【熱繼(ji)電(dian)器(qi)】熱繼(ji)電(dian)器(qi)工作原理 熱繼(ji)電(dian)器(qi)型號 熱繼(ji)電(dian)器(qi)的作用

一、熱繼電器工作原理

熱繼電器是用于電動機或其它電氣設備、電氣線(xian)路的過載(zai)保護(hu)的保護(hu)電器。

電(dian)(dian)(dian)動(dong)機(ji)(ji)(ji)(ji)(ji)(ji)在實際運行(xing)中，如拖動(dong)生產機(ji)(ji)(ji)(ji)(ji)(ji)械(xie)進行(xing)工作過(guo)(guo)程中，若機(ji)(ji)(ji)(ji)(ji)(ji)械(xie)出現不正常的(de)情況或(huo)電(dian)(dian)(dian)路異常使電(dian)(dian)(dian)動(dong)機(ji)(ji)(ji)(ji)(ji)(ji)遇到過(guo)(guo)載(zai)，則電(dian)(dian)(dian)動(dong)機(ji)(ji)(ji)(ji)(ji)(ji)轉(zhuan)速下降、繞(rao)(rao)組(zu)(zu)(zu)中的(de)電(dian)(dian)(dian)流(liu)(liu)將增大(da)，使電(dian)(dian)(dian)動(dong)機(ji)(ji)(ji)(ji)(ji)(ji)的(de)繞(rao)(rao)組(zu)(zu)(zu)溫度升(sheng)(sheng)高(gao)。若過(guo)(guo)載(zai)電(dian)(dian)(dian)流(liu)(liu)不大(da)且過(guo)(guo)載(zai)的(de)時(shi)間較(jiao)短，電(dian)(dian)(dian)動(dong)機(ji)(ji)(ji)(ji)(ji)(ji)繞(rao)(rao)組(zu)(zu)(zu)不超過(guo)(guo)允(yun)許(xu)溫升(sheng)(sheng)，這種(zhong)過(guo)(guo)載(zai)是允(yun)許(xu)的(de)。但若過(guo)(guo)載(zai)時(shi)間長，過(guo)(guo)載(zai)電(dian)(dian)(dian)流(liu)(liu)大(da)，電(dian)(dian)(dian)動(dong)機(ji)(ji)(ji)(ji)(ji)(ji)繞(rao)(rao)組(zu)(zu)(zu)的(de)溫升(sheng)(sheng)就會超過(guo)(guo)允(yun)許(xu)值，使電(dian)(dian)(dian)動(dong)機(ji)(ji)(ji)(ji)(ji)(ji)繞(rao)(rao)組(zu)(zu)(zu)老化(hua)，縮短電(dian)(dian)(dian)動(dong)機(ji)(ji)(ji)(ji)(ji)(ji)的(de)使用壽命，嚴重時(shi)甚至會使電(dian)(dian)(dian)動(dong)機(ji)(ji)(ji)(ji)(ji)(ji)繞(rao)(rao)組(zu)(zu)(zu)燒毀。所(suo)以，這種(zhong)過(guo)(guo)載(zai)是電(dian)(dian)(dian)動(dong)機(ji)(ji)(ji)(ji)(ji)(ji)不能承受的(de)。熱繼電(dian)(dian)(dian)器就是利用電(dian)(dian)(dian)流(liu)(liu)的(de)熱效應(ying)原理，在出現電(dian)(dian)(dian)動(dong)機(ji)(ji)(ji)(ji)(ji)(ji)不能承受的(de)過(guo)(guo)載(zai)時(shi)切(qie)斷電(dian)(dian)(dian)動(dong)機(ji)(ji)(ji)(ji)(ji)(ji)電(dian)(dian)(dian)路，為電(dian)(dian)(dian)動(dong)機(ji)(ji)(ji)(ji)(ji)(ji)提(ti)供過(guo)(guo)載(zai)保護(hu)的(de)保護(hu)電(dian)(dian)(dian)器。

