三相電加熱管

        380伏三(san)相(xiang)四線(xian)電(dian)(dian)(dian)路中，任意兩根(gen)火(huo)線(xian)之間(jian)的(de)電(dian)(dian)(dian)壓(ya)都是380伏，任意一根(gen)火(huo)線(xian)與零線(xian)之間(jian)都可以(yi)組(zu)成220伏。這個系統(tong)可以(yi)形(xing)成三(san)種(zhong)電(dian)(dian)(dian)源(yuan)：即單(dan)相(xiang)220伏電(dian)(dian)(dian)源(yuan)，單(dan)相(xiang)380伏電(dian)(dian)(dian)源(yuan)，三(san)相(xiang)380伏電(dian)(dian)(dian)源(yuan)，第 I 種(zhong)家用比較多，第三(san)種(zhong)工廠里電(dian)(dian)(dian)機類用得多，第二(er)種(zhong)用得少(shao)，只有(you)交流電(dian)(dian)(dian)焊機經常用到單(dan)相(xiang)380伏電(dian)(dian)(dian)源(yuan)。