三相電加熱管

        380伏(fu)三相(xiang)四線電(dian)(dian)路中，任意(yi)兩根(gen)火(huo)線之間的電(dian)(dian)壓(ya)都是380伏(fu)，任意(yi)一(yi)根(gen)火(huo)線與零(ling)線之間都可以組成220伏(fu)。這個系統可以形成三種(zhong)電(dian)(dian)源：即(ji)單相(xiang)220伏(fu)電(dian)(dian)源，單相(xiang)380伏(fu)電(dian)(dian)源，三相(xiang)380伏(fu)電(dian)(dian)源，第 I 種(zhong)家(jia)用(yong)(yong)比較多，第三種(zhong)工廠(chang)里(li)電(dian)(dian)機類用(yong)(yong)得(de)多，第二種(zhong)用(yong)(yong)得(de)少(shao)，只有(you)交(jiao)流電(dian)(dian)焊機經常用(yong)(yong)到(dao)單相(xiang)380伏(fu)電(dian)(dian)源。