【熱繼電器(qi)】熱繼電器(qi)工作原理 熱繼電器(qi)型(xing)號 熱繼電器(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(qi)線路的過載保護的保護電器。

電(dian)(dian)(dian)動(dong)(dong)機(ji)(ji)(ji)(ji)在(zai)(zai)實際運行(xing)中，如拖(tuo)動(dong)(dong)生產機(ji)(ji)(ji)(ji)械進行(xing)工作過(guo)程中，若(ruo)機(ji)(ji)(ji)(ji)械出(chu)現不(bu)(bu)正常的(de)(de)(de)情(qing)況或(huo)電(dian)(dian)(dian)路異常使電(dian)(dian)(dian)動(dong)(dong)機(ji)(ji)(ji)(ji)遇(yu)到過(guo)載(zai)，則(ze)電(dian)(dian)(dian)動(dong)(dong)機(ji)(ji)(ji)(ji)轉(zhuan)速下降、繞(rao)(rao)組中的(de)(de)(de)電(dian)(dian)(dian)流(liu)將增(zeng)大(da)(da)，使電(dian)(dian)(dian)動(dong)(dong)機(ji)(ji)(ji)(ji)的(de)(de)(de)繞(rao)(rao)組溫度升(sheng)高。若(ruo)過(guo)載(zai)電(dian)(dian)(dian)流(liu)不(bu)(bu)大(da)(da)且過(guo)載(zai)的(de)(de)(de)時間較短(duan)，電(dian)(dian)(dian)動(dong)(dong)機(ji)(ji)(ji)(ji)繞(rao)(rao)組不(bu)(bu)超(chao)過(guo)允(yun)許溫升(sheng)，這種過(guo)載(zai)是允(yun)許的(de)(de)(de)。但若(ruo)過(guo)載(zai)時間長，過(guo)載(zai)電(dian)(dian)(dian)流(liu)大(da)(da)，電(dian)(dian)(dian)動(dong)(dong)機(ji)(ji)(ji)(ji)繞(rao)(rao)組的(de)(de)(de)溫升(sheng)就會(hui)超(chao)過(guo)允(yun)許值，使電(dian)(dian)(dian)動(dong)(dong)機(ji)(ji)(ji)(ji)繞(rao)(rao)組老化，縮短(duan)電(dian)(dian)(dian)動(dong)(dong)機(ji)(ji)(ji)(ji)的(de)(de)(de)使用壽(shou)命，嚴重(zhong)時甚至會(hui)使電(dian)(dian)(dian)動(dong)(dong)機(ji)(ji)(ji)(ji)繞(rao)(rao)組燒毀。所以，這種過(guo)載(zai)是電(dian)(dian)(dian)動(dong)(dong)機(ji)(ji)(ji)(ji)不(bu)(bu)能承受的(de)(de)(de)。熱(re)繼電(dian)(dian)(dian)器就是利用電(dian)(dian)(dian)流(liu)的(de)(de)(de)熱(re)效應原理，在(zai)(zai)出(chu)現電(dian)(dian)(dian)動(dong)(dong)機(ji)(ji)(ji)(ji)不(bu)(bu)能承受的(de)(de)(de)過(guo)載(zai)時切斷(duan)電(dian)(dian)(dian)動(dong)(dong)機(ji)(ji)(ji)(ji)電(dian)(dian)(dian)路，為電(dian)(dian)(dian)動(dong)(dong)機(ji)(ji)(ji)(ji)提供(gong)過(guo)載(zai)保護的(de)(de)(de)保護電(dian)(dian)(dian)器。

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使(shi)用熱繼(ji)電(dian)器對(dui)電(dian)動(dong)(dong)(dong)機進行(xing)過載保護時，將熱元件(jian)與電(dian)動(dong)(dong)(dong)機的定(ding)子繞(rao)組串聯，將熱繼(ji)電(dian)器的常(chang)(chang)(chang)閉(bi)觸(chu)(chu)(chu)頭(tou)串聯在交流(liu)(liu)接(jie)觸(chu)(chu)(chu)器的電(dian)磁線圈的控制電(dian)路中，并(bing)調節(jie)整定(ding)電(dian)流(liu)(liu)調節(jie)旋鈕(niu)，使(shi)人字形(xing)(xing)撥桿(gan)(gan)與推(tui)桿(gan)(gan)相距一(yi)適當距離(li)。當電(dian)動(dong)(dong)(dong)機正常(chang)(chang)(chang)工作(zuo)時，通過熱元件(jian)的電(dian)流(liu)(liu)即為電(dian)動(dong)(dong)(dong)機的額定(ding)電(dian)流(liu)(liu)，熱元件(jian)發熱，雙金屬片受(shou)熱后彎曲，使(shi)推(tui)桿(gan)(gan)剛好(hao)與人字形(xing)(xing)撥桿(gan)(gan)接(jie)觸(chu)(chu)(chu)，而又不能(neng)推(tui)動(dong)(dong)(dong)人字形(xing)(xing)撥桿(gan)(gan)。常(chang)(chang)(chang)閉(bi)觸(chu)(chu)(chu)頭(tou)處于閉(bi)合狀態，交流(liu)(liu)接(jie)觸(chu)(chu)(chu)器保持吸合，電(dian)動(dong)(dong)(dong)機正常(chang)(chang)(chang)運行(xing)。