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使用(yong)熱(re)繼電器(qi)對電動(dong)(dong)(dong)機進(jin)行過載保護時(shi)，將熱(re)元件與(yu)(yu)電動(dong)(dong)(dong)機的(de)定(ding)子繞(rao)組串聯，將熱(re)繼電器(qi)的(de)常(chang)(chang)閉(bi)觸(chu)頭串聯在(zai)交流(liu)接(jie)觸(chu)器(qi)的(de)電磁線(xian)圈的(de)控制(zhi)電路中，并(bing)調節整定(ding)電流(liu)調節旋鈕(niu)，使人字(zi)形撥桿(gan)(gan)與(yu)(yu)推桿(gan)(gan)相(xiang)距一適當距離。當電動(dong)(dong)(dong)機正常(chang)(chang)工作時(shi)，通過熱(re)元件的(de)電流(liu)即(ji)為(wei)電動(dong)(dong)(dong)機的(de)額定(ding)電流(liu)，熱(re)元件發熱(re)，雙金屬片受熱(re)后彎曲(qu)，使推桿(gan)(gan)剛(gang)好與(yu)(yu)人字(zi)形撥桿(gan)(gan)接(jie)觸(chu)，而又(you)不能推動(dong)(dong)(dong)人字(zi)形撥桿(gan)(gan)。常(chang)(chang)閉(bi)觸(chu)頭處(chu)于閉(bi)合狀態，交流(liu)接(jie)觸(chu)器(qi)保持吸合，電動(dong)(dong)(dong)機正常(chang)(chang)運行。

若電(dian)(dian)動(dong)機出現過載情況(kuang)，繞組中(zhong)電(dian)(dian)流(liu)增(zeng)大，通過熱繼電(dian)(dian)器元(yuan)件(jian)中(zhong)的(de)(de)電(dian)(dian)流(liu)增(zeng)大使雙(shuang)金屬片(pian)溫度升得更高，彎曲程度加大，推(tui)動(dong)人字形(xing)撥桿(gan)，人字形(xing)撥桿(gan)推(tui)動(dong)常閉(bi)觸頭，使觸頭斷(duan)開而斷(duan)開交流(liu)接觸器線圈電(dian)(dian)路，使接觸器釋放、切(qie)斷(duan)電(dian)(dian)動(dong)機的(de)(de)電(dian)(dian)源(yuan)，電(dian)(dian)動(dong)機停車而得到保護。

螺(luo)釘8是常(chang)(chang)閉(bi)觸(chu)頭(tou)復(fu)(fu)位(wei)(wei)方(fang)(fang)式調節螺(luo)釘。當螺(luo)釘位(wei)(wei)置靠左時(shi)，電(dian)(dian)(dian)(dian)動(dong)(dong)機(ji)(ji)(ji)過載后(hou)，常(chang)(chang)閉(bi)觸(chu)頭(tou)斷開，電(dian)(dian)(dian)(dian)動(dong)(dong)機(ji)(ji)(ji)停車后(hou)，熱繼(ji)(ji)(ji)電(dian)(dian)(dian)(dian)器(qi)雙金屬片冷卻復(fu)(fu)位(wei)(wei)。常(chang)(chang)閉(bi)觸(chu)頭(tou)的動(dong)(dong)觸(chu)頭(tou)在彈簧的作(zuo)用下(xia)會自(zi)(zi)動(dong)(dong)復(fu)(fu)位(wei)(wei)。此時(shi)熱繼(ji)(ji)(ji)電(dian)(dian)(dian)(dian)器(qi)為(wei)自(zi)(zi)動(dong)(dong)復(fu)(fu)位(wei)(wei)狀態(tai)。將(jiang)螺(luo)釘逆時(shi)針(zhen)旋(xuan)轉向右(you)調到(dao)一定位(wei)(wei)置時(shi)，若這(zhe)時(shi)電(dian)(dian)(dian)(dian)動(dong)(dong)機(ji)(ji)(ji)過載，熱繼(ji)(ji)(ji)電(dian)(dian)(dian)(dian)器(qi)的常(chang)(chang)閉(bi)觸(chu)頭(tou)斷開。其動(dong)(dong)觸(chu)頭(tou)將(jiang)擺到(dao)右(you)側一新的平(ping)衡位(wei)(wei)置。電(dian)(dian)(dian)(dian)動(dong)(dong)機(ji)(ji)(ji)斷電(dian)(dian)(dian)(dian)停車后(hou)，動(dong)(dong)觸(chu)頭(tou)不能(neng)復(fu)(fu)位(wei)(wei)。必須(xu)按動(dong)(dong)復(fu)(fu)位(wei)(wei)按鈕后(hou)動(dong)(dong)觸(chu)頭(tou)方(fang)(fang)能(neng)復(fu)(fu)位(wei)(wei)。此時(shi)熱繼(ji)(ji)(ji)電(dian)(dian)(dian)(dian)器(qi)為(wei)手動(dong)(dong)復(fu)(fu)位(wei)(wei)狀態(tai)。若電(dian)(dian)(dian)(dian)動(dong)(dong)機(ji)(ji)(ji)過載是故障性(xing)的，為(wei)了(le)避免再次輕易(yi)地起(qi)動(dong)(dong)電(dian)(dian)(dian)(dian)動(dong)(dong)機(ji)(ji)(ji)，熱繼(ji)(ji)(ji)電(dian)(dian)(dian)(dian)器(qi)宜采用手動(dong)(dong)復(fu)(fu)位(wei)(wei)方(fang)(fang)式。若要將(jiang)熱繼(ji)(ji)(ji)電(dian)(dian)(dian)(dian)器(qi)由手動(dong)(dong)復(fu)(fu)位(wei)(wei)方(fang)(fang)式調至自(zi)(zi)動(dong)(dong)復(fu)(fu)位(wei)(wei)方(fang)(fang)式，只需將(jiang)復(fu)(fu)位(wei)(wei)調節螺(luo)釘順時(shi)針(zhen)旋(xuan)進至適當位(wei)(wei)置即可。

