ABB
- Placement Paper - 2 May 2004 - Vadodra
1)in a ckt. We r giving voltage of 50 Hz as well as 60. then what will
be the resultant frequency.
(a)less
than 50 (b)more than 60(c)in between 50 & 60
(d)none���.according
to our conclusion answer will be none because if we apply two frequency
component resultatnt frequency we can not say with such an ease.U should
confirm the answer
2.In
a ckt a single resistor is connected across a
d.c.
source, what will be the effect on current in first resistor if we
connect one more resistance in parallel with earlier one�.
Answer..
no change since it is a parallel combination.
3.why
we don,t like flashover in transmission line (t-line)-
(a
) it may create earth fault(b )it reduces the life of insulator�..
Read
something about flashover & puncture.
4.total
no of strands in a acsr conductor is 81, then what is
the no. of conductor in its outer layer�.(a)36 (b)18 (c)24��.Also
read some more on acsr.
5.Two
questions based on p.u. calculation like , p.u. calculation is given
with respect to some old base and u have to calculate it with reference
to new base.
(new
resistance/old)=(mva new /mva old)*(old voltage/new voltage)2.
Other
question is based upon transfer of p.u calculation in transformer i.e.
how base changes when we we move from primary to secondary or like
wise.read some more on p.u calculation.
6.which
table is referred for sag calculation-
(a)stringing
chart��answer
7.in
a R-L ckt a ac voltage is applied , such that instantaneous power is
negative for 2ms, then what will be the power factor.
(a)
9 deg, (b) 18 deg, (c) 36 Deg���..(I don�t know the correct ans)
8.
In an incandescent lamp
(a)
luminous intensity is more than non-luminous intensity
(b)
,,
,,
,, less ,,
,,
,,
Ans:
Since efficiency is less than 100%, hence ans is (b), u should confirm
it further.
9.
In which motor no-load to full-load diff. is lowest
(a)
series motor, (b) shunt motor, (c) Compound motor
Ans:
(b)
10.
In a 60Hz induction motor full load speed is 850 rpm then what is the
Synchronous speed. (a) 900 rpm, (b) 950 rpm, (c) 1600
rpm������..Ans: (a)
11.
A sync. Motor is running at synch. Speed, if al of sudden D.C.
excitation is removed, then
(a)
it will rotate at slip speed, (b) it will stop, (c) it will continue to
rotate at sync. Speed
Ans:
(a), because actually it will acts as Induction
motor.
12.
A transmission line is designed for 50Hz, 440KV. If we want to transfer
power at 60Hz, 440 KV, then the power transfer capability will
(a)
decrease, (b) Increase, (c)None
Ans:
(a) �as P=( |Vt|
|Ef| sin (delta) ) / X, where
(delta) is torque angle.
13.
Increased rotor resistance in rotor ckt of induction motor is related
with
(a)
high starting torque, (b) more speed variation,�������Ans:
(a)
14.
In the formulae E = 4.44 f N Ф, Ф is
(a)
Avg value, (b) Rms value, (c) Maximum value�������Ans:
(a)�[confirm it]
15.
Voltage & current in a ckt is given by V= V1+j V2 and I= I1 +j I2,
then rms power is
��.(refer
book
by Edministrator on NETWORK ..)
16.
Input impedence of MOSFET is
(a)
more than BJT��..(Ans)
17,
18. Remember truth table of AND, NOR,
NAND
,
OR
, EX-OR ETC�
19.
Conversion of Binary number into Equivalent decimal No.
20.
Megger is used for the measurement of (a) Insulation
resistance, (b) Conductor resistance����.Ans: (a)
21.
Form factor for sinusoidal as well as DC
22.
Formulae of Regulation (Vs- Vr)* 100/ Vr, then
transmission line is
(a)
short transmission line, (b) long, (c) medium������.Ans: (a)
23.
Improvement in power factor reduces
(a)
power consumed by consumer, (b) power
generation, (c) both a & b���..Ans: (c)
[Confirm
it]
24.
Read about field test of Series Motor�
25.
