三相電加熱管

        380伏(fu)三(san)相四線(xian)(xian)電(dian)(dian)(dian)(dian)路中，任意兩根(gen)火線(xian)(xian)之(zhi)(zhi)間(jian)的(de)電(dian)(dian)(dian)(dian)壓都(dou)是(shi)380伏(fu)，任意一根(gen)火線(xian)(xian)與零(ling)線(xian)(xian)之(zhi)(zhi)間(jian)都(dou)可(ke)以(yi)組成220伏(fu)。這個系統可(ke)以(yi)形成三(san)種(zhong)(zhong)電(dian)(dian)(dian)(dian)源(yuan)：即單(dan)相220伏(fu)電(dian)(dian)(dian)(dian)源(yuan)，單(dan)相380伏(fu)電(dian)(dian)(dian)(dian)源(yuan)，三(san)相380伏(fu)電(dian)(dian)(dian)(dian)源(yuan)，第(di) I 種(zhong)(zhong)家用(yong)比較(jiao)多，第(di)三(san)種(zhong)(zhong)工廠里(li)電(dian)(dian)(dian)(dian)機類(lei)用(yong)得多，第(di)二種(zhong)(zhong)用(yong)得少，只有(you)交(jiao)流電(dian)(dian)(dian)(dian)焊機經常用(yong)到單(dan)相380伏(fu)電(dian)(dian)(dian)(dian)源(yuan)。