This preview shows pages 1–9. Sign up to view the full content.
This preview has intentionally blurred sections. Sign up to view the full version.
View Full DocumentThis preview has intentionally blurred sections. Sign up to view the full version.
View Full DocumentThis preview has intentionally blurred sections. Sign up to view the full version.
View Full DocumentThis preview has intentionally blurred sections. Sign up to view the full version.
View Full Document
Unformatted text preview: ELECTRICAL ENGINEERING DEPARTMENT
California Polytechnic State University BB 255 Assignment #8 Problem #1 At a location in USA, it is necessary to supply 300 KW of 50—Hz power. The only
power source available operate at 60Hz. It is decided to generate the power by
means of motor—generator set consisting of synchronous motor driving a
synchronous generator. How many poles should each of the two machines have in
order to convert 60—HZ t0 50Hz power? Problem #2 A 2400V, IOOOKVA, 0.8—PF—lagging, 60—Hz, 4poles, delta—connected synchronous generator has a synchronous reactance of 1.1 Ohms and an armature resistance of 0.15 Ohms. At 60Hz, its friction and windage losses are 20 KW, and its core losses are 15 KW. The ﬁeld circuit is adjustable over the range from 20 to 200 Q. The OCC oft is generator i sho‘ m in Figure P5=l, page 338 {4th edition) or Figure P6l, page 353 (3rd edition). a. How much ﬁeld current is required to make the no—load terminal voltage equal
to 2.4 KV? b. What is the internal generated voltage of this machine at rated load
conditions? 0. How much ﬁeld current is required to make the terminal voltage equal to 2400
V when the generator is running at rated conditions? (1. ' How much power and torque must the generator’s prime mover be capable of supplying?
Problem #3 Assume that the ﬁeld current of the generator of problem 2 has been adjusted to a
value of 4.5 A.
a. What will the terminal voltage of this generator be if it is connected to a delta
connected load with an impedance of 24145°Q ?
1). Sketch the phasor diagram of this generator.
0. Now assume that another identical deltaconnected load is to be paralleled
with the ﬁrst one. What happens to the phasor diagram of the generator?
“W hat is the new terminal voltage after the load has been added?
0 XIILn+m 141.. .+. .4 .4 m' ] 4 '4— .. _' '_ I y 1...
vv ucu LLLhSL [)6 (110116 LG ICStOIC thC LCuulﬁai voltage LO 1L3 Oﬂgiﬁar 'vaiuﬁ.’ p: or Problem #4 A 480V, 60HZ, 4—p01e, Y—connected synchronous generator rated at 300«
KVA and 0.9 PF lagging. Its armature resistance is 0.02 Ohms The core losses
of this machine at rated conditions are 7 KW, and the friction and Windage
losses are 8 KW. The open and shortcircuit characteristics are shown in the Errata Sheet under error 7. a. What is the saturated synchronous reactance of this generator at rated
armature current? b. What is the unsaturated synchronous reactance of this generator at rated
armature current? c. What is the internal generated voltage of this generator under rated
conditions? d. What field current does this generator require to operate at the rated
voltage, current, and power factor? e. What is the voltage regulation of this generator at the rated current and
power factor? f. If this generator is operating at the rated conditions and the load is
suddenly removed, what will the terminal voltage be? g. What are the electrical losses of this generator at rated conditions? h. If this generator is operating at the rated conditions, what input torque
must be applied to the shaft? i. Determine the efﬁciency of the generator under rated conditions. 2m.
__
«r a: m a?
Hun . mpg __ Lw a.
(w a ma... M, M
ode
__ (5
r __ mm 0
1% mm o : I.
M0 e 5 MN. _ = __ mam commaquU muamcmmcw m w E .mmm .oZ @ﬁﬂgkﬁmﬁgmm mm Eﬁgineefs Computation Pad N0. 9'37 811E 2%? E31135 QTLER‘E 2402: V 50 #2: )(5 2’ H .2 1000 {CW} 4..de9 2“ :6'15JL 0 8p; A 4a.”?! = 204:“)
gm: 6th Ea. T745 L Ea(Pq, +jX5)
.3 24mg." + I37Z:E‘f¥7a(o.15 +} U)
z 25)! £5: \/ 2 \ —3' 1
: 3004.303?) 69.15,)” + 15 +20
:3 8143 7 KW
7",, g. 3553700 :— un’ié Mm
701 2514:5623 Engineer’s, Computaé‘ion Pad Na. 93'? 8%1E é? EETﬂEﬂTLERGJ 11/2. 4) (3.57 :. 2217.5 /"”’55 \/ III—— :5 —« fmkcgwj XS C) [aacis I “ I. I
w (pan/4109] O V l .279" _..———— l2— L‘i‘é °
0.2; an +/2 45 I 2139/
1;. V4) 2’," 2.30éZ90 fag, Via/$5 Hrs:3 \‘J a :41) 5 I _........
__._..... Ema. commaﬁrcuw mummcﬁcw w W. a E .03 gmmﬁmmﬁm mm g
g
H  mmmmgm_._,_w_m
a
i
I
! NO. 93? 811E? é? SSTﬂEIQTiEW) Engineer‘s Computaiicn Pad E £ 0“? I’Hfj
Pa W? «9152—
4—7M/c. Boo,va 43:0,: :7 KM a) ﬁnd X5 “hawk”; 3:43. 
Smi' IQ = 350/”? ._. 3a.? F}
mks ﬁxgfa
550% sec: I; :2 0.3;}.
From 0C6; a. :: 650V
LL
z'z X5 = 7650 :2 [0452,91‘
*4 gage8) /
lo) $V0‘M A'W'JQP [like Ea =é50 V
LL
X5 : 65o ’ J; L
mm 37350.9) 0‘" A”
C) £43 at *”4(P€LHXS)
_.; 1.775} M 7&4; rﬁ'g‘f A
I /L— 1 vw (a
35,3e5 '39 a“) 1'" I (PH/rt? r] r/v1 a \/
batL :43 L97 7/ = 7913 v l mmimmm, . _ Red. = $7414 Open Circuit Characteristic 1200 1100 1000 Opencircuit voltage, V
an
8
I 400 L 300 200 100 00 0.! 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 [.1 1.2 1.3 1.4 L5
FieidcurrenLA
(a) Shari Circuit Characteristic
1600 1200 5.
5
I § Armatm'e current, A 0 i ‘  i L
n n I: n u
u . . u.u mu Field current, A
(b) }
.__.
m
m 05? 1")
2)
cm
(7)
... . (3
":l
m
( RD
"U
93
00
CD
93
5.]
:J
"U
F:
O
E
('D
B
c3‘
,_._.
‘r—‘
E
5'3
5
:
(D
rs
(D
53.
w
1!
m
3
O
(‘D
a.
F3
O
00
“{O
S}
:3
:1.
c—h
LT‘
(D
m
‘4
D
E
O
:5
O
5:
m 10. Page 470, Problem 7—20 ((1), the holding the inﬁnite bus is 460V. Engineer‘s Cornpu‘iaiicrr‘: Pad NO. 93? 811E é? §§TﬁE§E3TLER® ...
View
Full
Document
This homework help was uploaded on 04/07/2008 for the course EE 255 taught by Professor Shaban during the Fall '05 term at Cal Poly.
 Fall '05
 Shaban

Click to edit the document details