三相電加熱管

        380伏三相(xiang)四(si)線(xian)電(dian)(dian)(dian)路中，任(ren)(ren)意兩根火(huo)(huo)線(xian)之間的電(dian)(dian)(dian)壓(ya)都是(shi)380伏，任(ren)(ren)意一根火(huo)(huo)線(xian)與零線(xian)之間都可以組(zu)成220伏。這(zhe)個系統可以形成三種電(dian)(dian)(dian)源：即單(dan)相(xiang)220伏電(dian)(dian)(dian)源，單(dan)相(xiang)380伏電(dian)(dian)(dian)源，三相(xiang)380伏電(dian)(dian)(dian)源，第 I 種家(jia)用(yong)(yong)比較(jiao)多，第三種工廠里電(dian)(dian)(dian)機類用(yong)(yong)得多，第二種用(yong)(yong)得少，只有交流電(dian)(dian)(dian)焊(han)機經(jing)常(chang)用(yong)(yong)到單(dan)相(xiang)380伏電(dian)(dian)(dian)源。