三相電加熱管

        380伏(fu)三相(xiang)四線電(dian)(dian)路中，任意兩根火線之(zhi)間的電(dian)(dian)壓都是380伏(fu)，任意一根火線與零(ling)線之(zhi)間都可(ke)以組成220伏(fu)。這個系統可(ke)以形(xing)成三種(zhong)電(dian)(dian)源：即單(dan)相(xiang)220伏(fu)電(dian)(dian)源，單(dan)相(xiang)380伏(fu)電(dian)(dian)源，三相(xiang)380伏(fu)電(dian)(dian)源，第(di) I 種(zhong)家用(yong)比較多，第(di)三種(zhong)工廠里電(dian)(dian)機類用(yong)得多，第(di)二種(zhong)用(yong)得少，只有交流電(dian)(dian)焊機經常(chang)用(yong)到單(dan)相(xiang)380伏(fu)電(dian)(dian)源。