1. In a ckt. We are giving voltage of 50 Hz as well as 60.
then what will be the resultant
frequency.
less than 50 more
than 60 in between 50 & 60 none
according to our conclusion answer will be none because if
we apply two frequency component
resultant 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..
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.
8. In an incandescent lamp
(a) luminous intensity is more than non-luminous intensity
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 ?, ? is
(a) Avg value, (b) Rms value, (c) Maximum value
Ans: (a)
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)
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)
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)
27. Insulation used in transformer ___________leakage flux.
(a) increases, (b) decreases Ans: (b)
28.After rain what happens to Insulator (a) break-down
strength of Insulator decreases, (b)Arch
length reduces,
Ans: (b)
29.Diversity factor helps to . . . .(what ?)
[Read diversity factor, load factor, Reserve capacity factor
in depth, with calculation]
30. Why capacitance is shown as a Shunt element in analysis
of transmission line
(a) it is between Conductor & earth, (b) because
Admittance is used for calculation of
capacitive reactance
Ans: (a)
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)
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]
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
34. In electro-dynamometer A'meter & wattmeter the type of
scale is Ans:Non-uniform
35. For the same current carrying capacity corona loss of
ACSR will be ________than copper
conductor. (a) more, (b) less, (c) equal
Ans:(b)
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.
Ans: No change at all
37. Read about surge impendence of over-head and
under-ground cable, Surge impedence
formula = sqrt(L/C)
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.
