電磁鐵的發明

1822年，法國物理學家阿拉戈和呂薩克發現，當電流通過其中有鐵塊的繞線時，它能使繞線中的鐵塊磁化。這實際上是寧夏電磁鐵原理的最(zui)初發(fa)現。1823年(nian)，斯(si)特金也做了一(yi)(yi)次類似的實驗：他在(zai)一(yi)(yi)根并非(fei)是(shi)磁(ci)(ci)鐵(tie)(tie)棒的U型鐵(tie)(tie)棒上(shang)繞(rao)了18圈(quan)(quan)銅裸(luo)線(xian)，當銅線(xian)與伏(fu)打(da)電池接通(tong)時，繞(rao)在(zai)U型鐵(tie)(tie)棒上(shang)的銅線(xian)圈(quan)(quan)即產生了密(mi)集(ji)的磁(ci)(ci)場(chang)，這樣就(jiu)使U型鐵(tie)(tie)棒變成(cheng)(cheng)了一(yi)(yi)塊“電磁(ci)(ci)鐵(tie)(tie)”。這種電磁(ci)(ci)鐵(tie)(tie)上(shang)的磁(ci)(ci)能要比(bi)永(yong)磁(ci)(ci)能大放多倍(bei)，它能吸(xi)起比(bi)它重20倍(bei)的鐵(tie)(tie)塊，而(er)當電源(yuan)切(qie)斷后，U型鐵(tie)(tie)棒就(jiu)什(shen)么鐵(tie)(tie)塊也吸(xi)不住，重新(xin)成(cheng)(cheng)為(wei)一(yi)(yi)根普通(tong)的鐵(tie)(tie)棒。

斯特金的電磁(ci)鐵發明(ming)，使(shi)人們看到了把電能轉化(hua)為(wei)磁(ci)能的光明(ming)前景(jing)，這一發明(ming)很快在英國、美國以及西歐一些沿(yan)海國家傳播(bo)開(kai)來。

1829年，美國電(dian)學家亨(heng)利對斯(si)特金電(dian)磁(ci)鐵(tie)裝置進行了(le)(le)(le)一些革新，絕緣導線(xian)(xian)代(dai)替裸(luo)銅(tong)導線(xian)(xian)，因此(ci)不必擔心(xin)被銅(tong)導線(xian)(xian)過分靠(kao)近而短路。由于導線(xian)(xian)有(you)了(le)(le)(le)絕緣層，就可(ke)以將(jiang)它們(men)一圈圈地緊緊地繞在一起，由于線(xian)(xian)圈越(yue)密集，產生的(de)磁(ci)場就越(yue)強，這樣就大大提(ti)高了(le)(le)(le)把電(dian)能轉化為磁(ci)能的(de)能力(li)。到了(le)(le)(le)1831年，亨(heng)利試制出了(le)(le)(le)一塊更新的(de)電(dian)磁(ci)鐵(tie)，雖然(ran)它的(de)體積并不大，但(dan)它能吸起1噸重的(de)鐵(tie)塊。

電(dian)磁鐵(tie)內部帶有鐵(tie)心的(de)(de)(de)、利用(yong)(yong)(yong)通(tong)有電(dian)流的(de)(de)(de)線(xian)(xian)圈使其像磁鐵(tie)一樣(yang)具有磁性(xing)(xing)的(de)(de)(de)裝置叫做(zuo)電(dian)磁鐵(tie)，通(tong)常制(zhi)成(cheng)條形(xing)或(huo)蹄形(xing)。鐵(tie)心要用(yong)(yong)(yong)容易磁化，又(you)容易消(xiao)失磁性(xing)(xing)的(de)(de)(de)軟(ruan)鐵(tie)或(huo)硅鋼來(lai)制(zhi)做(zuo)。這(zhe)樣(yang)的(de)(de)(de)電(dian)磁鐵(tie)在通(tong)電(dian)時有磁性(xing)(xing)，斷電(dian)后就隨之消(xiao)失。 電(dian)磁鐵(tie)有許(xu)多(duo)優點：電(dian)磁鐵(tie)磁性(xing)(xing)的(de)(de)(de)有無，可以用(yong)(yong)(yong)通(tong)、斷電(dian)流控(kong)制(zhi)。磁性(xing)(xing)的(de)(de)(de)大小可以用(yong)(yong)(yong)電(dian)流的(de)(de)(de)強弱或(huo)線(xian)(xian)圈的(de)(de)(de)匝數(shu)來(lai)控(kong)制(zhi)。

