相比異步電動機，高速永磁同步電動機在輕(qing)載(zai)(zai)時(shi)效(xiao)(xiao)率(lv)(lv)(lv)(lv)(lv)值(zhi)要(yao)高(gao)很(hen)多(duo)，其高(gao)效(xiao)(xiao)運(yun)(yun)行(xing)(xing)范圍寬，在25%～120%范圍內(nei)效(xiao)(xiao)率(lv)(lv)(lv)(lv)(lv)大于90%，高(gao)速(su)永磁(ci)同步電(dian)動(dong)(dong)(dong)機(ji)(ji)額定(ding)效(xiao)(xiao)率(lv)(lv)(lv)(lv)(lv)可達現(xian)行(xing)(xing)國(guo)標(biao)的(de)1級能效(xiao)(xiao)要(yao)求(qiu)(qiu)，這是其在節能方面(mian)，相(xiang)比異步電(dian)動(dong)(dong)(dong)機(ji)(ji)更大的(de)一(yi)(yi)(yi)(yi)個優(you)勢(shi)。實際運(yun)(yun)行(xing)(xing)中，電(dian)動(dong)(dong)(dong)機(ji)(ji)在驅(qu)動(dong)(dong)(dong)負(fu)載(zai)(zai)時(shi)很(hen)少以滿功率(lv)(lv)(lv)(lv)(lv)運(yun)(yun)行(xing)(xing)。其原(yuan)因是：一(yi)(yi)(yi)(yi)方面(mian)，設計人員在電(dian)動(dong)(dong)(dong)機(ji)(ji)選(xuan)型時(shi)，一(yi)(yi)(yi)(yi)般(ban)是依據負(fu)載(zai)(zai)的(de)極限工況來(lai)確(que)定(ding)電(dian)動(dong)(dong)(dong)機(ji)(ji)功率(lv)(lv)(lv)(lv)(lv)，而極限工況出現(xian)的(de)機(ji)(ji)會(hui)是很(hen)少的(de)，同時(shi)，為(wei)防止在異常(chang)(chang)工況時(shi)燒損電(dian)動(dong)(dong)(dong)機(ji)(ji)，設計時(shi)也會(hui)進一(yi)(yi)(yi)(yi)步給(gei)電(dian)動(dong)(dong)(dong)機(ji)(ji)的(de)功率(lv)(lv)(lv)(lv)(lv)留(liu)裕(yu)量；另(ling)一(yi)(yi)(yi)(yi)方面(mian)，電(dian)動(dong)(dong)(dong)機(ji)(ji)制造(zao)商為(wei)保證電(dian)動(dong)(dong)(dong)機(ji)(ji)的(de)可靠性，通常(chang)(chang)會(hui)在用(yong)戶要(yao)求(qiu)(qiu)的(de)功率(lv)(lv)(lv)(lv)(lv)基(ji)礎上(shang)，進一(yi)(yi)(yi)(yi)步留(liu)一(yi)(yi)(yi)(yi)定(ding)的(de)功率(lv)(lv)(lv)(lv)(lv)裕(yu)量。這樣(yang)就導致實際運(yun)(yun)行(xing)(xing)的(de)電(dian)動(dong)(dong)(dong)機(ji)(ji)，大多(duo)數工作(zuo)在額定(ding)功率(lv)(lv)(lv)(lv)(lv)的(de)70%以下，特別是驅(qu)動(dong)(dong)(dong)風機(ji)(ji)或泵(beng)類負(fu)載(zai)(zai)，電(dian)動(dong)(dong)(dong)機(ji)(ji)通常(chang)(chang)工作(zuo)在輕(qing)載(zai)(zai)區(qu)。對異步電(dian)動(dong)(dong)(dong)機(ji)(ji)來(lai)講，其輕(qing)載(zai)(zai)效(xiao)(xiao)率(lv)(lv)(lv)(lv)(lv)很(hen)低(di)，而高(gao)速(su)永磁(ci)同步電(dian)動(dong)(dong)(dong)機(ji)(ji)在輕(qing)載(zai)(zai)區(qu)，仍能保持較高(gao)的(de)效(xiao)(xiao)率(lv)(lv)(lv)(lv)(lv)。