單相變壓器工(gong)作原(yuan)理:當變(bian)壓(ya)(ya)器(qi)(qi)一次(ci)(ci)(ci)側施加交流(liu)電(dian)壓(ya)(ya)U1,流(liu)過(guo)一次(ci)(ci)(ci)繞(rao)(rao)(rao)組的(de)電(dian)流(liu)為I1,則該電(dian)流(liu)在鐵芯中會(hui)(hui)產生交變(bian)磁(ci)(ci)通,使一次(ci)(ci)(ci)繞(rao)(rao)(rao)組和二(er)次(ci)(ci)(ci)繞(rao)(rao)(rao)組發生電(dian)磁(ci)(ci)聯系,根據電(dian)磁(ci)(ci)感應原理,交變(bian)磁(ci)(ci)通穿(chuan)過(guo)這兩個繞(rao)(rao)(rao)組就會(hui)(hui)感應出電(dian)動(dong)勢,其大(da)小與(yu)(yu)繞(rao)(rao)(rao)組匝(za)(za)數以(yi)及主磁(ci)(ci)通的(de)最大(da)值(zhi)成(cheng)正比(bi)(bi),繞(rao)(rao)(rao)組匝(za)(za)數多的(de)一側電(dian)壓(ya)(ya)高,繞(rao)(rao)(rao)組匝(za)(za)數少的(de)一側電(dian)壓(ya)(ya)低(di),當變(bian)壓(ya)(ya)器(qi)(qi)二(er)次(ci)(ci)(ci)側開路,即變(bian)壓(ya)(ya)器(qi)(qi)空載時,一二(er)次(ci)(ci)(ci)端電(dian)壓(ya)(ya)與(yu)(yu)一二(er)次(ci)(ci)(ci)繞(rao)(rao)(rao)組匝(za)(za)數成(cheng)正比(bi)(bi),變(bian)壓(ya)(ya)器(qi)(qi)起到變(bian)換電(dian)壓(ya)(ya)的(de)目的(de)。
當變(bian)壓(ya)(ya)器二次側接入負載(zai)后,在(zai)電(dian)(dian)動(dong)勢(shi)(shi)E2的(de)作(zuo)(zuo)用(yong)(yong)下(xia),將有二次電(dian)(dian)流(liu)通過,該(gai)電(dian)(dian)流(liu)產(chan)(chan)生(sheng)的(de)電(dian)(dian)動(dong)勢(shi)(shi),也將作(zuo)(zuo)用(yong)(yong)在(zai)同(tong)一(yi)(yi)鐵芯上,起到(dao)反向去磁作(zuo)(zuo)用(yong)(yong),但因(yin)主磁通取決于(yu)電(dian)(dian)源電(dian)(dian)壓(ya)(ya),而(er)U1基本保持不(bu)變(bian),故(gu)一(yi)(yi)次繞組(zu)電(dian)(dian)流(liu)必將自動(dong)增(zeng)加(jia)一(yi)(yi)個(ge)分量產(chan)(chan)生(sheng)磁動(dong)勢(shi)(shi)F1,以抵(di)消二次繞組(zu)電(dian)(dian)流(liu)所產(chan)(chan)生(sheng)的(de)磁動(dong)勢(shi)(shi)F2,在(zai)一(yi)(yi)二次繞組(zu)電(dian)(dian)流(liu)L1、L2作(zuo)(zuo)用(yong)(yong)下(xia),作(zuo)(zuo)用(yong)(yong)在(zai)鐵芯上的(de)總磁動(dong)勢(shi)(shi)(不(bu)計空載(zai)電(dian)(dian)流(liu)I0),F1+F2=0,
由于F1=I1N1,F2=I2N2,故
I1N1+I2N2=0,由式可知,I1和(he)I2同相(xiang),所以
I1/I2=N2/N1=1/K
由式可知,一(yi)二(er)(er)(er)次(ci)電流(liu)比與一(yi)二(er)(er)(er)次(ci)電壓(ya)(ya)比互(hu)為倒數,變(bian)壓(ya)(ya)器一(yi)二(er)(er)(er)次(ci)繞組(zu)功(gong)率(lv)基本不變(bian),(因(yin)變(bian)壓(ya)(ya)器自身損耗(hao)較其傳(chuan)輸功(gong)率(lv)相對較小(xiao)),二(er)(er)(er)次(ci)繞組(zu)電流(liu)I2的大(da)小(xiao)取決于負載(zai)的需要,所(suo)以一(yi)次(ci)繞組(zu)電流(liu)I1的大(da)小(xiao)也取決于負載(zai)的需要,變(bian)壓(ya)(ya)器起(qi)到了功(gong)率(lv)傳(chuan)遞的作用。
所謂變壓(ya)(ya)器(qi)(qi)就是(shi)(shi)要改變電(dian)(dian)(dian)壓(ya)(ya),一般發電(dian)(dian)(dian)機(ji)輸(shu)出(chu)為(wei)三(san)相(xiang)(xiang)(xiang)(xiang)(xiang)正弦交(jiao)流(liu)電(dian)(dian)(dian),分(fen)(fen)為(wei)U相(xiang)(xiang)(xiang)(xiang)(xiang)、V相(xiang)(xiang)(xiang)(xiang)(xiang)、W相(xiang)(xiang)(xiang)(xiang)(xiang)。發電(dian)(dian)(dian)機(ji)分(fen)(fen)三(san)角形(xing)連接(jie)和星型連接(jie):三(san)角形(xing)連接(jie)就是(shi)(shi)將三(san)項(xiang)首尾(wei)連接(jie)起(qi)來輸(shu)出(chu)三(san)條線幾十所謂的(de)三(san)相(xiang)(xiang)(xiang)(xiang)(xiang)間(jian)的(de)電(dian)(dian)(dian)壓(ya)(ya)有效值為(wei)380V,星型是(shi)(shi)將三(san)星的(de)首或尾(wei)連接(jie)起(qi)來輸(shu)出(chu)四(si)條線分(fen)(fen)別為(wei)三(san)相(xiang)(xiang)(xiang)(xiang)(xiang)和地(di)線,而(er)三(san)相(xiang)(xiang)(xiang)(xiang)(xiang)的(de)任意一相(xiang)(xiang)(xiang)(xiang)(xiang)和地(di)線的(de)連接(jie)稱為(wei)單(dan)(dan)項(xiang)電(dian)(dian)(dian)有效值為(wei)220V用(yong)于單(dan)(dan)相(xiang)(xiang)(xiang)(xiang)(xiang)電(dian)(dian)(dian)的(de)變壓(ya)(ya)器(qi)(qi)稱為(wei)單(dan)(dan)向(xiang)變壓(ya)(ya)器(qi)(qi),而(er)連接(jie)于單(dan)(dan)相(xiang)(xiang)(xiang)(xiang)(xiang)變壓(ya)(ya)器(qi)(qi)次級的(de)負載稱為(wei)單(dan)(dan)相(xiang)(xiang)(xiang)(xiang)(xiang)負荷。