三相電加熱管

        380伏(fu)三(san)相四線電(dian)(dian)(dian)路(lu)中，任意兩(liang)根火(huo)線之間的電(dian)(dian)(dian)壓都是380伏(fu)，任意一根火(huo)線與零線之間都可以組成220伏(fu)。這個系統(tong)可以形成三(san)種電(dian)(dian)(dian)源(yuan)：即單相220伏(fu)電(dian)(dian)(dian)源(yuan)，單相380伏(fu)電(dian)(dian)(dian)源(yuan)，三(san)相380伏(fu)電(dian)(dian)(dian)源(yuan)，第 I 種家用比較多(duo)，第三(san)種工(gong)廠里電(dian)(dian)(dian)機(ji)類用得(de)多(duo)，第二種用得(de)少，只(zhi)有(you)交流(liu)電(dian)(dian)(dian)焊機(ji)經常用到單相380伏(fu)電(dian)(dian)(dian)源(yuan)。