二、熱繼電器型號

NR2熱繼電器NR2-11.5/Z 0.1-13A、NR2熱繼電器(qi)NR2-25G/Z 0.1-10A、NR2熱(re)繼電器(qi)NR2-25G/Z 13-25A、NR2熱繼(ji)電器NR2-36G/Z 23-36A、NR2熱繼電器NR2-93G/Z 23-80A等。

熱(re)繼電器選型方法：

1，熱繼電器的(de)選(xuan)擇應等于或(huo)大(da)于電機的(de)額定(ding)電流。

2，熱繼電(dian)(dian)器(qi)的(de)額(e)定電(dian)(dian)流為電(dian)(dian)動機額(e)定電(dian)(dian)流的(de)（0.95-1.05）倍。

3，對于電機電路，熱(re)繼電器的整定(ding)(ding)電流(liu)應等于電機的額定(ding)(ding)電流(liu)。

4，當熱繼電(dian)器周圍的環境溫度(du)不(bu)是35℃時，應該設定為：（95-T）/ 60平方t：環境溫(wen)度。

三、熱繼電器的作用

主(zhu)要用來對(dui)異(yi)步電動(dong)機進(jin)行過(guo)(guo)(guo)載保護，他的(de)工作(zuo)(zuo)原理是(shi)過(guo)(guo)(guo)載電流(liu)通過(guo)(guo)(guo)熱元件(jian)后，使(shi)雙(shuang)金屬片加熱彎(wan)曲(qu)去推動(dong)動(dong)作(zuo)(zuo)機構來帶動(dong)觸(chu)點動(dong)作(zuo)(zuo)，從而(er)將電動(dong)機控制電路(lu)斷開實現電動(dong)機斷電停(ting)車，起到過(guo)(guo)(guo)載保護的(de)作(zuo)(zuo)用。鑒于雙(shuang)金屬片受熱彎(wan)曲(qu)過(guo)(guo)(guo)程中，熱量的(de)傳遞需要較長的(de)時間，因此，熱繼電器不能(neng)(neng)用作(zuo)(zuo)短路(lu)保護，而(er)只(zhi)能(neng)(neng)用作(zuo)(zuo)過(guo)(guo)(guo)載保護熱繼電器的(de)過(guo)(guo)(guo)載保護。

熱繼電器其它(ta)部分的(de)(de)(de)作(zuo)用(yong)如下：人(ren)字(zi)(zi)形(xing)撥(bo)桿(gan)(gan)的(de)(de)(de)左(zuo)臂(bei)也用(yong)雙(shuang)金屬片(pian)制成，當環境溫度發生變化時，主電(dian)路中的(de)(de)(de)雙(shuang)金屬片(pian)會(hui)產生一定的(de)(de)(de)變形(xing)彎曲(qu)，這(zhe)時人(ren)字(zi)(zi)形(xing)撥(bo)桿(gan)(gan)的(de)(de)(de)左(zuo)臂(bei)也會(hui)發生同方向的(de)(de)(de)變形(xing)彎曲(qu)，從而使人(ren)字(zi)(zi)形(xing)撥(bo)桿(gan)(gan)與推桿(gan)(gan)之(zhi)間的(de)(de)(de)距(ju)離基本(ben)保(bao)持不變，保(bao)證熱繼電(dian)器動作(zuo)的(de)(de)(de)準確性(xing)。這(zhe)種作(zuo)用(yong)稱溫度補償作(zuo)用(yong)。