suneetha.p.s


{ City } kochi
< Country > india
* Profession * final year electrical student
User No # 20959
Total Questions Posted # 4
Total Answers Posted # 8

Total Answers Posted for My Questions # 12
Total Views for My Questions # 29217

Users Marked my Answers as Correct # 227
Users Marked my Answers as Wrong # 99
Questions / { suneetha.p.s }
Questions Answers Category Views Company eMail

difference b/w semiconductor and insulator

 5 Electrical Engineering 8524

difference b/w semiconductor and dielectric

 2 Electrical Engineering 12519

why induction generators are used in wind mills.why cant synchronous generators b used??

 2 Electrical Engineering 3932

is it necessarry to charge the battery of ups always??

 3 Electrical Engineering 4242



Answers / { suneetha.p.s }

Question { NTPC, 9708 }

What are eddy current and define rms value?


Answer

EDDY CURRENTS:
when a conductor kept in magnetic field
rotates an emf is induced in it.This emf sets up large
current in the body of the core bcoz of its low resistance
This current acc to lenz's law opposes the cause that is
producing it.This current is known as eddy current loss.

RMS:-
RMS of an a.c is that steady state current
(d.c) which when flowing thgh a given resistance for a givn
time produces the same heating effect as produced by the
a.c when flowing thgh the same resistance for the same time
all a.c meters are caliberated to read rms
value

Is This Answer Correct ?    33 Yes 3 No

Question { GE, 66638 }

lllg,llg,ll,lg,lll which fault is severe and why?


Answer

line-grnd fault is most severe fault.It is seen that usin
formula lg current is almost 1.5 times greater than three
phase fault(symmetrical fault)

Is This Answer Correct ?    14 Yes 61 No


Question { 21141 }

WHY TRANSFORMERS ARE RATED IN 11KV 22KV 33KV Instead off
10kv 20kv 30kv


Answer

this is due to form factor
rms value of induced emf= form factor * average value

form factor is calculated as 1.11
so the ratings are usually expressed in multiples of 11

Is This Answer Correct ?    72 Yes 11 No

Question { Voltas, 17459 }

How can we calculate the rating of capacitor bank to be
connected for a particular load(ex.100kw)to improve the
power factor from 0.8 to 0.9?


Answer

The rating of capacitor bank is in kvar.Kvar rating can be
found out by power traingle.
active power=100kw
let the angles corresponding to power factors .8 and .9 be
A1 and A2 respectively
then reactive power required to improve the power factor
=100sin(A1)-100sin(A2)

Is This Answer Correct ?    18 Yes 9 No

Question { Voltas, 12950 }

when neutral will carry the current?what could be the
magnitude?


Answer

neutral will carry current only during unbalanced or faulty
condition.During balanced condition current through neutral
is zero(Ia+Ib+Ic=0).Magnitude of neutral current depends on
the fault current magnitude.

Is This Answer Correct ?    36 Yes 3 No

Question { BARC, 11025 }

is there any difference between protection C.T and
measuring C.T?if yes then what is the difference?


Answer

ct used for protection has to carry full load current and
fault current.ct core shudnt get saturated while carryin
fault current.So the ct used for protection shud hav high
saturation factor.But ct used for measuring shud hav high
accuracy

Is This Answer Correct ?    17 Yes 4 No

Question { Birla, 18226 }

Why the transformers are rated in kva?


Answer

in oder machines lik motors also core loss is prop to
voltage n cu loss is prop to current..but dey are rated in
kw nly...y s t so???

Is This Answer Correct ?    6 Yes 4 No

Question { Engineers India Limited, 16329 }

how the 12 pulse rectifier is made?


Answer

12 pulse rectifier is made of two 6 pulse rectifiers in
which 1 rect s connected in star n oder in delta.The input
side is connected in parallel and the o/p side in series

Is This Answer Correct ?    31 Yes 4 No