No-load test for Synchronous motor, the graph is drawn
(a)
stator open ckt emf Vs field
current�������������(Ans: a)
<!--[if
!supLists]-->26.
An AC voltage of 50Hz is impressed in a resistive ckt, the
oscillating power has a frequency (a) 50 Hz, (b) 100, (c) no oscillating
power is there in resistive ckt��Ans: (a)<!--[endif]-->
<!--[if
!supLists]-->27.
Insulation used in transformer ___________leakage flux.<!--[endif]-->
<!--[if
!supLists]-->(a)
increases, (b) decreases����Ans: (b) <!--[endif]-->
28.After
rain what happens to Insulator (a) break-down strength of Insulator
decreases, (b)Arch length reduces, ���.Ans: (b)�..[Confirm it]
29.Diversity
factor helps to ����(what ?)
[Read
diversity factor, load factor, Reserve capacity factor in depth, with
calculation]
<!--[if
!supLists]-->30.
Why capacitance is shown as a Shunt element in analysis of
transmission line <!--[endif]-->
<!--[if
!supLists]-->(a)
it is between Conductor & earth, (b) because
Admittance is used for calculation of capacitive
reactance��������Ans: (a)<!--[endif]-->
<!--[if
!supLists]-->31.
B-R-Y sequence is followed in three phase system, if phase
voltage in B-phase is Vm sin 100, then the phase
voltage in R-phase would be (a) Vm sin (-20)��Ans:(a)<!--[endif]-->
<!--[if
!supLists]-->32.
In a particular ckt I = Im Sin (wt -270) and V = Vm Sin
wt, then type of ckt is (a) pure resistive ckt������..[Ans]<!--[endif]-->
<!--[if
!supLists]-->33.
In a L-R ckt energy lost = 2000 W, energy conserved =
500W, then what is the time constant���..Ans: time constant = L/R
= 0.5<!--[endif]-->
<!--[if
!supLists]-->34.
In electro-dynamometer A�meter & wattmeter the type
of scale is �Ans:Non-uniform<!--[endif]-->
<!--[if
!supLists]-->35.
For the same current carrying capacity corona loss of ACSR
will be ________than copper conductor. (a) more, (b) less, (c) equal�Ans:(b)<!--[endif]-->
<!--[if
!supLists]-->36.
A R-C ckt , supplied with DC, a bulb is connected across
the Capacitor, then what happens to the illumination, if we change the
capacitance.<!--[endif]-->
Ans:
No change at all
<!--[if
!supLists]-->37.
Read about surge impendence of over-head and under-ground
cable, Surge impedence formula = sqrt(L/C)<!--[endif]-->
*****[N.B]
We are not mentioning the options in sequence, and do not think that ans
for the most questions is option (a). Read all options very carefully as
all are very close to each other.
QUANTITATIVE
PAPER + PCM paper
45
Questions ---------45 minutes
1.
About 10 quanti questions ( based on Mixture, Work etc. of very easy
type)
2.
What is GDP ?
3.
Vector algebra, codition for Co-planer vector etc.
4.
Gravitation, geo-synchronous satellite( it�s hight, orbit , radius
etc.), escape velocity, how g (gravitational accln) varies, about
gravitational potential.
5. Basic electricity and Magnetism----Biot-savart law, current
carrying conductor properties.
6.
Nuclear physics, Bohr�s constant, and Other theories related .
7.
Problem based on VIBGYOR , how wave length and frequency is varying.
8. Questions based on Plank�s Theory, E =hv
9.
V=u + at , V2=u2 + 2as and W = mgh
questions
based on above theory
10.
Faraday�s laws of electrolysis, m = Zit
11.
Heat conduction problem.
12.
Co lour-coding of resistor (BBROYGBVGW)
13.
How velocity of light changes in different medium while frequency remain
unchanged.
14.
statistics , calculation of mode, co-efficient regression (3-4
Questions)
15.
f(x) = Sin x +
Cos
x, find the maximum value of the function��.Ans: sqrt (2)
16.
Formulae for parallel plate capacitor and force between plates.