若(ruo)電(dian)動(dong)機出現過載情況，繞(rao)組中(zhong)電(dian)流(liu)增(zeng)大，通過熱繼(ji)電(dian)器元件中(zhong)的電(dian)流(liu)增(zeng)大使(shi)雙(shuang)金屬片溫度(du)升得更高，彎曲程度(du)加大，推動(dong)人(ren)字形撥桿(gan)(gan)，人(ren)字形撥桿(gan)(gan)推動(dong)常閉觸頭(tou)，使(shi)觸頭(tou)斷開(kai)而(er)斷開(kai)交流(liu)接觸器線圈電(dian)路，使(shi)接觸器釋放(fang)、切斷電(dian)動(dong)機的電(dian)源，電(dian)動(dong)機停(ting)車而(er)得到保(bao)護。

螺釘8是常(chang)閉觸(chu)(chu)頭(tou)(tou)(tou)(tou)復(fu)(fu)(fu)(fu)位(wei)(wei)方式(shi)調(diao)(diao)節(jie)螺釘。當(dang)(dang)螺釘位(wei)(wei)置(zhi)靠(kao)左時(shi)(shi)，電(dian)(dian)(dian)(dian)動(dong)(dong)(dong)(dong)機(ji)過載后，常(chang)閉觸(chu)(chu)頭(tou)(tou)(tou)(tou)斷(duan)開，電(dian)(dian)(dian)(dian)動(dong)(dong)(dong)(dong)機(ji)停車后，熱繼(ji)(ji)電(dian)(dian)(dian)(dian)器(qi)雙金(jin)屬片(pian)冷卻(que)復(fu)(fu)(fu)(fu)位(wei)(wei)。常(chang)閉觸(chu)(chu)頭(tou)(tou)(tou)(tou)的(de)動(dong)(dong)(dong)(dong)觸(chu)(chu)頭(tou)(tou)(tou)(tou)在彈簧的(de)作用下會(hui)自(zi)動(dong)(dong)(dong)(dong)復(fu)(fu)(fu)(fu)位(wei)(wei)。此(ci)時(shi)(shi)熱繼(ji)(ji)電(dian)(dian)(dian)(dian)器(qi)為自(zi)動(dong)(dong)(dong)(dong)復(fu)(fu)(fu)(fu)位(wei)(wei)狀(zhuang)(zhuang)態(tai)。將(jiang)螺釘逆(ni)時(shi)(shi)針旋轉向右(you)(you)調(diao)(diao)到一定(ding)位(wei)(wei)置(zhi)時(shi)(shi)，若這時(shi)(shi)電(dian)(dian)(dian)(dian)動(dong)(dong)(dong)(dong)機(ji)過載，熱繼(ji)(ji)電(dian)(dian)(dian)(dian)器(qi)的(de)常(chang)閉觸(chu)(chu)頭(tou)(tou)(tou)(tou)斷(duan)開。其動(dong)(dong)(dong)(dong)觸(chu)(chu)頭(tou)(tou)(tou)(tou)將(jiang)擺到右(you)(you)側一新的(de)平衡位(wei)(wei)置(zhi)。電(dian)(dian)(dian)(dian)動(dong)(dong)(dong)(dong)機(ji)斷(duan)電(dian)(dian)(dian)(dian)停車后，動(dong)(dong)(dong)(dong)觸(chu)(chu)頭(tou)(tou)(tou)(tou)不(bu)能(neng)復(fu)(fu)(fu)(fu)位(wei)(wei)。必須按(an)動(dong)(dong)(dong)(dong)復(fu)(fu)(fu)(fu)位(wei)(wei)按(an)鈕后動(dong)(dong)(dong)(dong)觸(chu)(chu)頭(tou)(tou)(tou)(tou)方能(neng)復(fu)(fu)(fu)(fu)位(wei)(wei)。此(ci)時(shi)(shi)熱繼(ji)(ji)電(dian)(dian)(dian)(dian)器(qi)為手動(dong)(dong)(dong)(dong)復(fu)(fu)(fu)(fu)位(wei)(wei)狀(zhuang)(zhuang)態(tai)。若電(dian)(dian)(dian)(dian)動(dong)(dong)(dong)(dong)機(ji)過載是故障性的(de)，為了避免再次輕易地起動(dong)(dong)(dong)(dong)電(dian)(dian)(dian)(dian)動(dong)(dong)(dong)(dong)機(ji)，熱繼(ji)(ji)電(dian)(dian)(dian)(dian)器(qi)宜采用手動(dong)(dong)(dong)(dong)復(fu)(fu)(fu)(fu)位(wei)(wei)方式(shi)。若要將(jiang)熱繼(ji)(ji)電(dian)(dian)(dian)(dian)器(qi)由手動(dong)(dong)(dong)(dong)復(fu)(fu)(fu)(fu)位(wei)(wei)方式(shi)調(diao)(diao)至自(zi)動(dong)(dong)(dong)(dong)復(fu)(fu)(fu)(fu)位(wei)(wei)方式(shi)，只需將(jiang)復(fu)(fu)(fu)(fu)位(wei)(wei)調(diao)(diao)節(jie)螺釘順(shun)時(shi)(shi)針旋進(jin)至適當(dang)(dang)位(wei)(wei)置(zhi)即可。

