三相電加熱管

        380伏三相(xiang)四線電(dian)(dian)路中，任意兩根火(huo)線之(zhi)間的(de)電(dian)(dian)壓都是380伏，任意一根火(huo)線與零線之(zhi)間都可以組成(cheng)220伏。這(zhe)個系(xi)統(tong)可以形成(cheng)三種電(dian)(dian)源：即單相(xiang)220伏電(dian)(dian)源，單相(xiang)380伏電(dian)(dian)源，三相(xiang)380伏電(dian)(dian)源，第 I 種家用(yong)比(bi)較多，第三種工廠里電(dian)(dian)機類用(yong)得(de)(de)多，第二(er)種用(yong)得(de)(de)少，只有(you)交流電(dian)(dian)焊機經常用(yong)到單相(xiang)380伏電(dian)(dian)源。