三相電加熱管

        380伏三相(xiang)(xiang)四線電(dian)(dian)(dian)(dian)路(lu)中，任意兩根火線之間的(de)電(dian)(dian)(dian)(dian)壓都是380伏，任意一(yi)根火線與零線之間都可以(yi)組成220伏。這個系統(tong)可以(yi)形成三種(zhong)電(dian)(dian)(dian)(dian)源(yuan)：即單相(xiang)(xiang)220伏電(dian)(dian)(dian)(dian)源(yuan)，單相(xiang)(xiang)380伏電(dian)(dian)(dian)(dian)源(yuan)，三相(xiang)(xiang)380伏電(dian)(dian)(dian)(dian)源(yuan)，第 I 種(zhong)家用比較多，第三種(zhong)工廠里電(dian)(dian)(dian)(dian)機類用得多，第二種(zhong)用得少，只有交(jiao)流電(dian)(dian)(dian)(dian)焊機經常(chang)用到單相(xiang)(xiang)380伏電(dian)(dian)(dian)(dian)源(yuan)。