【熱繼(ji)(ji)(ji)電(dian)器】熱繼(ji)(ji)(ji)電(dian)器工(gong)作(zuo)原(yuan)理 熱繼(ji)(ji)(ji)電(dian)器型(xing)號 熱繼(ji)(ji)(ji)電(dian)器的(de)作(zuo)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(dian)氣線路的過載保護的保護電(dian)器(qi)。

電(dian)(dian)(dian)(dian)(dian)動(dong)機(ji)(ji)(ji)(ji)在實際運行中，如拖動(dong)生產(chan)機(ji)(ji)(ji)(ji)械進行工作過(guo)(guo)(guo)(guo)程中，若(ruo)機(ji)(ji)(ji)(ji)械出(chu)現不(bu)(bu)正常(chang)的(de)(de)情(qing)況或電(dian)(dian)(dian)(dian)(dian)路(lu)異常(chang)使(shi)電(dian)(dian)(dian)(dian)(dian)動(dong)機(ji)(ji)(ji)(ji)遇(yu)到過(guo)(guo)(guo)(guo)載(zai)(zai)，則電(dian)(dian)(dian)(dian)(dian)動(dong)機(ji)(ji)(ji)(ji)轉速下降、繞(rao)(rao)組中的(de)(de)電(dian)(dian)(dian)(dian)(dian)流(liu)(liu)將增(zeng)大(da)，使(shi)電(dian)(dian)(dian)(dian)(dian)動(dong)機(ji)(ji)(ji)(ji)的(de)(de)繞(rao)(rao)組溫(wen)度升高(gao)。若(ruo)過(guo)(guo)(guo)(guo)載(zai)(zai)電(dian)(dian)(dian)(dian)(dian)流(liu)(liu)不(bu)(bu)大(da)且過(guo)(guo)(guo)(guo)載(zai)(zai)的(de)(de)時(shi)間(jian)較短，電(dian)(dian)(dian)(dian)(dian)動(dong)機(ji)(ji)(ji)(ji)繞(rao)(rao)組不(bu)(bu)超過(guo)(guo)(guo)(guo)允許溫(wen)升，這(zhe)種(zhong)(zhong)過(guo)(guo)(guo)(guo)載(zai)(zai)是(shi)允許的(de)(de)。但若(ruo)過(guo)(guo)(guo)(guo)載(zai)(zai)時(shi)間(jian)長，過(guo)(guo)(guo)(guo)載(zai)(zai)電(dian)(dian)(dian)(dian)(dian)流(liu)(liu)大(da)，電(dian)(dian)(dian)(dian)(dian)動(dong)機(ji)(ji)(ji)(ji)繞(rao)(rao)組的(de)(de)溫(wen)升就會(hui)超過(guo)(guo)(guo)(guo)允許值，使(shi)電(dian)(dian)(dian)(dian)(dian)動(dong)機(ji)(ji)(ji)(ji)繞(rao)(rao)組老化(hua)，縮短電(dian)(dian)(dian)(dian)(dian)動(dong)機(ji)(ji)(ji)(ji)的(de)(de)使(shi)用壽命，嚴重(zhong)時(shi)甚至會(hui)使(shi)電(dian)(dian)(dian)(dian)(dian)動(dong)機(ji)(ji)(ji)(ji)繞(rao)(rao)組燒毀(hui)。所以，這(zhe)種(zhong)(zhong)過(guo)(guo)(guo)(guo)載(zai)(zai)是(shi)電(dian)(dian)(dian)(dian)(dian)動(dong)機(ji)(ji)(ji)(ji)不(bu)(bu)能(neng)承受(shou)的(de)(de)。熱繼電(dian)(dian)(dian)(dian)(dian)器就是(shi)利用電(dian)(dian)(dian)(dian)(dian)流(liu)(liu)的(de)(de)熱效(xiao)應原(yuan)理(li)，在出(chu)現電(dian)(dian)(dian)(dian)(dian)動(dong)機(ji)(ji)(ji)(ji)不(bu)(bu)能(neng)承受(shou)的(de)(de)過(guo)(guo)(guo)(guo)載(zai)(zai)時(shi)切斷電(dian)(dian)(dian)(dian)(dian)動(dong)機(ji)(ji)(ji)(ji)電(dian)(dian)(dian)(dian)(dian)路(lu)，為(wei)電(dian)(dian)(dian)(dian)(dian)動(dong)機(ji)(ji)(ji)(ji)提供過(guo)(guo)(guo)(guo)載(zai)(zai)保護的(de)(de)保護電(dian)(dian)(dian)(dian)(dian)器。

