三相電加熱管

        380伏(fu)三相(xiang)(xiang)四線電(dian)(dian)(dian)路(lu)中，任意(yi)兩根火(huo)線之間的電(dian)(dian)(dian)壓(ya)都(dou)是380伏(fu)，任意(yi)一根火(huo)線與零線之間都(dou)可(ke)以組成220伏(fu)。這個系統(tong)可(ke)以形成三種(zhong)(zhong)電(dian)(dian)(dian)源(yuan)(yuan)：即(ji)單相(xiang)(xiang)220伏(fu)電(dian)(dian)(dian)源(yuan)(yuan)，單相(xiang)(xiang)380伏(fu)電(dian)(dian)(dian)源(yuan)(yuan)，三相(xiang)(xiang)380伏(fu)電(dian)(dian)(dian)源(yuan)(yuan)，第(di) I 種(zhong)(zhong)家(jia)用(yong)比較多，第(di)三種(zhong)(zhong)工廠里電(dian)(dian)(dian)機(ji)類(lei)用(yong)得多，第(di)二(er)種(zhong)(zhong)用(yong)得少，只有交流(liu)電(dian)(dian)(dian)焊(han)機(ji)經常(chang)用(yong)到單相(xiang)(xiang)380伏(fu)電(dian)(dian)(dian)源(yuan)(yuan)。