三相電加熱管

        380伏三(san)(san)相(xiang)(xiang)(xiang)四(si)線(xian)電(dian)(dian)(dian)路中，任意兩根火(huo)線(xian)之(zhi)間的(de)電(dian)(dian)(dian)壓(ya)都(dou)是380伏，任意一根火(huo)線(xian)與零(ling)線(xian)之(zhi)間都(dou)可(ke)以組成220伏。這(zhe)個系統可(ke)以形成三(san)(san)種(zhong)電(dian)(dian)(dian)源(yuan)：即單相(xiang)(xiang)(xiang)220伏電(dian)(dian)(dian)源(yuan)，單相(xiang)(xiang)(xiang)380伏電(dian)(dian)(dian)源(yuan)，三(san)(san)相(xiang)(xiang)(xiang)380伏電(dian)(dian)(dian)源(yuan)，第(di) I 種(zhong)家用比較多(duo)，第(di)三(san)(san)種(zhong)工廠里電(dian)(dian)(dian)機類用得(de)多(duo)，第(di)二種(zhong)用得(de)少，只(zhi)有交(jiao)流電(dian)(dian)(dian)焊機經常(chang)用到單相(xiang)(xiang)(xiang)380伏電(dian)(dian)(dian)源(yuan)。