電工技術(shù)基礎(chǔ)5三相電路

A =2E=2EsinA?A?SY?Z?CwNBXAAX繞組并以w的速度旋轉(zhuǎn)。三個(gè)EmsinwteBEmsinwt-)Emsinwt-sin(wt+120))m wt

0°120240360=E—-

C

B

BA+BA

+E= CBCAAeZXNCYeBBC

X N

C

A CA uA= uB=eBuC=

BBBB U =UP— —-

C CU =UP—

Bu

uA uuu uBBuCCAB CABCABA= A=AA

BB+BB=ABAB

-

BC-= BC-=CC

C - CC C3倍，3倍，

Bpl

=3U ZZZ ZZZ N uAu NCZCZuB

BC 、 BC

*相電流=線電流A= A

Z

=I

IC=

IN=lp=lp

AZCNCZZUBCUBCBAB=AAZBCZZAIZNZUBCCCUBICZBIlIl=Ip=pBPCP—-N

=UP— =U

Z—

—-

=UZU

—- C C

p— ZUYZ3j4W，

=380=33A設(shè)33A

=220—0

Z=3+j4=5—53.1B =220—-120B

I=

=

UC =220—120

=44—-53.1

=44—-53.1 =44—-173.1 =44—66.9如：ZAZBZCZj 則： =A=

=IA+IB+

CC

II=I+I+I=0NABCeeeAAZcZZeBBC

eAe

B C

AC

ZZZZZZZZ AANBC= =UP 允許接絲也不允許接刀閘。A

iBC C

A

= AB

AB

ZABCCZ

BI= UCAI=ZCAZCA

流I流IC

BCA

iA

BiBBC C

效值相等，相位互差120。有效值為：IAB

IP

ZAA

=Ul— =-=-

3\ —-3

U U

- -3=3=B

—-

IA

—- 3 3

A

BiBBC C

§=— P=P=3UpIpcos

+B

+C

j由負(fù)載Ul=3UP=3UlIP=3UlIlcos\

Il=I3Il I3有功功率：P=無(wú)功功率：Q=視在功率：S=

UlIlcosjUlIlsinjUlIl 33p =380=33p292+ 292+

Il =Ip=3292+P=3UlIlcos3292+=3200W=

·380 負(fù)載三角形聯(lián)接時(shí)，UpUl292+ 292+

33292+ =3Ip=33292+P=3UlIlcosj=3200W=

Up=220V,Ip=6.1A,Il=6.1A,Up=220V,Ip=6.1A,Il=10.5A,例2.線電壓Ul為380V的三相電源上接有兩組對(duì)稱三抗ZΔ=36.3/37o?;另一組是星形聯(lián)接的電阻性負(fù)載，A C CR

設(shè)線電壓UAB=3800o

.

=380— =10.47—-37o

DD

C C

AI I I =IY

=220—-

II

（2）IAD

比 比

3—-37o-30o=18.13—-67oI=

C C

AI I AI=38—-46.7oACCB

P=PD+Y=UlIADcosjD+UlIAY=3·380·18.13·0.8+3·380·=24026W?AA CZZZZZZ ZZZZZZN l=l

I=

lP lP