【熱(re)繼電(dian)(dian)器(qi)】熱(re)繼電(dian)(dian)器(qi)工作原理 熱(re)繼電(dian)(dian)器(qi)型號 熱(re)繼電(dian)(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(dian)氣線路的過載保護的保護電(dian)器。

電(dian)(dian)(dian)(dian)動(dong)(dong)機(ji)(ji)(ji)在實際運(yun)行(xing)中，如(ru)拖動(dong)(dong)生(sheng)產機(ji)(ji)(ji)械進行(xing)工作過(guo)(guo)程中，若(ruo)(ruo)機(ji)(ji)(ji)械出(chu)現不(bu)正常的(de)(de)情況或電(dian)(dian)(dian)(dian)路(lu)異常使(shi)(shi)電(dian)(dian)(dian)(dian)動(dong)(dong)機(ji)(ji)(ji)遇到過(guo)(guo)載(zai)(zai)(zai)，則電(dian)(dian)(dian)(dian)動(dong)(dong)機(ji)(ji)(ji)轉(zhuan)速下降、繞(rao)組(zu)中的(de)(de)電(dian)(dian)(dian)(dian)流(liu)將增大(da)，使(shi)(shi)電(dian)(dian)(dian)(dian)動(dong)(dong)機(ji)(ji)(ji)的(de)(de)繞(rao)組(zu)溫度升高。若(ruo)(ruo)過(guo)(guo)載(zai)(zai)(zai)電(dian)(dian)(dian)(dian)流(liu)不(bu)大(da)且(qie)過(guo)(guo)載(zai)(zai)(zai)的(de)(de)時(shi)間較短(duan)，電(dian)(dian)(dian)(dian)動(dong)(dong)機(ji)(ji)(ji)繞(rao)組(zu)不(bu)超過(guo)(guo)允許(xu)溫升，這(zhe)種(zhong)過(guo)(guo)載(zai)(zai)(zai)是允許(xu)的(de)(de)。但若(ruo)(ruo)過(guo)(guo)載(zai)(zai)(zai)時(shi)間長，過(guo)(guo)載(zai)(zai)(zai)電(dian)(dian)(dian)(dian)流(liu)大(da)，電(dian)(dian)(dian)(dian)動(dong)(dong)機(ji)(ji)(ji)繞(rao)組(zu)的(de)(de)溫升就會超過(guo)(guo)允許(xu)值，使(shi)(shi)電(dian)(dian)(dian)(dian)動(dong)(dong)機(ji)(ji)(ji)繞(rao)組(zu)老(lao)化，縮短(duan)電(dian)(dian)(dian)(dian)動(dong)(dong)機(ji)(ji)(ji)的(de)(de)使(shi)(shi)用壽(shou)命(ming)，嚴重時(shi)甚至(zhi)會使(shi)(shi)電(dian)(dian)(dian)(dian)動(dong)(dong)機(ji)(ji)(ji)繞(rao)組(zu)燒毀。所以，這(zhe)種(zhong)過(guo)(guo)載(zai)(zai)(zai)是電(dian)(dian)(dian)(dian)動(dong)(dong)機(ji)(ji)(ji)不(bu)能承受的(de)(de)。熱繼電(dian)(dian)(dian)(dian)器就是利用電(dian)(dian)(dian)(dian)流(liu)的(de)(de)熱效應原理，在出(chu)現電(dian)(dian)(dian)(dian)動(dong)(dong)機(ji)(ji)(ji)不(bu)能承受的(de)(de)過(guo)(guo)載(zai)(zai)(zai)時(shi)切斷電(dian)(dian)(dian)(dian)動(dong)(dong)機(ji)(ji)(ji)電(dian)(dian)(dian)(dian)路(lu)，為電(dian)(dian)(dian)(dian)動(dong)(dong)機(ji)(ji)(ji)提供過(guo)(guo)載(zai)(zai)(zai)保護的(de)(de)保護電(dian)(dian)(dian)(dian)器。

