380伏三(san)相四線(xian)電(dian)(dian)路中,任意兩根(gen)火線(xian)之間的電(dian)(dian)壓都是380伏,任意一根(gen)火線(xian)與零線(xian)之間都可(ke)以組(zu)成220伏。這個(ge)系統可(ke)以形成三(san)種(zhong)電(dian)(dian)源(yuan):即(ji)單(dan)相220伏電(dian)(dian)源(yuan),單(dan)相380伏電(dian)(dian)源(yuan),三(san)相380伏電(dian)(dian)源(yuan),第 I 種(zhong)家用比較多(duo),第三(san)種(zhong)工(gong)廠(chang)里(li)電(dian)(dian)機類用得(de)多(duo),第二種(zhong)用得(de)少,只有(you)交流電(dian)(dian)焊機經常用到(dao)單(dan)相380伏電(dian)(dian)源(yuan)。