三相電加熱管

        380伏三相四線電(dian)(dian)(dian)(dian)(dian)路中，任(ren)意兩根火(huo)線之(zhi)間的電(dian)(dian)(dian)(dian)(dian)壓(ya)都是380伏，任(ren)意一根火(huo)線與零線之(zhi)間都可以組成(cheng)220伏。這個系統(tong)可以形成(cheng)三種(zhong)電(dian)(dian)(dian)(dian)(dian)源：即單相220伏電(dian)(dian)(dian)(dian)(dian)源，單相380伏電(dian)(dian)(dian)(dian)(dian)源，三相380伏電(dian)(dian)(dian)(dian)(dian)源，第(di)(di) I 種(zhong)家用比(bi)較多，第(di)(di)三種(zhong)工廠里電(dian)(dian)(dian)(dian)(dian)機類用得(de)多，第(di)(di)二(er)種(zhong)用得(de)少(shao)，只有交流電(dian)(dian)(dian)(dian)(dian)焊機經常(chang)用到單相380伏電(dian)(dian)(dian)(dian)(dian)源。