { ramesh behera }

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what is the difference between Resistance VS capacitance

Jindal,

2 Electrical Engineering 4784

Answers / { ramesh behera }

Question { 35031 }

What is the formula for finding fault level of generator?

Answer

From your question I guess there is transformer between the
11kV & 6.6kV you are referring to. We need the transformer
MVA and the impedance percentage.
Once your provide the transformer MVA and its %impedance I
can answer further

mail-behera.ramesh@orisysinfotech.com

Is This Answer Correct ?

0 Yes

1 No

Question { Biocon, 6665 }

what is the difference between Earthing,Grounding and
neutral?

Answer

Earthing is the path through which the current flows towards
earth in faulty condition to protect the system because in
faulty situation this current
will be several times higher than the normal operation.

Neutral is the return path for the current flows in healthy
operating condition

Grounding are the path for which heavy amount of in crush
current will passes
these referring as two types one is Chassis ground for get
neural connection
other is for faulty condition

Is This Answer Correct ?

9 Yes

1 No

Question { 22377 }

how to diffrentiate between ac & dc motors from a distance

Answer

Differentiation between ac & dc motors
1-Ac motor has induction properties but in Dc motor has no.
2-AC motor has starts with a capacitor to leading starting
torque where DC has shunt the field & split ring
3-the outer shape is plane of dc motor or rectangular in shape
where as AC motor has built in split bar cooling.

Is This Answer Correct ?

6 Yes

1 No

Question { Adani, 4632 }

what you mean by current?
what you mean by voltage?
what is difference between star and delta connection in
motor side?

Answer

Current is the flow of electrons It is represent as A = amp
It is the potential difference between two points which
varies with negative to positive It is represent as Volt
In star there is 4 way connection for supply out called one
neutral
3phase
I line= I phase
but in delta = 3way connection
line voltage = phase voltage

for more
BEHERA.RAMESH@orisysinfotech.com

Is This Answer Correct ?

1 Yes

0 No

Question { 16333 }

short notes on npn & pnp transisitor..........

Answer

Basics Of transistor
In NPN transistor a P type semiconductor is dopped in
between two N type semiconductors,
whereas in PNP a N type semiconductor is dopped in between
two P type
semiconductors,
as per diagrams in NPN an arrow is there on emitter in
outward direction,
whereas in PNP transistor arrow is in inward direction
Ex-
BC -548-NPN B→ C →E→

BC 558- PNP B ← C ← E←

Is This Answer Correct ?

3 Yes

2 No

Question { Coastal Energen, 8539 }

WHAT HAPPENING TO TRANSFORMER????
i have the step down transformer rating 230/12v, power
rating something.,,, ok. suppose iam giving 12v to secondary
side,what will happen on primary side.,,,

Answer

The design of transformer are rating in terms of insulation
of core & winding configurations
in 230v/12v transformer the primary winding(230v)
nearer to core & (12v)winding at outer layer
so it is not possible for to step up value to 12v to 230v

by input 230v ac in secondary site(12v)the winding
insulation burn up.
@Ramesh

Is This Answer Correct ?

3 Yes

0 No

Question { 6508 }

how much Watt can we fully load a transformer

Answer

Kw=Kva*0.8
here Kva=45
p.f= 0.8
hence the total load= 45*0.8= 36kw or
36000w

Is This Answer Correct ?

2 Yes

0 No

Question { Suzlon, 4476 }

We have 110Vac ,10A ac supply which is converted into
110VDC & How much DC current? which factor is reqired for
dc current calulation?

Answer

RMS square root mean value of rectifier is 1.414

so 110*1.414= 156v

the amp also differing to according rectifier type to load
in wattage
generally lt also differing 1/4 time from source amp

Is This Answer Correct ?

2 Yes

1 No

Question { DRDO, 59610 }

two bolbs of 100w and 40w respectively connected in series
across a 230v supply.which bolb will glow bright and why?

Answer

Current in series connection is always same and voltage is
divided.here,
resistance of 40W bulb is higher than 100W bulb.
resistance of 40 watt is high so less current required to
glow a 40W bulb.
resistance of 100 watt is low so high current required to
glow a 100W bulb.
high resistance so voltage require more for glows = 40watt
glows more
similarly ,low resistance so voltage require less for glows
= 100w glows dim
formula I=V\R.

Is This Answer Correct ?

19 Yes

12 No

Question { 50556 }

how much current does 3ph. 10 hp ac motor draw.

Answer

1 Hp = 746 watts
10 Hp Motor
10*746=7460w
so 7460 w is the power drawn by 3-ph motor. and three phase
voltage is 415 voltage.

so I = P/root3*v*pf*eff
i=Wattage/1.732*415*0.8*0.85
=7460/1.732*415*0.8*0.85
=7460/489
=15.25A

Is This Answer Correct ?

78 Yes

18 No

Question { 7106 }

What is maximum load capacity of 800 VA inverter?

Answer

For load calculation we should to assuming Current power factor
If PF lies 0.8 load value= 800*0.8=640watt
If PF lies 0.6load value =800*0.6=480Watt

Is This Answer Correct ?

9 Yes

0 No

Question { 6020 }

1 KW = how many HP

Answer

1kW=1000w
1hp=746w
since
hp=1000/746=1.34hp

Is This Answer Correct ?

14 Yes

0 No