變壓器是用來變換交流電壓、電流而傳輸交流電能的一種靜止的電器設備。它是根據電磁感應的原理實現電能傳遞的。

        變(bian)(bian)(bian)(bian)壓(ya)(ya)(ya)(ya)(ya)(ya)器(qi)(qi)(qi)是(shi)(shi)用來(lai)變(bian)(bian)(bian)(bian)換交流電(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)(ya)(ya)、電(dian)(dian)(dian)(dian)流而傳(chuan)輸交流電(dian)(dian)(dian)(dian)能的(de)一種靜止的(de)電(dian)(dian)(dian)(dian)器(qi)(qi)(qi)設(she)備。它是(shi)(shi)根據電(dian)(dian)(dian)(dian)磁(ci)感應(ying)的(de)原理(li)實(shi)現電(dian)(dian)(dian)(dian)能傳(chuan)遞的(de)。變(bian)(bian)(bian)(bian)壓(ya)(ya)(ya)(ya)(ya)(ya)器(qi)(qi)(qi)就其(qi)用途可分為(wei)(wei)電(dian)(dian)(dian)(dian)力(li)(li)變(bian)(bian)(bian)(bian)壓(ya)(ya)(ya)(ya)(ya)(ya)器(qi)(qi)(qi)、試驗變(bian)(bian)(bian)(bian)壓(ya)(ya)(ya)(ya)(ya)(ya)器(qi)(qi)(qi)、儀用變(bian)(bian)(bian)(bian)壓(ya)(ya)(ya)(ya)(ya)(ya)器(qi)(qi)(qi)及特殊用途的(de)變(bian)(bian)(bian)(bian)壓(ya)(ya)(ya)(ya)(ya)(ya)器(qi)(qi)(qi)：電(dian)(dian)(dian)(dian)力(li)(li)變(bian)(bian)(bian)(bian)壓(ya)(ya)(ya)(ya)(ya)(ya)器(qi)(qi)(qi)是(shi)(shi)電(dian)(dian)(dian)(dian)力(li)(li)輸配(pei)電(dian)(dian)(dian)(dian)、電(dian)(dian)(dian)(dian)力(li)(li)用戶(hu)配(pei)電(dian)(dian)(dian)(dian)的(de)必(bi)要設(she)備；試驗變(bian)(bian)(bian)(bian)壓(ya)(ya)(ya)(ya)(ya)(ya)器(qi)(qi)(qi)對電(dian)(dian)(dian)(dian)器(qi)(qi)(qi)設(she)備進(jin)行耐壓(ya)(ya)(ya)(ya)(ya)(ya)（升壓(ya)(ya)(ya)(ya)(ya)(ya)）試驗的(de)設(she)備；儀用變(bian)(bian)(bian)(bian)壓(ya)(ya)(ya)(ya)(ya)(ya)器(qi)(qi)(qi)作為(wei)(wei)配(pei)電(dian)(dian)(dian)(dian)系統的(de)電(dian)(dian)(dian)(dian)氣測量、繼電(dian)(dian)(dian)(dian)保護之用（PT、CT）；特殊用途的(de)變(bian)(bian)(bian)(bian)壓(ya)(ya)(ya)(ya)(ya)(ya)器(qi)(qi)(qi)有冶煉用電(dian)(dian)(dian)(dian)爐變(bian)(bian)(bian)(bian)壓(ya)(ya)(ya)(ya)(ya)(ya)器(qi)(qi)(qi)、電(dian)(dian)(dian)(dian)焊變(bian)(bian)(bian)(bian)壓(ya)(ya)(ya)(ya)(ya)(ya)器(qi)(qi)(qi)、電(dian)(dian)(dian)(dian)解用整流變(bian)(bian)(bian)(bian)壓(ya)(ya)(ya)(ya)(ya)(ya)器(qi)(qi)(qi)、小(xiao)型調壓(ya)(ya)(ya)(ya)(ya)(ya)變(bian)(bian)(bian)(bian)壓(ya)(ya)(ya)(ya)(ya)(ya)器(qi)(qi)(qi)等。 

