三相電加熱管

        380伏(fu)三(san)相四線電(dian)(dian)(dian)(dian)路中(zhong)，任(ren)意兩根(gen)火(huo)(huo)線之間(jian)的電(dian)(dian)(dian)(dian)壓(ya)都(dou)(dou)是380伏(fu)，任(ren)意一根(gen)火(huo)(huo)線與零線之間(jian)都(dou)(dou)可以組成220伏(fu)。這個(ge)系(xi)統可以形(xing)成三(san)種(zhong)電(dian)(dian)(dian)(dian)源(yuan)：即單相220伏(fu)電(dian)(dian)(dian)(dian)源(yuan)，單相380伏(fu)電(dian)(dian)(dian)(dian)源(yuan)，三(san)相380伏(fu)電(dian)(dian)(dian)(dian)源(yuan)，第 I 種(zhong)家用(yong)比較多，第三(san)種(zhong)工廠里電(dian)(dian)(dian)(dian)機(ji)類用(yong)得(de)多，第二種(zhong)用(yong)得(de)少，只有(you)交(jiao)流電(dian)(dian)(dian)(dian)焊機(ji)經常用(yong)到(dao)單相380伏(fu)電(dian)(dian)(dian)(dian)源(yuan)。