三相電加熱管

        380伏三(san)(san)相(xiang)四線(xian)(xian)電(dian)(dian)路中(zhong)，任(ren)意兩(liang)根火(huo)線(xian)(xian)之(zhi)間的電(dian)(dian)壓都是380伏，任(ren)意一根火(huo)線(xian)(xian)與零(ling)線(xian)(xian)之(zhi)間都可(ke)以組成220伏。這個系統可(ke)以形成三(san)(san)種(zhong)電(dian)(dian)源：即單相(xiang)220伏電(dian)(dian)源，單相(xiang)380伏電(dian)(dian)源，三(san)(san)相(xiang)380伏電(dian)(dian)源，第(di) I 種(zhong)家(jia)用比較多，第(di)三(san)(san)種(zhong)工廠(chang)里電(dian)(dian)機類(lei)用得多，第(di)二種(zhong)用得少，只有交流電(dian)(dian)焊(han)機經常用到(dao)單相(xiang)380伏電(dian)(dian)源。