【熱(re)繼(ji)電器(qi)】熱(re)繼(ji)電器(qi)工作(zuo)原理 熱(re)繼(ji)電器(qi)型(xing)號 熱(re)繼(ji)電器(qi)的作(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、電氣(qi)線路的過載保護的保護電器。

電(dian)(dian)(dian)(dian)(dian)動(dong)(dong)(dong)機(ji)(ji)(ji)(ji)在實際運行中，如拖(tuo)動(dong)(dong)(dong)生產機(ji)(ji)(ji)(ji)械進行工作過(guo)程中，若機(ji)(ji)(ji)(ji)械出現不正常的(de)(de)情況或電(dian)(dian)(dian)(dian)(dian)路異常使(shi)(shi)電(dian)(dian)(dian)(dian)(dian)動(dong)(dong)(dong)機(ji)(ji)(ji)(ji)遇到過(guo)載(zai)(zai)，則電(dian)(dian)(dian)(dian)(dian)動(dong)(dong)(dong)機(ji)(ji)(ji)(ji)轉速下降、繞(rao)(rao)組(zu)中的(de)(de)電(dian)(dian)(dian)(dian)(dian)流將增大(da)，使(shi)(shi)電(dian)(dian)(dian)(dian)(dian)動(dong)(dong)(dong)機(ji)(ji)(ji)(ji)的(de)(de)繞(rao)(rao)組(zu)溫度升高(gao)。若過(guo)載(zai)(zai)電(dian)(dian)(dian)(dian)(dian)流不大(da)且過(guo)載(zai)(zai)的(de)(de)時(shi)間較短，電(dian)(dian)(dian)(dian)(dian)動(dong)(dong)(dong)機(ji)(ji)(ji)(ji)繞(rao)(rao)組(zu)不超(chao)過(guo)允(yun)許(xu)溫升，這種過(guo)載(zai)(zai)是(shi)(shi)允(yun)許(xu)的(de)(de)。但若過(guo)載(zai)(zai)時(shi)間長，過(guo)載(zai)(zai)電(dian)(dian)(dian)(dian)(dian)流大(da)，電(dian)(dian)(dian)(dian)(dian)動(dong)(dong)(dong)機(ji)(ji)(ji)(ji)繞(rao)(rao)組(zu)的(de)(de)溫升就會超(chao)過(guo)允(yun)許(xu)值，使(shi)(shi)電(dian)(dian)(dian)(dian)(dian)動(dong)(dong)(dong)機(ji)(ji)(ji)(ji)繞(rao)(rao)組(zu)老化，縮短電(dian)(dian)(dian)(dian)(dian)動(dong)(dong)(dong)機(ji)(ji)(ji)(ji)的(de)(de)使(shi)(shi)用(yong)壽命，嚴重時(shi)甚至會使(shi)(shi)電(dian)(dian)(dian)(dian)(dian)動(dong)(dong)(dong)機(ji)(ji)(ji)(ji)繞(rao)(rao)組(zu)燒毀。所以(yi)，這種過(guo)載(zai)(zai)是(shi)(shi)電(dian)(dian)(dian)(dian)(dian)動(dong)(dong)(dong)機(ji)(ji)(ji)(ji)不能承受的(de)(de)。熱繼(ji)電(dian)(dian)(dian)(dian)(dian)器(qi)就是(shi)(shi)利用(yong)電(dian)(dian)(dian)(dian)(dian)流的(de)(de)熱效(xiao)應原理，在出現電(dian)(dian)(dian)(dian)(dian)動(dong)(dong)(dong)機(ji)(ji)(ji)(ji)不能承受的(de)(de)過(guo)載(zai)(zai)時(shi)切斷電(dian)(dian)(dian)(dian)(dian)動(dong)(dong)(dong)機(ji)(ji)(ji)(ji)電(dian)(dian)(dian)(dian)(dian)路，為電(dian)(dian)(dian)(dian)(dian)動(dong)(dong)(dong)機(ji)(ji)(ji)(ji)提供過(guo)載(zai)(zai)保護的(de)(de)保護電(dian)(dian)(dian)(dian)(dian)器(qi)。