二、熱繼電器型號

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

熱繼電器(qi)選型方法：

1，熱繼(ji)電器的(de)選(xuan)擇應等于(yu)或大于(yu)電機的(de)額定電流。

2，熱繼電器的額(e)(e)定(ding)電流(liu)為電動機額(e)(e)定(ding)電流(liu)的（0.95-1.05）倍。

3，對于電(dian)(dian)機電(dian)(dian)路，熱繼(ji)電(dian)(dian)器的(de)整定電(dian)(dian)流應等于電(dian)(dian)機的(de)額(e)定電(dian)(dian)流。

4，當熱繼電器周圍的環境溫度不是35℃時(shi)，應該設定(ding)為：（95-T）/ 60平方(fang)t：環(huan)境溫度。

三、熱繼電器的作用

主(zhu)要用(yong)(yong)(yong)來(lai)(lai)對異步(bu)電(dian)(dian)動(dong)(dong)(dong)機進(jin)行過載(zai)保(bao)護，他的(de)工作(zuo)原理是(shi)過載(zai)電(dian)(dian)流通過熱(re)元(yuan)件后，使雙(shuang)金屬片加熱(re)彎曲去推動(dong)(dong)(dong)動(dong)(dong)(dong)作(zuo)機構來(lai)(lai)帶動(dong)(dong)(dong)觸點動(dong)(dong)(dong)作(zuo)，從而將電(dian)(dian)動(dong)(dong)(dong)機控制(zhi)電(dian)(dian)路斷(duan)開實(shi)現電(dian)(dian)動(dong)(dong)(dong)機斷(duan)電(dian)(dian)停車，起到過載(zai)保(bao)護的(de)作(zuo)用(yong)(yong)(yong)。鑒于雙(shuang)金屬片受熱(re)彎曲過程(cheng)中，熱(re)量的(de)傳遞需要較長(chang)的(de)時間(jian)，因此，熱(re)繼(ji)電(dian)(dian)器不能(neng)用(yong)(yong)(yong)作(zuo)短路保(bao)護，而只(zhi)能(neng)用(yong)(yong)(yong)作(zuo)過載(zai)保(bao)護熱(re)繼(ji)電(dian)(dian)器的(de)過載(zai)保(bao)護。

熱繼電器其(qi)它部分的(de)(de)作(zuo)用(yong)如下：人字形(xing)(xing)撥桿(gan)的(de)(de)左臂(bei)也(ye)用(yong)雙金屬片制(zhi)成，當環境溫度(du)(du)發生變化時，主電路中的(de)(de)雙金屬片會(hui)產生一定的(de)(de)變形(xing)(xing)彎(wan)曲(qu)，這時人字形(xing)(xing)撥桿(gan)的(de)(de)左臂(bei)也(ye)會(hui)發生同(tong)方向的(de)(de)變形(xing)(xing)彎(wan)曲(qu)，從而使人字形(xing)(xing)撥桿(gan)與推(tui)桿(gan)之間(jian)的(de)(de)距離(li)基本保持不變，保證熱繼電器動作(zuo)的(de)(de)準確性(xing)。這種作(zuo)用(yong)稱溫度(du)(du)補(bu)償作(zuo)用(yong)。