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使(shi)用(yong)熱(re)(re)(re)繼(ji)電(dian)(dian)器對(dui)電(dian)(dian)動(dong)(dong)(dong)機(ji)(ji)進行過載保(bao)護時(shi)，將熱(re)(re)(re)元(yuan)(yuan)件與(yu)電(dian)(dian)動(dong)(dong)(dong)機(ji)(ji)的(de)(de)定(ding)子繞組串聯，將熱(re)(re)(re)繼(ji)電(dian)(dian)器的(de)(de)常(chang)閉觸(chu)(chu)(chu)頭串聯在交(jiao)流(liu)接(jie)觸(chu)(chu)(chu)器的(de)(de)電(dian)(dian)磁線(xian)圈的(de)(de)控制電(dian)(dian)路中，并調節整定(ding)電(dian)(dian)流(liu)調節旋鈕，使(shi)人(ren)字形撥桿與(yu)推桿相距(ju)一適(shi)當距(ju)離(li)。當電(dian)(dian)動(dong)(dong)(dong)機(ji)(ji)正(zheng)常(chang)工作時(shi)，通(tong)過熱(re)(re)(re)元(yuan)(yuan)件的(de)(de)電(dian)(dian)流(liu)即為電(dian)(dian)動(dong)(dong)(dong)機(ji)(ji)的(de)(de)額定(ding)電(dian)(dian)流(liu)，熱(re)(re)(re)元(yuan)(yuan)件發熱(re)(re)(re)，雙金屬片受熱(re)(re)(re)后彎曲，使(shi)推桿剛(gang)好與(yu)人(ren)字形撥桿接(jie)觸(chu)(chu)(chu)，而又不能推動(dong)(dong)(dong)人(ren)字形撥桿。常(chang)閉觸(chu)(chu)(chu)頭處(chu)于閉合狀態，交(jiao)流(liu)接(jie)觸(chu)(chu)(chu)器保(bao)持吸合，電(dian)(dian)動(dong)(dong)(dong)機(ji)(ji)正(zheng)常(chang)運行。

若電(dian)動(dong)機(ji)出(chu)現過載(zai)情況，繞組中(zhong)電(dian)流(liu)增大(da)，通過熱繼電(dian)器(qi)元(yuan)件中(zhong)的電(dian)流(liu)增大(da)使雙金屬片溫(wen)度(du)升得(de)更高(gao)，彎曲程度(du)加大(da)，推動(dong)人(ren)字(zi)(zi)形撥桿，人(ren)字(zi)(zi)形撥桿推動(dong)常閉觸頭(tou)，使觸頭(tou)斷開而斷開交流(liu)接(jie)觸器(qi)線圈電(dian)路(lu)，使接(jie)觸器(qi)釋放、切斷電(dian)動(dong)機(ji)的電(dian)源，電(dian)動(dong)機(ji)停車而得(de)到保護。

