電(dian)(dian)(dian)動(dong)機(ji)(ji)過負荷(he)保護是最常(chang)見和(he)應用的(de)一種(zhong)(zhong)保護,其(qi)(qi)保護功能和(he)常(chang)規熱(re)繼電(dian)(dian)(dian)器(qi)極為相似(si)。眾所周知(zhi),電(dian)(dian)(dian)動(dong)機(ji)(ji)是一種(zhong)(zhong)連續運(yun)行(xing)的(de)設(she)備,一般在(zai)其(qi)(qi)額定(ding)(ding)電(dian)(dian)(dian)流(liu)以下(xia)運(yun)行(xing),也允許在(zai)一段(duan)時間(jian)內(nei)在(zai)其(qi)(qi)額定(ding)(ding)電(dian)(dian)(dian)流(liu)以上(shang)運(yun)行(xing),但長時間(jian)超過其(qi)(qi)額定(ding)(ding)電(dian)(dian)(dian)流(liu)運(yun)行(xing),將造成電(dian)(dian)(dian)機(ji)(ji)過熱(re),絕(jue)緣降低而燒毀電(dian)(dian)(dian)機(ji)(ji)。
SJD550電動機保護控制器會在電(dian)機的熱積累達到一定值時,輸出繼電(dian)器跳閘,跳閘后(hou),熱容如果沒有(you)下降(jiang)到15%以下,電(dian)機是不(bu)允許被起動,緊急情況下可以同時按(an)停車復(fu)位按(an)鍵,進行(xing)人為清除熱記(ji)憶值。