三相(xiang)除塵電(dian)(dian)(dian)源(yuan)由(you)三個頻率相(xiang)同，振幅(fu)相(xiang)等，相(xiang)位(wei)依次互差(cha)120度(du)電(dian)(dian)(dian)角(jiao)度(du)的(de)交(jiao)流(liu)(liu)(liu)(liu)電(dian)(dian)(dian)勢組成的(de)電(dian)(dian)(dian)源(yuan)稱為三相(xiang)交(jiao)流(liu)(liu)(liu)(liu)電(dian)(dian)(dian)源(yuan)。它是由(you)三相(xiang)交(jiao)流(liu)(liu)(liu)(liu)發(fa)電(dian)(dian)(dian)機產生(sheng)的(de)。日(ri)常生(sheng)活中所用(yong)的(de)單相(xiang)交(jiao)流(liu)(liu)(liu)(liu)電(dian)(dian)(dian)，實際上是由(you)三相(xiang)交(jiao)流(liu)(liu)(liu)(liu)電(dian)(dian)(dian)的(de)一相(xiang)提供的(de)，由(you)單相(xiang)發(fa)電(dian)(dian)(dian)機發(fa)出的(de)單相(xiang)交(jiao)流(liu)(liu)(liu)(liu)電(dian)(dian)(dian)源(yuan)已經很少采用(yong)。

優點

三相(xiang)(xiang)(xiang)(xiang)(xiang)(xiang)交(jiao)流電(dian)較單相(xiang)(xiang)(xiang)(xiang)(xiang)(xiang)交(jiao)流電(dian)有(you)(you)很多(duo)優(you)點，它在(zai)(zai)發(fa)電(dian)、輸(shu)(shu)(shu)配(pei)電(dian)以及電(dian)能(neng)轉換成機(ji)械能(neng)等方面都有(you)(you)明顯的優(you)越性(xing)。例如：制造(zao)三相(xiang)(xiang)(xiang)(xiang)(xiang)(xiang)發(fa)電(dian)機(ji)、變(bian)壓(ya)器(qi)都較制造(zao)容(rong)量相(xiang)(xiang)(xiang)(xiang)(xiang)(xiang)同(tong)的單相(xiang)(xiang)(xiang)(xiang)(xiang)(xiang)發(fa)電(dian)機(ji)、變(bian)壓(ya)器(qi)節(jie)省(sheng)材(cai)料，而且構造(zao)簡(jian)單，性(xing)能(neng)優(you)良，又如，由同(tong)樣(yang)材(cai)料所制造(zao)的三相(xiang)(xiang)(xiang)(xiang)(xiang)(xiang)電(dian)機(ji)，其容(rong)量比單相(xiang)(xiang)(xiang)(xiang)(xiang)(xiang)電(dian)機(ji)大50%，在(zai)(zai)輸(shu)(shu)(shu)送同(tong)樣(yang)功(gong)率的情況下，三相(xiang)(xiang)(xiang)(xiang)(xiang)(xiang)輸(shu)(shu)(shu)電(dian)線較單相(xiang)(xiang)(xiang)(xiang)(xiang)(xiang)輸(shu)(shu)(shu)電(dian)線可節(jie)省(sheng)有(you)(you)色金屬(shu)25%，而且電(dian)能(neng)損(sun)耗較單相(xiang)(xiang)(xiang)(xiang)(xiang)(xiang)輸(shu)(shu)(shu)電(dian)時少(shao)。由于三相(xiang)(xiang)(xiang)(xiang)(xiang)(xiang)交(jiao)流電(dian)有(you)(you)上述(shu)優(you)點所以獲得了廣泛的應用