三相電加熱管

        380伏(fu)三相(xiang)四線(xian)電(dian)(dian)路中(zhong)，任意兩根(gen)火(huo)線(xian)之間(jian)的電(dian)(dian)壓都(dou)是380伏(fu)，任意一根(gen)火(huo)線(xian)與零(ling)線(xian)之間(jian)都(dou)可以組成(cheng)220伏(fu)。這(zhe)個系統可以形成(cheng)三種電(dian)(dian)源(yuan)：即單(dan)相(xiang)220伏(fu)電(dian)(dian)源(yuan)，單(dan)相(xiang)380伏(fu)電(dian)(dian)源(yuan)，三相(xiang)380伏(fu)電(dian)(dian)源(yuan)，第 I 種家用(yong)比較多，第三種工廠(chang)里電(dian)(dian)機類用(yong)得(de)多，第二種用(yong)得(de)少，只(zhi)有交流電(dian)(dian)焊機經常用(yong)到單(dan)相(xiang)380伏(fu)電(dian)(dian)源(yuan)。