每個電氣設備都有它的(de)額(e)定功(gong)率，當超過額(e)定功(gong)率是就叫(jiao)做(zuo)過載(zai)，對這種狀態(tai)的(de)保護就叫(jiao)做(zuo)過載(zai)保護
對于防止(zhi)電(dian)氣(qi)設備內部發(fa)生(sheng)短路(lu)的保護就(jiu)叫做短路(lu)保護、
過(guo)電(dian)流是指(zhi)電(dian)動機或電(dian)器元件超(chao)過(guo)其額(e)定(ding)電(dian)流的運行狀態，過(guo)電(dian)流一般比(bi)短路(lu)電(dian)流小，在6倍額(e)定(ding)電(dian)流以(yi)內。
數字斷路器(qi)/空開(kai) 過流過載短路保護器(qi)EM-001AL
短路保護
電(dian)(dian)(dian)氣控(kong)制線路(lu)中的電(dian)(dian)(dian)器或(huo)配(pei)線絕(jue)緣遭(zao)到損壞(huai)、負載短(duan)路(lu)、接線錯誤(wu)時，都(dou)將產(chan)生(sheng)短(duan)路(lu)故(gu)障。短(duan)路(lu)時產(chan)生(sheng)的瞬時故(gu)障電(dian)(dian)(dian)流(liu)是額定電(dian)(dian)(dian)流(liu)的十(shi)幾(ji)至(zhi)幾(ji)十(shi)倍。電(dian)(dian)(dian)氣設備或(huo)配(pei)電(dian)(dian)(dian)線路(lu)因短(duan)路(lu)電(dian)(dian)(dian)流(liu)產(chan)生(sheng)的強大電(dian)(dian)(dian)動力可能損壞(huai)、產(chan)生(sheng)電(dian)(dian)(dian)弧，甚至(zhi)引起火災(zai)。
短路(lu)保護要求在短路(lu)故障(zhang)產(chan)生后的(de)極短時間內切斷(duan)電(dian)(dian)源，常(chang)用方法是在線路(lu)中串(chuan)接熔斷(duan)器(qi)或低(di)壓斷(duan)路(lu)器(qi)。低(di)壓斷(duan)路(lu)器(qi)動作電(dian)(dian)流整定為電(dian)(dian)動機起動電(dian)(dian)流的(de)1.2倍。
過電流保護
過(guo)(guo)電(dian)(dian)(dian)(dian)流(liu)(liu)(liu)是指(zhi)電(dian)(dian)(dian)(dian)動(dong)機(ji)或電(dian)(dian)(dian)(dian)器(qi)元(yuan)件(jian)超(chao)過(guo)(guo)其額(e)定電(dian)(dian)(dian)(dian)流(liu)(liu)(liu)的(de)(de)運行(xing)狀態，過(guo)(guo)電(dian)(dian)(dian)(dian)流(liu)(liu)(liu)一(yi)般比短(duan)路電(dian)(dian)(dian)(dian)流(liu)(liu)(liu)小，在6倍額(e)定電(dian)(dian)(dian)(dian)流(liu)(liu)(liu)以內。電(dian)(dian)(dian)(dian)氣線路中(zhong)發生過(guo)(guo)電(dian)(dian)(dian)(dian)流(liu)(liu)(liu)的(de)(de)可能性大(da)于(yu)短(duan)路，特別(bie)是在電(dian)(dian)(dian)(dian)動(dong)機(ji)頻繁(fan)起動(dong)和頻繁(fan)正反轉(zhuan)(zhuan)時。在過(guo)(guo)電(dian)(dian)(dian)(dian)流(liu)(liu)(liu)情況下，若能在達到最大(da)允許溫升之(zhi)前(qian)電(dian)(dian)(dian)(dian)流(liu)(liu)(liu)值恢復正常，電(dian)(dian)(dian)(dian)器(qi)元(yuan)件(jian)仍(reng)能正常工作，但是過(guo)(guo)電(dian)(dian)(dian)(dian)流(liu)(liu)(liu)造成的(de)(de)沖擊電(dian)(dian)(dian)(dian)流(liu)(liu)(liu)會損壞電(dian)(dian)(dian)(dian)動(dong)機(ji)，所產生的(de)(de)瞬(shun)時電(dian)(dian)(dian)(dian)磁大(da)轉(zhuan)(zhuan)矩會損壞機(ji)械(xie)傳動(dong)部(bu)件(jian)，因此要(yao)及時切(qie)斷電(dian)(dian)(dian)(dian)源(yuan)。
過(guo)電(dian)(dian)流(liu)(liu)保護常(chang)用過(guo)電(dian)(dian)流(liu)(liu)繼電(dian)(dian)器(qi)實(shi)現。將過(guo)電(dian)(dian)流(liu)(liu)繼電(dian)(dian)器(qi)線(xian)(xian)圈串接(jie)在(zai)(zai)被保護線(xian)(xian)路(lu)中(zhong)(zhong)，當(dang)電(dian)(dian)流(liu)(liu)達到其整定值，過(guo)電(dian)(dian)流(liu)(liu)繼電(dian)(dian)器(qi)動作，其常(chang)閉觸(chu)(chu)頭串接(jie)在(zai)(zai)接(jie)觸(chu)(chu)器(qi)線(xian)(xian)圈所在(zai)(zai)的支路(lu)中(zhong)(zhong)，使(shi)接(jie)觸(chu)(chu)器(qi)線(xian)(xian)圈斷(duan)(duan)(duan)電(dian)(dian)，再通(tong)過(guo)主電(dian)(dian)路(lu)中(zhong)(zhong)接(jie)觸(chu)(chu)器(qi)的主觸(chu)(chu)頭斷(duan)(duan)(duan)開，使(shi)電(dian)(dian)動機電(dian)(dian)源及時(shi)切斷(duan)(duan)(duan)。
綜合用電保護器EM-001AK
過載保護
過(guo)(guo)(guo)載是指(zhi)電(dian)動機運(yun)(yun)行電(dian)流(liu)超(chao)過(guo)(guo)(guo)其額定(ding)(ding)電(dian)流(liu)但小(xiao)于1.5倍額定(ding)(ding)電(dian)流(liu)的(de)運(yun)(yun)行狀(zhuang)態，此運(yun)(yun)行狀(zhuang)態在過(guo)(guo)(guo)電(dian)流(liu)運(yun)(yun)行狀(zhuang)態范圍內。若電(dian)動機長期過(guo)(guo)(guo)載運(yun)(yun)行，其繞組溫升將超(chao)過(guo)(guo)(guo)允許值而(er)絕緣老化或損壞。過(guo)(guo)(guo)載保(bao)護要求不受電(dian)動機短(duan)時過(guo)(guo)(guo)載沖(chong)擊電(dian)流(liu)或短(duan)路(lu)電(dian)流(liu)的(de)影響而(er)瞬(shun)時動作(zuo)(zuo)，通(tong)常采用(yong)熱繼電(dian)器(qi)作(zuo)(zuo)過(guo)(guo)(guo)載保(bao)護元件。
當6倍以上額定(ding)電流通過熱(re)(re)繼電器(qi)時(shi)，需經5s后才動(dong)作，可能在熱(re)(re)繼電器(qi)動(dong)作前(qian)，熱(re)(re)繼電器(qi)的加熱(re)(re)元件(jian)已燒壞(huai)，所(suo)以在使用(yong)熱(re)(re)繼電器(qi)作過載(zai)保護時(shi)，必(bi)須同時(shi)裝有(you)熔斷器(qi)或低壓斷路(lu)(lu)器(qi)等短路(lu)(lu)保護裝置。