三相電加熱管

        380伏(fu)(fu)(fu)(fu)三相(xiang)四(si)線電(dian)(dian)(dian)(dian)(dian)路中(zhong)，任意(yi)兩根火線之間(jian)(jian)的電(dian)(dian)(dian)(dian)(dian)壓都(dou)是380伏(fu)(fu)(fu)(fu)，任意(yi)一根火線與零(ling)線之間(jian)(jian)都(dou)可以組成(cheng)220伏(fu)(fu)(fu)(fu)。這個系統可以形成(cheng)三種(zhong)電(dian)(dian)(dian)(dian)(dian)源(yuan)：即單相(xiang)220伏(fu)(fu)(fu)(fu)電(dian)(dian)(dian)(dian)(dian)源(yuan)，單相(xiang)380伏(fu)(fu)(fu)(fu)電(dian)(dian)(dian)(dian)(dian)源(yuan)，三相(xiang)380伏(fu)(fu)(fu)(fu)電(dian)(dian)(dian)(dian)(dian)源(yuan)，第 I 種(zhong)家用比較多，第三種(zhong)工廠(chang)里電(dian)(dian)(dian)(dian)(dian)機(ji)類用得多，第二種(zhong)用得少，只(zhi)有交(jiao)流電(dian)(dian)(dian)(dian)(dian)焊機(ji)經常(chang)用到單相(xiang)380伏(fu)(fu)(fu)(fu)電(dian)(dian)(dian)(dian)(dian)源(yuan)。