三相電加熱管

        380伏三(san)相(xiang)四線(xian)電(dian)(dian)(dian)路中(zhong)，任意兩根(gen)火線(xian)之間的(de)電(dian)(dian)(dian)壓(ya)都(dou)是380伏，任意一(yi)根(gen)火線(xian)與零線(xian)之間都(dou)可以組成(cheng)220伏。這(zhe)個系統可以形成(cheng)三(san)種(zhong)(zhong)電(dian)(dian)(dian)源：即單(dan)相(xiang)220伏電(dian)(dian)(dian)源，單(dan)相(xiang)380伏電(dian)(dian)(dian)源，三(san)相(xiang)380伏電(dian)(dian)(dian)源，第(di) I 種(zhong)(zhong)家(jia)用(yong)(yong)比較(jiao)多，第(di)三(san)種(zhong)(zhong)工廠里電(dian)(dian)(dian)機類(lei)用(yong)(yong)得(de)多，第(di)二種(zhong)(zhong)用(yong)(yong)得(de)少，只有交流電(dian)(dian)(dian)焊機經常(chang)用(yong)(yong)到單(dan)相(xiang)380伏電(dian)(dian)(dian)源。