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使(shi)用熱(re)繼電(dian)(dian)器(qi)對(dui)電(dian)(dian)動機(ji)進行過載保(bao)護時(shi)，將熱(re)元(yuan)件與(yu)電(dian)(dian)動機(ji)的(de)(de)定(ding)子(zi)繞(rao)組串(chuan)聯(lian)(lian)，將熱(re)繼電(dian)(dian)器(qi)的(de)(de)常(chang)閉(bi)(bi)(bi)觸(chu)頭(tou)串(chuan)聯(lian)(lian)在交流(liu)接(jie)觸(chu)器(qi)的(de)(de)電(dian)(dian)磁線圈(quan)的(de)(de)控制電(dian)(dian)路中，并調(diao)節整定(ding)電(dian)(dian)流(liu)調(diao)節旋鈕，使(shi)人(ren)字形撥桿(gan)與(yu)推桿(gan)相距一適當距離。當電(dian)(dian)動機(ji)正常(chang)工作時(shi)，通過熱(re)元(yuan)件的(de)(de)電(dian)(dian)流(liu)即為電(dian)(dian)動機(ji)的(de)(de)額(e)定(ding)電(dian)(dian)流(liu)，熱(re)元(yuan)件發熱(re)，雙金屬片受熱(re)后(hou)彎曲，使(shi)推桿(gan)剛好(hao)與(yu)人(ren)字形撥桿(gan)接(jie)觸(chu)，而又不(bu)能推動人(ren)字形撥桿(gan)。常(chang)閉(bi)(bi)(bi)觸(chu)頭(tou)處(chu)于閉(bi)(bi)(bi)合(he)(he)狀態，交流(liu)接(jie)觸(chu)器(qi)保(bao)持吸合(he)(he)，電(dian)(dian)動機(ji)正常(chang)運行。

若電(dian)動(dong)機出(chu)現過載情況(kuang)，繞組中電(dian)流增(zeng)大(da)，通過熱繼電(dian)器(qi)元件中的電(dian)流增(zeng)大(da)使雙金屬片溫度(du)升得(de)更高，彎(wan)曲(qu)程度(du)加大(da)，推動(dong)人字(zi)形(xing)撥桿，人字(zi)形(xing)撥桿推動(dong)常閉觸頭，使觸頭斷開(kai)而斷開(kai)交流接觸器(qi)線圈電(dian)路，使接觸器(qi)釋放、切斷電(dian)動(dong)機的電(dian)源，電(dian)動(dong)機停(ting)車(che)而得(de)到(dao)保(bao)護。

螺釘(ding)8是(shi)常(chang)閉觸(chu)(chu)(chu)頭(tou)復(fu)(fu)位方式調(diao)(diao)節(jie)螺釘(ding)。當(dang)螺釘(ding)位置靠(kao)左時(shi)，電(dian)(dian)(dian)動機(ji)過(guo)載后，常(chang)閉觸(chu)(chu)(chu)頭(tou)斷開(kai)，電(dian)(dian)(dian)動機(ji)停車后，熱(re)(re)繼(ji)電(dian)(dian)(dian)器雙金屬片冷卻復(fu)(fu)位。常(chang)閉觸(chu)(chu)(chu)頭(tou)的(de)(de)(de)動觸(chu)(chu)(chu)頭(tou)在(zai)彈簧的(de)(de)(de)作用下(xia)會(hui)自動復(fu)(fu)位。此時(shi)熱(re)(re)繼(ji)電(dian)(dian)(dian)器為(wei)(wei)自動復(fu)(fu)位狀(zhuang)態。將(jiang)螺釘(ding)逆(ni)時(shi)針旋轉向右調(diao)(diao)到一定位置時(shi)，若(ruo)這時(shi)電(dian)(dian)(dian)動機(ji)過(guo)載，熱(re)(re)繼(ji)電(dian)(dian)(dian)器的(de)(de)(de)常(chang)閉觸(chu)(chu)(chu)頭(tou)斷開(kai)。其動觸(chu)(chu)(chu)頭(tou)將(jiang)擺到右側一新的(de)(de)(de)平衡位置。電(dian)(dian)(dian)動機(ji)斷電(dian)(dian)(dian)停車后，動觸(chu)(chu)(chu)頭(tou)不能復(fu)(fu)位。必須按動復(fu)(fu)位按鈕(niu)后動觸(chu)(chu)(chu)頭(tou)方能復(fu)(fu)位。此時(shi)熱(re)(re)繼(ji)電(dian)(dian)(dian)器為(wei)(wei)手動復(fu)(fu)位狀(zhuang)態。若(ruo)電(dian)(dian)(dian)動機(ji)過(guo)載是(shi)故障性(xing)的(de)(de)(de)，為(wei)(wei)了避(bi)免再次輕易地(di)起動電(dian)(dian)(dian)動機(ji)，熱(re)(re)繼(ji)電(dian)(dian)(dian)器宜采用手動復(fu)(fu)位方式。若(ruo)要將(jiang)熱(re)(re)繼(ji)電(dian)(dian)(dian)器由(you)手動復(fu)(fu)位方式調(diao)(diao)至(zhi)自動復(fu)(fu)位方式，只需將(jiang)復(fu)(fu)位調(diao)(diao)節(jie)螺釘(ding)順時(shi)針旋進至(zhi)適當(dang)位置即(ji)可(ke)。

