當市(shi)電(dian)(dian)(dian)供電(dian)(dian)(dian)中斷或市(shi)電(dian)(dian)(dian)電(dian)(dian)(dian)壓超(chao)限 (±15%或±20%額定(ding)輸入(ru)電(dian)(dian)(dian)壓)時(shi)(shi),互投(tou)(tou)裝(zhuang)置將立即投(tou)(tou)切至逆(ni)(ni)變(bian)器(qi)供電(dian)(dian)(dian),在電(dian)(dian)(dian)池組所(suo)提(ti)供的(de)直(zhi)流能源(yuan)的(de)支(zhi)持(chi)下,此(ci)時(shi)(shi),用(yong)戶負(fu)載所(suo)使用(yong)的(de)電(dian)(dian)(dian)源(yuan)是通(tong)過(guo)EPS的(de)逆(ni)(ni)變(bian)器(qi)轉(zhuan)換的(de)交流電(dian)(dian)(dian)源(yuan),而不是來自(zi)市(shi)電(dian)(dian)(dian)