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使用(yong)熱(re)(re)繼電(dian)(dian)(dian)器(qi)對(dui)電(dian)(dian)(dian)動(dong)(dong)機(ji)進(jin)行(xing)過載保護時，將熱(re)(re)元(yuan)(yuan)件(jian)與(yu)電(dian)(dian)(dian)動(dong)(dong)機(ji)的(de)定子繞組(zu)串聯，將熱(re)(re)繼電(dian)(dian)(dian)器(qi)的(de)常閉觸頭(tou)串聯在交流接觸器(qi)的(de)電(dian)(dian)(dian)磁線圈的(de)控制電(dian)(dian)(dian)路中，并調節整定電(dian)(dian)(dian)流調節旋鈕，使人字(zi)形撥桿(gan)與(yu)推桿(gan)相距(ju)一適當距(ju)離。當電(dian)(dian)(dian)動(dong)(dong)機(ji)正常工(gong)作時，通過熱(re)(re)元(yuan)(yuan)件(jian)的(de)電(dian)(dian)(dian)流即為(wei)電(dian)(dian)(dian)動(dong)(dong)機(ji)的(de)額定電(dian)(dian)(dian)流，熱(re)(re)元(yuan)(yuan)件(jian)發熱(re)(re)，雙金屬(shu)片受(shou)熱(re)(re)后彎曲，使推桿(gan)剛好與(yu)人字(zi)形撥桿(gan)接觸，而又不(bu)能推動(dong)(dong)人字(zi)形撥桿(gan)。常閉觸頭(tou)處于(yu)閉合狀態，交流接觸器(qi)保持吸合，電(dian)(dian)(dian)動(dong)(dong)機(ji)正常運(yun)行(xing)。

若電(dian)動(dong)(dong)機出現過載情況，繞組中電(dian)流增大，通過熱繼電(dian)器(qi)元件中的電(dian)流增大使雙金屬片溫度升得(de)更(geng)高，彎曲程度加大，推(tui)動(dong)(dong)人字形撥桿(gan)，人字形撥桿(gan)推(tui)動(dong)(dong)常閉觸(chu)頭，使觸(chu)頭斷(duan)(duan)開(kai)而(er)斷(duan)(duan)開(kai)交(jiao)流接(jie)觸(chu)器(qi)線(xian)圈電(dian)路，使接(jie)觸(chu)器(qi)釋放、切斷(duan)(duan)電(dian)動(dong)(dong)機的電(dian)源，電(dian)動(dong)(dong)機停車而(er)得(de)到(dao)保護。

螺(luo)釘(ding)8是(shi)常(chang)閉觸(chu)(chu)頭(tou)(tou)(tou)復(fu)(fu)位方式調節螺(luo)釘(ding)。當(dang)螺(luo)釘(ding)位置靠左時(shi)，電(dian)(dian)動(dong)(dong)(dong)(dong)機(ji)(ji)過(guo)載后，常(chang)閉觸(chu)(chu)頭(tou)(tou)(tou)斷開(kai)，電(dian)(dian)動(dong)(dong)(dong)(dong)機(ji)(ji)停車后，熱(re)繼(ji)(ji)電(dian)(dian)器(qi)(qi)雙金屬(shu)片冷(leng)卻復(fu)(fu)位。常(chang)閉觸(chu)(chu)頭(tou)(tou)(tou)的(de)動(dong)(dong)(dong)(dong)觸(chu)(chu)頭(tou)(tou)(tou)在(zai)彈簧的(de)作用下會自(zi)動(dong)(dong)(dong)(dong)復(fu)(fu)位。此時(shi)熱(re)繼(ji)(ji)電(dian)(dian)器(qi)(qi)為自(zi)動(dong)(dong)(dong)(dong)復(fu)(fu)位狀態。將(jiang)(jiang)螺(luo)釘(ding)逆時(shi)針旋(xuan)轉向右(you)調到一(yi)定(ding)位置時(shi)，若這時(shi)電(dian)(dian)動(dong)(dong)(dong)(dong)機(ji)(ji)過(guo)載，熱(re)繼(ji)(ji)電(dian)(dian)器(qi)(qi)的(de)常(chang)閉觸(chu)(chu)頭(tou)(tou)(tou)斷開(kai)。其動(dong)(dong)(dong)(dong)觸(chu)(chu)頭(tou)(tou)(tou)將(jiang)(jiang)擺(bai)到右(you)側一(yi)新的(de)平衡位置。電(dian)(dian)動(dong)(dong)(dong)(dong)機(ji)(ji)斷電(dian)(dian)停車后，動(dong)(dong)(dong)(dong)觸(chu)(chu)頭(tou)(tou)(tou)不能復(fu)(fu)位。必(bi)須按(an)動(dong)(dong)(dong)(dong)復(fu)(fu)位按(an)鈕后動(dong)(dong)(dong)(dong)觸(chu)(chu)頭(tou)(tou)(tou)方能復(fu)(fu)位。此時(shi)熱(re)繼(ji)(ji)電(dian)(dian)器(qi)(qi)為手(shou)動(dong)(dong)(dong)(dong)復(fu)(fu)位狀態。若電(dian)(dian)動(dong)(dong)(dong)(dong)機(ji)(ji)過(guo)載是(shi)故障性的(de)，為了(le)避(bi)免再次(ci)輕(qing)易地(di)起(qi)動(dong)(dong)(dong)(dong)電(dian)(dian)動(dong)(dong)(dong)(dong)機(ji)(ji)，熱(re)繼(ji)(ji)電(dian)(dian)器(qi)(qi)宜采(cai)用手(shou)動(dong)(dong)(dong)(dong)復(fu)(fu)位方式。若要將(jiang)(jiang)熱(re)繼(ji)(ji)電(dian)(dian)器(qi)(qi)由手(shou)動(dong)(dong)(dong)(dong)復(fu)(fu)位方式調至自(zi)動(dong)(dong)(dong)(dong)復(fu)(fu)位方式，只需(xu)將(jiang)(jiang)復(fu)(fu)位調節螺(luo)釘(ding)順時(shi)針旋(xuan)進至適當(dang)位置即可。

