三相電加熱管

        380伏(fu)(fu)(fu)(fu)三(san)(san)相(xiang)四(si)線(xian)(xian)電(dian)路中(zhong)，任(ren)意(yi)兩根火線(xian)(xian)之間(jian)的電(dian)壓都(dou)是(shi)380伏(fu)(fu)(fu)(fu)，任(ren)意(yi)一根火線(xian)(xian)與零線(xian)(xian)之間(jian)都(dou)可(ke)以組(zu)成220伏(fu)(fu)(fu)(fu)。這個系(xi)統可(ke)以形(xing)成三(san)(san)種(zhong)(zhong)電(dian)源(yuan)：即單(dan)相(xiang)220伏(fu)(fu)(fu)(fu)電(dian)源(yuan)，單(dan)相(xiang)380伏(fu)(fu)(fu)(fu)電(dian)源(yuan)，三(san)(san)相(xiang)380伏(fu)(fu)(fu)(fu)電(dian)源(yuan)，第 I 種(zhong)(zhong)家用(yong)比較多(duo)，第三(san)(san)種(zhong)(zhong)工廠里電(dian)機(ji)類用(yong)得(de)多(duo)，第二種(zhong)(zhong)用(yong)得(de)少，只有交(jiao)流電(dian)焊(han)機(ji)經常用(yong)到單(dan)相(xiang)380伏(fu)(fu)(fu)(fu)電(dian)源(yuan)。