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Unformatted text preview: “.12 The three loads in the circuit seen in Fig. P1022 are
described as follows: Load 1 is absorbing 7.5 kw
and zson VAR; load 2 is absorbing 10 IrVA at a 11.23 pf lead; load 3 is :1 12.5411 resistor in parallel
with an inductor that has a reactance of 5D 11. a} Calculate the average power and the magnetic
ing reactive power delivered by each source if
1v£1 = ‘qu2 = sang 1trotInns}. b} Check your calculations by showing your results
are consistent with the requirements Epikv = 2P1]:
Egav = 29“ Fiqurl ”0.22 111.24 The three loads in the circuit shown in Fig. P1ﬂ24
are s, = 5 + 1125 We, as = 6.25 + as kve,
andSa = s +,rn ave
a] Calculate the complex power associated with IIEl] voltage source, V3.1 and V31. b] 1«Fecrify that the total real and reactive power
delivered by the sources equals the total real
and reactive power absorbed by the network. Film: P10. 2i 10.29 a] Find the average power dissipated in the line in
Fig. Haze. b] Find the capacitive reactance that when con—
nected in parallel with the load will make the
load look purely resistive c} What is the equivalent impedance of the load
in {b}?
d] Find the average power dissipated in the line when the capacitive reactance is connected
acrnssthe load. e] Express the power loss in {d} as a percentage of
the power loss found in [a]. F'iuurl Hill!
I so I3 11 '
11D ﬂ
4551!]:
Vfrcns] i911“ Swrm—+—Lhe—+—Load “.32 A factory has an electrical load of 1600 kw at a lag
ging power factor of as. An additional variable
power factor load is to be added to the factory. The
new load will add 32D kw to the real power load of the factory The power factor of the added load is to
be adjusted so that the overall power factor of the factory is D36 laging. a} Specify the reactive power associated with the
added load. b} Does the added load absorb or deliver magnet
izing vars?
c] what is the power factor of the additional load? d} Assume that the voltage at the input to the fac
tory is 2410!] V {ﬁns}. what is the rms magnitude of the current into the factory before the vari—
able power tactor load is added? e} what is the rms magnitude of the current into
the factory after the variable power factor load
has been added? “.47 The peak amplitude of the sinusoidal voltage PEEL
HULTJEH I'M5 source in the circuit shown in Fig. P104? is 130 V, and its frequency.r is XIII radfs. The load resistor
can be varied from D to 40]) ﬂ, and the load capac— itor can be varied from 0.1 pF to {1.5 pF. a} Calculate the average power delivered to the
load when Ra = 211K] [1 and CE = (1.2 pF. b} Determine the settings of 1%.,I and C... that will
result in the most average power being transr ferred to En. c] What is the most average power in {b}? Is it
greater than the power in [a]? d} It there are no constraints on .i'tﬂ and Ca, what is the maximum average power that can be deliv~
ered to a load? e} What are the values of Ru and Ca tor the condi—
tion of {d}? I} Is the average power calculated in {:1} larger
than that calculated in {c}? Figure P111.“ IS In 13.6 H The variable resistor in the circuit shown in
Fig. P1l].49 is adjusted until the average power it
absorbs is maximum. a} Find R.
b} Find the maximum average power. 4;) Find a resistor in Appendix H that would have
the most average power delivered to it. Fiym PillW
5 ﬂ —j18 ﬂ. sun Iﬁﬂﬂ 111.5“ The variable resistor R5 in the circuit shown in Fig. P1D.5ﬂ is adjusted until maximtuu average
power is delivered to R5. a) What is the value of R, in ohms?
b] Calculate the average power delivered to R5. c} If RE is replaced with a variable impedance 39,
what is the maximum average power that can be delivered to 2,]? d] In (o), what peroeutage of the Circuit’s devel—
oped power is delivered to the load 25'? Fiﬂﬂl Pithsﬂ E
10 511 ...
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 Spring '11
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