三相電加熱管

        380伏(fu)(fu)(fu)(fu)三相(xiang)(xiang)四線(xian)電(dian)(dian)(dian)(dian)路(lu)中，任(ren)意(yi)兩(liang)根火線(xian)之(zhi)間的電(dian)(dian)(dian)(dian)壓都是380伏(fu)(fu)(fu)(fu)，任(ren)意(yi)一根火線(xian)與(yu)零(ling)線(xian)之(zhi)間都可以組成(cheng)(cheng)220伏(fu)(fu)(fu)(fu)。這個系統可以形(xing)成(cheng)(cheng)三種(zhong)電(dian)(dian)(dian)(dian)源(yuan)(yuan)(yuan)：即(ji)單(dan)相(xiang)(xiang)220伏(fu)(fu)(fu)(fu)電(dian)(dian)(dian)(dian)源(yuan)(yuan)(yuan)，單(dan)相(xiang)(xiang)380伏(fu)(fu)(fu)(fu)電(dian)(dian)(dian)(dian)源(yuan)(yuan)(yuan)，三相(xiang)(xiang)380伏(fu)(fu)(fu)(fu)電(dian)(dian)(dian)(dian)源(yuan)(yuan)(yuan)，第(di) I 種(zhong)家用(yong)比(bi)較多(duo)，第(di)三種(zhong)工廠(chang)里電(dian)(dian)(dian)(dian)機類(lei)用(yong)得(de)多(duo)，第(di)二種(zhong)用(yong)得(de)少，只(zhi)有交流電(dian)(dian)(dian)(dian)焊機經常(chang)用(yong)到單(dan)相(xiang)(xiang)380伏(fu)(fu)(fu)(fu)電(dian)(dian)(dian)(dian)源(yuan)(yuan)(yuan)。