三相電加熱管

        380伏三相(xiang)四線(xian)電(dian)(dian)路(lu)中，任意(yi)兩根(gen)火線(xian)之間(jian)的(de)電(dian)(dian)壓都是380伏，任意(yi)一根(gen)火線(xian)與零(ling)線(xian)之間(jian)都可(ke)以組成(cheng)220伏。這個(ge)系統(tong)可(ke)以形(xing)成(cheng)三種電(dian)(dian)源(yuan)(yuan)：即(ji)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 種家用(yong)比較多(duo)，第三種工廠里電(dian)(dian)機類用(yong)得(de)多(duo)，第二種用(yong)得(de)少，只(zhi)有交流電(dian)(dian)焊機經常用(yong)到單(dan)相(xiang)380伏電(dian)(dian)源(yuan)(yuan)。