三相電加熱管

        380伏(fu)三(san)(san)相(xiang)(xiang)四線(xian)電(dian)(dian)(dian)路(lu)中，任意(yi)兩(liang)根火(huo)線(xian)之間的電(dian)(dian)(dian)壓都(dou)是380伏(fu)，任意(yi)一根火(huo)線(xian)與(yu)零線(xian)之間都(dou)可以組成(cheng)(cheng)220伏(fu)。這(zhe)個(ge)系統可以形成(cheng)(cheng)三(san)(san)種(zhong)電(dian)(dian)(dian)源(yuan)(yuan)：即單(dan)相(xiang)(xiang)220伏(fu)電(dian)(dian)(dian)源(yuan)(yuan)，單(dan)相(xiang)(xiang)380伏(fu)電(dian)(dian)(dian)源(yuan)(yuan)，三(san)(san)相(xiang)(xiang)380伏(fu)電(dian)(dian)(dian)源(yuan)(yuan)，第(di)(di) I 種(zhong)家(jia)用比較多，第(di)(di)三(san)(san)種(zhong)工(gong)廠里電(dian)(dian)(dian)機類用得(de)多，第(di)(di)二種(zhong)用得(de)少，只(zhi)有交流電(dian)(dian)(dian)焊(han)機經常用到單(dan)相(xiang)(xiang)380伏(fu)電(dian)(dian)(dian)源(yuan)(yuan)。