三相電加熱管

        380伏三相(xiang)四線(xian)電(dian)(dian)路(lu)中，任意兩根火(huo)(huo)線(xian)之間的電(dian)(dian)壓都是380伏，任意一根火(huo)(huo)線(xian)與零線(xian)之間都可(ke)以組成220伏。這個系(xi)統可(ke)以形成三種(zhong)(zhong)電(dian)(dian)源(yuan)(yuan)：即單(dan)相(xiang)220伏電(dian)(dian)源(yuan)(yuan)，單(dan)相(xiang)380伏電(dian)(dian)源(yuan)(yuan)，三相(xiang)380伏電(dian)(dian)源(yuan)(yuan)，第 I 種(zhong)(zhong)家用比較多(duo)，第三種(zhong)(zhong)工廠里電(dian)(dian)機(ji)類用得(de)(de)多(duo)，第二種(zhong)(zhong)用得(de)(de)少，只(zhi)有交流電(dian)(dian)焊機(ji)經常用到單(dan)相(xiang)380伏電(dian)(dian)源(yuan)(yuan)。