二、熱繼電器型號

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

熱繼電(dian)器(qi)選(xuan)型方法：

1，熱(re)繼電器的選擇(ze)應等(deng)于或(huo)大于電機的額(e)定電流。

2，熱(re)繼電(dian)(dian)器的(de)額(e)(e)定電(dian)(dian)流為電(dian)(dian)動機額(e)(e)定電(dian)(dian)流的(de)（0.95-1.05）倍。

3，對于電(dian)機電(dian)路(lu)，熱繼電(dian)器(qi)的(de)整定(ding)電(dian)流(liu)應等于電(dian)機的(de)額定(ding)電(dian)流(liu)。

4，當熱繼電器周圍的環境溫度不(bu)是35℃時，應該(gai)設定為：（95-T）/ 60平方(fang)t：環境溫度。

三、熱繼電器的作用

主(zhu)要(yao)用(yong)(yong)來對異步(bu)電(dian)(dian)動(dong)(dong)機進(jin)行過(guo)載保(bao)(bao)護，他的(de)(de)工(gong)作(zuo)(zuo)原理(li)是過(guo)載電(dian)(dian)流(liu)通過(guo)熱(re)(re)元件后，使雙金屬(shu)片加熱(re)(re)彎曲去(qu)推動(dong)(dong)動(dong)(dong)作(zuo)(zuo)機構(gou)來帶動(dong)(dong)觸點動(dong)(dong)作(zuo)(zuo)，從(cong)而將電(dian)(dian)動(dong)(dong)機控制電(dian)(dian)路斷開實(shi)現電(dian)(dian)動(dong)(dong)機斷電(dian)(dian)停車(che)，起到過(guo)載保(bao)(bao)護的(de)(de)作(zuo)(zuo)用(yong)(yong)。鑒于雙金屬(shu)片受(shou)熱(re)(re)彎曲過(guo)程中，熱(re)(re)量的(de)(de)傳遞需(xu)要(yao)較長的(de)(de)時間，因此，熱(re)(re)繼電(dian)(dian)器不能用(yong)(yong)作(zuo)(zuo)短(duan)路保(bao)(bao)護，而只(zhi)能用(yong)(yong)作(zuo)(zuo)過(guo)載保(bao)(bao)護熱(re)(re)繼電(dian)(dian)器的(de)(de)過(guo)載保(bao)(bao)護。

熱繼電器其(qi)它部分的(de)作(zuo)用(yong)(yong)如(ru)下：人字形撥桿(gan)(gan)的(de)左(zuo)臂(bei)也用(yong)(yong)雙金(jin)(jin)屬片制成，當(dang)環境溫(wen)度發生(sheng)變(bian)化時，主電路中的(de)雙金(jin)(jin)屬片會產生(sheng)一定(ding)的(de)變(bian)形彎曲(qu)，這(zhe)時人字形撥桿(gan)(gan)的(de)左(zuo)臂(bei)也會發生(sheng)同方向的(de)變(bian)形彎曲(qu)，從(cong)而使(shi)人字形撥桿(gan)(gan)與推桿(gan)(gan)之間的(de)距離基本保(bao)(bao)持不變(bian)，保(bao)(bao)證熱繼電器動作(zuo)的(de)準確(que)性(xing)。這(zhe)種作(zuo)用(yong)(yong)稱(cheng)溫(wen)度補償(chang)作(zuo)用(yong)(yong)。