三相電加熱管

        380伏(fu)三(san)相(xiang)四線(xian)(xian)電(dian)(dian)(dian)路(lu)中(zhong)，任(ren)意兩根火(huo)線(xian)(xian)之(zhi)間的(de)電(dian)(dian)(dian)壓都是380伏(fu)，任(ren)意一根火(huo)線(xian)(xian)與零線(xian)(xian)之(zhi)間都可(ke)以(yi)(yi)組成220伏(fu)。這個系(xi)統(tong)可(ke)以(yi)(yi)形成三(san)種(zhong)電(dian)(dian)(dian)源(yuan)：即單相(xiang)220伏(fu)電(dian)(dian)(dian)源(yuan)，單相(xiang)380伏(fu)電(dian)(dian)(dian)源(yuan)，三(san)相(xiang)380伏(fu)電(dian)(dian)(dian)源(yuan)，第(di)(di) I 種(zhong)家用比較多，第(di)(di)三(san)種(zhong)工(gong)廠里電(dian)(dian)(dian)機(ji)類用得(de)多，第(di)(di)二(er)種(zhong)用得(de)少，只(zhi)有(you)交流電(dian)(dian)(dian)焊機(ji)經(jing)常(chang)用到單相(xiang)380伏(fu)電(dian)(dian)(dian)源(yuan)。