        電(dian)(dian)力(li)變(bian)壓(ya)(ya)(ya)器是(shi)(shi)一種(zhong)靜止的(de)(de)電(dian)(dian)氣設(she)(she)備，是(shi)(shi)用(yong)(yong)來(lai)將某一數(shu)(shu)值(zhi)的(de)(de)交(jiao)(jiao)流(liu)(liu)(liu)電(dian)(dian)壓(ya)(ya)(ya)（電(dian)(dian)流(liu)(liu)(liu)）變(bian)成(cheng)頻(pin)率相同(tong)的(de)(de)另一種(zhong)或幾種(zhong)數(shu)(shu)值(zhi)不(bu)同(tong)的(de)(de)電(dian)(dian)壓(ya)(ya)(ya)（電(dian)(dian)流(liu)(liu)(liu)）的(de)(de)設(she)(she)備。當一次繞組通以(yi)(yi)交(jiao)(jiao)流(liu)(liu)(liu)電(dian)(dian)時(shi)(shi)，就產生交(jiao)(jiao)變(bian)的(de)(de)磁(ci)(ci)(ci)通，交(jiao)(jiao)變(bian)的(de)(de)磁(ci)(ci)(ci)通通過鐵(tie)(tie)芯導磁(ci)(ci)(ci)作(zuo)用(yong)(yong)，就在二(er)次繞組中感(gan)應出交(jiao)(jiao)流(liu)(liu)(liu)電(dian)(dian)動(dong)勢(shi)。二(er)次感(gan)應電(dian)(dian)動(dong)勢(shi)的(de)(de)高(gao)低與一二(er)次繞組匝數(shu)(shu)的(de)(de)多少有關，即電(dian)(dian)壓(ya)(ya)(ya)大(da)小與匝數(shu)(shu)成(cheng)正比。主(zhu)要作(zuo)用(yong)(yong)是(shi)(shi)傳(chuan)輸(shu)電(dian)(dian)能(neng)，因此，額定容量(liang)是(shi)(shi)它的(de)(de)主(zhu)要參數(shu)(shu)。額定容量(liang)是(shi)(shi)一個表現功(gong)率的(de)(de)慣用(yong)(yong)值(zhi)，它是(shi)(shi)表征傳(chuan)輸(shu)電(dian)(dian)能(neng)的(de)(de)大(da)小，以(yi)(yi)kVA或MVA表示，當對(dui)變(bian)壓(ya)(ya)(ya)器施加額定電(dian)(dian)壓(ya)(ya)(ya)時(shi)(shi)，根據(ju)它來(lai)確(que)定在規(gui)定條(tiao)件下(xia)不(bu)超過溫升限值(zhi)的(de)(de)額定電(dian)(dian)流(liu)(liu)(liu)。較為(wei)節能(neng)的(de)(de)電(dian)(dian)力(li)變(bian)壓(ya)(ya)(ya)器是(shi)(shi)非(fei)晶合金鐵(tie)(tie)心配電(dian)(dian)變(bian)壓(ya)(ya)(ya)器，其大(da)優點(dian)是(shi)(shi)，空載損耗值(zhi)特低。最終能(neng)否確(que)保空載損耗值(zhi)，是(shi)(shi)整個設(she)(she)計過程(cheng)中所(suo)要考(kao)慮(lv)(lv)的(de)(de)核心問題。當在產品結構布置時(shi)(shi)，除要考(kao)慮(lv)(lv)非(fei)晶合金鐵(tie)(tie)心本身(shen)不(bu)受外(wai)力(li)的(de)(de)作(zuo)用(yong)(yong)外(wai)，同(tong)時(shi)(shi)在計算時(shi)(shi)還須合理選取非(fei)晶合金的(de)(de)特性(xing)參數(shu)(shu)。