螺釘(ding)8是常(chang)(chang)閉觸(chu)(chu)頭復(fu)(fu)(fu)位(wei)(wei)(wei)方(fang)式(shi)調節螺釘(ding)。當螺釘(ding)位(wei)(wei)(wei)置(zhi)靠左(zuo)時(shi)，電(dian)動(dong)(dong)機(ji)(ji)(ji)過載(zai)(zai)(zai)后(hou)，常(chang)(chang)閉觸(chu)(chu)頭斷開，電(dian)動(dong)(dong)機(ji)(ji)(ji)停車后(hou)，熱(re)繼(ji)(ji)電(dian)器(qi)雙(shuang)金屬(shu)片冷卻復(fu)(fu)(fu)位(wei)(wei)(wei)。常(chang)(chang)閉觸(chu)(chu)頭的(de)動(dong)(dong)觸(chu)(chu)頭在彈簧(huang)的(de)作用下會自動(dong)(dong)復(fu)(fu)(fu)位(wei)(wei)(wei)。此時(shi)熱(re)繼(ji)(ji)電(dian)器(qi)為自動(dong)(dong)復(fu)(fu)(fu)位(wei)(wei)(wei)狀(zhuang)態(tai)(tai)。將(jiang)螺釘(ding)逆時(shi)針旋(xuan)轉向右調到一定位(wei)(wei)(wei)置(zhi)時(shi)，若(ruo)這時(shi)電(dian)動(dong)(dong)機(ji)(ji)(ji)過載(zai)(zai)(zai)，熱(re)繼(ji)(ji)電(dian)器(qi)的(de)常(chang)(chang)閉觸(chu)(chu)頭斷開。其動(dong)(dong)觸(chu)(chu)頭將(jiang)擺(bai)到右側一新的(de)平(ping)衡位(wei)(wei)(wei)置(zhi)。電(dian)動(dong)(dong)機(ji)(ji)(ji)斷電(dian)停車后(hou)，動(dong)(dong)觸(chu)(chu)頭不能復(fu)(fu)(fu)位(wei)(wei)(wei)。必須按動(dong)(dong)復(fu)(fu)(fu)位(wei)(wei)(wei)按鈕后(hou)動(dong)(dong)觸(chu)(chu)頭方(fang)能復(fu)(fu)(fu)位(wei)(wei)(wei)。此時(shi)熱(re)繼(ji)(ji)電(dian)器(qi)為手(shou)動(dong)(dong)復(fu)(fu)(fu)位(wei)(wei)(wei)狀(zhuang)態(tai)(tai)。若(ruo)電(dian)動(dong)(dong)機(ji)(ji)(ji)過載(zai)(zai)(zai)是故障(zhang)性的(de)，為了避免(mian)再次輕易地起動(dong)(dong)電(dian)動(dong)(dong)機(ji)(ji)(ji)，熱(re)繼(ji)(ji)電(dian)器(qi)宜采(cai)用手(shou)動(dong)(dong)復(fu)(fu)(fu)位(wei)(wei)(wei)方(fang)式(shi)。若(ruo)要將(jiang)熱(re)繼(ji)(ji)電(dian)器(qi)由手(shou)動(dong)(dong)復(fu)(fu)(fu)位(wei)(wei)(wei)方(fang)式(shi)調至(zhi)自動(dong)(dong)復(fu)(fu)(fu)位(wei)(wei)(wei)方(fang)式(shi)，只需(xu)將(jiang)復(fu)(fu)(fu)位(wei)(wei)(wei)調節螺釘(ding)順時(shi)針旋(xuan)進(jin)至(zhi)適當位(wei)(wei)(wei)置(zhi)即(ji)可。

二、熱繼電器型號

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

熱(re)繼(ji)電器選型方法：

1，熱(re)繼(ji)電器的選擇應等于(yu)或大于(yu)電機的額定電流(liu)。

2，熱(re)繼電器的額(e)定電流(liu)為電動機額(e)定電流(liu)的（0.95-1.05）倍(bei)。

3，對于(yu)電(dian)機電(dian)路，熱繼電(dian)器的(de)整定(ding)電(dian)流應(ying)等于(yu)電(dian)機的(de)額定(ding)電(dian)流。

4，當熱(re)繼電器周(zhou)圍(wei)的環境溫度(du)不是35℃時，應該設定為：（95-T）/ 60平(ping)方t：環境溫度。

三、熱繼電器的作用

主要用(yong)來(lai)(lai)對異步電(dian)動機進行過載(zai)保(bao)(bao)護(hu)，他的(de)工作原理是過載(zai)電(dian)流通(tong)過熱元件后，使(shi)雙金屬片(pian)加熱彎(wan)(wan)曲去推動動作機構來(lai)(lai)帶動觸點(dian)動作，從而將電(dian)動機控制電(dian)路(lu)斷開實現電(dian)動機斷電(dian)停車，起到(dao)過載(zai)保(bao)(bao)護(hu)的(de)作用(yong)。鑒于雙金屬片(pian)受(shou)熱彎(wan)(wan)曲過程中(zhong)，熱量的(de)傳遞需(xu)要較長的(de)時間，因(yin)此，熱繼電(dian)器不(bu)能(neng)用(yong)作短(duan)路(lu)保(bao)(bao)護(hu)，而只能(neng)用(yong)作過載(zai)保(bao)(bao)護(hu)熱繼電(dian)器的(de)過載(zai)保(bao)(bao)護(hu)。

熱繼電器其(qi)它部分(fen)的(de)作(zuo)用如下(xia)：人(ren)(ren)字形撥(bo)桿(gan)的(de)左臂也(ye)用雙金屬(shu)片制成，當(dang)環境溫度發生(sheng)變(bian)化(hua)時，主電路中的(de)雙金屬(shu)片會產生(sheng)一定的(de)變(bian)形彎曲，這時人(ren)(ren)字形撥(bo)桿(gan)的(de)左臂也(ye)會發生(sheng)同方(fang)向的(de)變(bian)形彎曲，從而(er)使人(ren)(ren)字形撥(bo)桿(gan)與推桿(gan)之間的(de)距離(li)基本保(bao)持不(bu)變(bian)，保(bao)證(zheng)熱(re)繼電器動(dong)作(zuo)的(de)準確(que)性。這種作(zuo)用稱(cheng)溫度補償(chang)作(zuo)用。