三相電加熱管

        380伏(fu)三(san)相(xiang)四線(xian)(xian)電(dian)(dian)路中(zhong)，任意兩根火線(xian)(xian)之間的電(dian)(dian)壓都是380伏(fu)，任意一(yi)根火線(xian)(xian)與(yu)零線(xian)(xian)之間都可(ke)以組成220伏(fu)。這(zhe)個系統可(ke)以形成三(san)種電(dian)(dian)源(yuan)：即單(dan)(dan)相(xiang)220伏(fu)電(dian)(dian)源(yuan)，單(dan)(dan)相(xiang)380伏(fu)電(dian)(dian)源(yuan)，三(san)相(xiang)380伏(fu)電(dian)(dian)源(yuan)，第(di) I 種家用(yong)比較多，第(di)三(san)種工廠里電(dian)(dian)機(ji)類用(yong)得(de)多，第(di)二(er)種用(yong)得(de)少，只有交流電(dian)(dian)焊(han)機(ji)經(jing)常用(yong)到單(dan)(dan)相(xiang)380伏(fu)電(dian)(dian)源(yuan)。