電(dian)(dian)(dian)(dian)動機(ji)(ji)(ji)(ji)使(shi)(shi)(shi)用(yong)(yong)方(fang)便、運(yun)(yun)行(xing)可靠、價(jia)(jia)格(ge)低(di)(di)廉、結(jie)構牢固，但功率(lv)因(yin)數較(jiao)(jiao)低(di)(di)，調(diao)(diao)速也(ye)較(jiao)(jiao)困難。大(da)(da)容量低(di)(di)轉(zhuan)速的(de)動力機(ji)(ji)(ji)(ji)常(chang)用(yong)(yong)同(tong)(tong)步電(dian)(dian)(dian)(dian)動機(ji)(ji)(ji)(ji)（見同(tong)(tong)步電(dian)(dian)(dian)(dian)機(ji)(ji)(ji)(ji)）。同(tong)(tong)步電(dian)(dian)(dian)(dian)動機(ji)(ji)(ji)(ji)不(bu)但功率(lv)因(yin)數高，而且其轉(zhuan)速與(yu)負載大(da)(da)小無關，只決定(ding)于電(dian)(dian)(dian)(dian)網頻率(lv)。工作較(jiao)(jiao)穩定(ding)。在(zai)要求寬范圍調(diao)(diao)速的(de)場合多用(yong)(yong)直流(liu)電(dian)(dian)(dian)(dian)動機(ji)(ji)(ji)(ji)。但它有(you)換(huan)向器，結(jie)構復(fu)雜，價(jia)(jia)格(ge)昂貴，維(wei)護困難，不(bu)適于惡劣環境。20世紀70年代以后，隨(sui)(sui)著電(dian)(dian)(dian)(dian)力電(dian)(dian)(dian)(dian)子技術(shu)的(de)發(fa)展(zhan)，交流(liu)電(dian)(dian)(dian)(dian)動機(ji)(ji)(ji)(ji)的(de)調(diao)(diao)速技術(shu)漸趨成熟，設(she)備價(jia)(jia)格(ge)日(ri)益(yi)降(jiang)低(di)(di)，已開始(shi)得到(dao)應用(yong)(yong)。電(dian)(dian)(dian)(dian)動機(ji)(ji)(ji)(ji)在(zai)規定(ding)工作制式（連續(xu)式、短(duan)時運(yun)(yun)行(xing)制、斷續(xu)周期(qi)運(yun)(yun)行(xing)制）下所能承擔而不(bu)至(zhi)引起電(dian)(dian)(dian)(dian)機(ji)(ji)(ji)(ji)過熱(re)的(de)輸出(chu)機(ji)(ji)(ji)(ji)械功率(lv)稱為它的(de)額定(ding)功率(lv)，使(shi)(shi)(shi)用(yong)(yong)時需注意銘牌(pai)上的(de)規定(ding)。電(dian)(dian)(dian)(dian)動機(ji)(ji)(ji)(ji)運(yun)(yun)行(xing)時需注意使(shi)(shi)(shi)其負載的(de)特(te)性與(yu)電(dian)(dian)(dian)(dian)機(ji)(ji)(ji)(ji)的(de)特(te)性相(xiang)匹配，避免(mian)出(chu)現飛車或(huo)停轉(zhuan)。電(dian)(dian)(dian)(dian)動機(ji)(ji)(ji)(ji)能提供(gong)的(de)功率(lv)范圍很(hen)大(da)(da)，從毫瓦級(ji)到(dao)萬千瓦級(ji)。電(dian)(dian)(dian)(dian)動機(ji)(ji)(ji)(ji)的(de)使(shi)(shi)(shi)用(yong)(yong)和控制非(fei)常(chang)方(fang)便，具(ju)有(you)自(zi)起動、加速、制動、反轉(zhuan)、掣(che)住等能力。一般(ban)電(dian)(dian)(dian)(dian)動機(ji)(ji)(ji)(ji)調(diao)(diao)速時其輸出(chu)功率(lv)會隨(sui)(sui)轉(zhuan)速而變化。