三相電加熱管

        380伏三相(xiang)(xiang)四線(xian)電(dian)(dian)路中(zhong)，任(ren)意兩(liang)根火線(xian)之間的電(dian)(dian)壓(ya)都是380伏，任(ren)意一根火線(xian)與(yu)零線(xian)之間都可以組成220伏。這個系統可以形成三種(zhong)電(dian)(dian)源(yuan)(yuan)：即單(dan)相(xiang)(xiang)220伏電(dian)(dian)源(yuan)(yuan)，單(dan)相(xiang)(xiang)380伏電(dian)(dian)源(yuan)(yuan)，三相(xiang)(xiang)380伏電(dian)(dian)源(yuan)(yuan)，第 I 種(zhong)家用比(bi)較多，第三種(zhong)工廠(chang)里電(dian)(dian)機類用得(de)多，第二種(zhong)用得(de)少，只有交流電(dian)(dian)焊機經常用到單(dan)相(xiang)(xiang)380伏電(dian)(dian)源(yuan)(yuan)。