外文翻译
外文翻译
DCGENENRATORS
1INTRODUCTION
Forallpracticalpurposesthedirectcurre
tge
eratoriso
lyusedforspecialapplicatio
sa
dlocaldcpowerge
eratio
Thislimitatio
isduetothecommutatorrequiredtorectifythei
ter
alge
eratedacvoltagetherebymaki
glargescaledcpowerge
erators
otfeasible
Co
seque
tlyallelectricale
ergyproducedcommerciallyisge
erateda
ddistributedi
theformofthreephaseacpowerTheuseofsolidstateco
verters
owadaysmakesco
versio
todceco
omicalHowevertheoperati
gcharacteristicsofdcge
eratorsarestillimporta
tbecausemostco
ceptsca
beappliedtoallothermachi
es
2FIELDWINDINGCONNECTIONS
Thege
eralarra
geme
tofbrushesa
dfieldwi
di
gforafourpolemachi
eisasshow
i
Fig1Thefourbrushesrideo
thecommutatorThepositivebrusherareco
ectedtotermi
alA1whilethe
egativebrushesareco
ectedtotermi
alA2ofthemachi
eAsi
dicatedi
thesketchthebrushesarepositio
edapproximatelymidwayu
derthepolesTheymakeco
tactwithcoilsthathavelittleor
oEMFi
ducedi
themsi
cetheirsidesaresituatedbetwee
poles
Figure1Sketchoffourpoledcmatchi
e
Thefourexcitatio
orfieldpolesareusuallyjoi
edi
seriesa
dtheire
dsbroughtouttotermi
alsmarkedF1a
dF2Theyareco
ectedsuchthattheyproduce
ortha
dsouthpolesalter
ately
Thetypeofdcge
eratorischaracterizedbythema
eri
whichthefield
1
f西安交通大学城市学院本科生毕业设计（论文）
excitatio
isprovidedI
ge
eralthemethodemployedtoco
ectthefielda
darmaturewi
di
gsfallsi
tothefollowi
ggroupsseeFig2
Figure2Fieldco
ectio
sfordcge
eratorsaseparatelyexcitedge
eratorbselfexcitedshu
tge
eratorcseriesge
eratordcompou
dge
eratorshortshu
tco
ectio
ecompou
dge
eratorlo
gshu
tco
ectio
Theshu
tfieldco
tai
sma
ytur
sofrelativelyfi
ewirea
dcarriesacomparativelysmallcurre
to
lyafewperce
tofratedcurre
tTheseriesfieldwi
di
go
theotherha
dhasfewtur
sofheavywiresi
ceitisi
serieswiththearmaturea
dthereforecarriestheloadcurre
t
Beforediscussi
gthedcge
eratortermi
alcharacteristicsletusexami
etherelatio
shipbetwee
thege
eratedvoltagea
dexcitatio
curre
tofage
eratoro
oloadThege
eratedEMFisproportio
altoboththefluxperpolea
dthespeedatwhichthege
eratorisdrive
EGk
Byholdi
gthespeedco
sta
titca
beshow
theEGdepe
dsdirectlyo
thefluxTotestthisdepe
de
cyo
actualge
eratorsis
otverypracticalasiti
volvesamag
eticfluxmeasureme
tThefluxisproducedbytheamperetur
softhefieldcoilsi
tur
thefluxmustdepe
do
theamou
toffieldcurre
tflowi
gsi
cethe
umberoftur
so
thefieldwi
di
gisco
sta
tThisrelatio
shipis
otli
earbecauseofmag
eticsaturatio
afterthefieldcurre
treachesacertai
valr