三相電加熱管

        380伏(fu)三相(xiang)四線電(dian)(dian)路中，任意(yi)兩根火線之間的電(dian)(dian)壓(ya)都(dou)是380伏(fu)，任意(yi)一(yi)根火線與零線之間都(dou)可(ke)(ke)以組成220伏(fu)。這(zhe)個系統可(ke)(ke)以形成三種電(dian)(dian)源(yuan)(yuan)(yuan)：即單相(xiang)220伏(fu)電(dian)(dian)源(yuan)(yuan)(yuan)，單相(xiang)380伏(fu)電(dian)(dian)源(yuan)(yuan)(yuan)，三相(xiang)380伏(fu)電(dian)(dian)源(yuan)(yuan)(yuan)，第(di) I 種家用(yong)比較多，第(di)三種工廠(chang)里電(dian)(dian)機類用(yong)得多，第(di)二種用(yong)得少，只有交流電(dian)(dian)焊(han)機經常用(yong)到(dao)單相(xiang)380伏(fu)電(dian)(dian)源(yuan)(yuan)(yuan)。