二、熱繼電器型號

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

熱繼電器選型方法：

1，熱繼(ji)電(dian)器的選擇應(ying)等于(yu)或大于(yu)電(dian)機的額定(ding)電(dian)流。

2，熱繼電(dian)器的額定電(dian)流為電(dian)動機額定電(dian)流的（0.95-1.05）倍。

3，對于電機電路，熱繼(ji)電器的整定(ding)電流應等(deng)于電機的額定(ding)電流。

4，當熱(re)繼電器(qi)周圍的(de)環境溫度(du)不是35℃時，應該設定為：（95-T）/ 60平方(fang)t：環(huan)境溫度。

三、熱繼電器的作用

主要(yao)(yao)用來對異步電(dian)(dian)動(dong)(dong)機(ji)進(jin)行(xing)過(guo)載(zai)(zai)保護(hu)(hu)(hu)，他的工(gong)作(zuo)(zuo)原理是(shi)過(guo)載(zai)(zai)電(dian)(dian)流通過(guo)熱元件后，使雙金(jin)屬(shu)片(pian)加(jia)熱彎(wan)曲(qu)去(qu)推動(dong)(dong)動(dong)(dong)作(zuo)(zuo)機(ji)構來帶動(dong)(dong)觸點動(dong)(dong)作(zuo)(zuo)，從而將(jiang)電(dian)(dian)動(dong)(dong)機(ji)控制電(dian)(dian)路(lu)斷開實現電(dian)(dian)動(dong)(dong)機(ji)斷電(dian)(dian)停車，起到(dao)過(guo)載(zai)(zai)保護(hu)(hu)(hu)的作(zuo)(zuo)用。鑒于(yu)雙金(jin)屬(shu)片(pian)受熱彎(wan)曲(qu)過(guo)程中，熱量的傳遞需(xu)要(yao)(yao)較長(chang)的時間(jian)，因(yin)此，熱繼(ji)電(dian)(dian)器(qi)不能用作(zuo)(zuo)短路(lu)保護(hu)(hu)(hu)，而只能用作(zuo)(zuo)過(guo)載(zai)(zai)保護(hu)(hu)(hu)熱繼(ji)電(dian)(dian)器(qi)的過(guo)載(zai)(zai)保護(hu)(hu)(hu)。

熱繼電器其它(ta)部分(fen)的(de)作用(yong)如下：人字(zi)形(xing)撥(bo)(bo)桿(gan)的(de)左臂也用(yong)雙金屬(shu)片制(zhi)成(cheng)，當環境(jing)溫度發(fa)生變(bian)化時(shi)，主電路中的(de)雙金屬(shu)片會產生一(yi)定的(de)變(bian)形(xing)彎(wan)(wan)曲，這時(shi)人字(zi)形(xing)撥(bo)(bo)桿(gan)的(de)左臂也會發(fa)生同方(fang)向的(de)變(bian)形(xing)彎(wan)(wan)曲，從(cong)而使人字(zi)形(xing)撥(bo)(bo)桿(gan)與(yu)推桿(gan)之間的(de)距離基本保持不變(bian)，保證(zheng)熱(re)繼(ji)電器動作的(de)準確性。這種(zhong)作用(yong)稱溫度補償作用(yong)。