電磁鐵的主要特點

1、采(cai)用(yong)全密封(feng)結(jie)構，防潮(chao)性能好。

2、經(jing)計(ji)算機優化(hua)設計(ji)，結構合(he)理、自重輕、吸力大、能(neng)耗低(di)。

3、勵磁(ci)線圈經(jing)特別工藝處理，提高了線圈的電器和機械(xie)性能，絕緣資料熱等級到達C級，運用壽命長。

4、普通型(xing)電磁(ci)鐵的額定通電持續率由曩昔的50%提高(gao)到60%，提高(gao)了電磁(ci)鐵的運用(yong)功(gong)率。

5、超高溫(wen)型(xing)電磁鐵采用獨(du)特(te)隔熱方式，其間被(bei)吸物(wu)溫(wen)度有曩昔(xi)的(de)600℃提高700℃，擴大了電磁鐵的(de)適用范圍(wei)。

6、裝置、運轉、保護簡潔(jie)。

電磁鐵工作原理

將電(dian)(dian)磁(ci)(ci)(ci)(ci)(ci)(ci)能變換(huan)為機(ji)械(xie)(xie)能以實(shi)現吸(xi)(xi)(xi)合作(zuo)功的(de)(de)(de)一(yi)種電(dian)(dian)器。通(tong)(tong)常(chang)由軟磁(ci)(ci)(ci)(ci)(ci)(ci)材(cai)料制(zhi)成的(de)(de)(de)鐵(tie)心、銜(xian)鐵(tie)和勵(li)磁(ci)(ci)(ci)(ci)(ci)(ci)繞組(zu)組(zu)成。當勵(li)磁(ci)(ci)(ci)(ci)(ci)(ci)繞組(zu)通(tong)(tong)電(dian)(dian)時，繞組(zu)周圍產生磁(ci)(ci)(ci)(ci)(ci)(ci)場，鐵(tie)心磁(ci)(ci)(ci)(ci)(ci)(ci)化，并產生電(dian)(dian)磁(ci)(ci)(ci)(ci)(ci)(ci)吸(xi)(xi)(xi)力吸(xi)(xi)(xi)引(yin)銜(xian)鐵(tie)，使(shi)之運動作(zuo)功。電(dian)(dian)磁(ci)(ci)(ci)(ci)(ci)(ci)鐵(tie)主要(yao)用于操動、牽(qian)引(yin)機(ji)械(xie)(xie)裝置，以達到預期(qi)的(de)(de)(de)目的(de)(de)(de)。工業上(shang)常(chang)用的(de)(de)(de)電(dian)(dian)磁(ci)(ci)(ci)(ci)(ci)(ci)鐵(tie)有(you)制(zhi)動電(dian)(dian)磁(ci)(ci)(ci)(ci)(ci)(ci)鐵(tie)、牽(qian)引(yin)電(dian)(dian)磁(ci)(ci)(ci)(ci)(ci)(ci)鐵(tie)、起重電(dian)(dian)磁(ci)(ci)(ci)(ci)(ci)(ci)鐵(tie)和閥(fa)用電(dian)(dian)磁(ci)(ci)(ci)(ci)(ci)(ci)鐵(tie)等。此外，屬于電(dian)(dian)磁(ci)(ci)(ci)(ci)(ci)(ci)鐵(tie)類的(de)(de)(de)還有(you)用以傳遞或隔(ge)斷兩軸間的(de)(de)(de)機(ji)械(xie)(xie)聯(lian)系的(de)(de)(de)電(dian)(dian)磁(ci)(ci)(ci)(ci)(ci)(ci)聯(lian)軸器;用在(zai)機(ji)床(chuang)工作(zuo)臺上(shang)以吸(xi)(xi)(xi)牢磁(ci)(ci)(ci)(ci)(ci)(ci)性(xing)材(cai)料工件的(de)(de)(de)電(dian)(dian)磁(ci)(ci)(ci)(ci)(ci)(ci)吸(xi)(xi)(xi)盤(pan);供高(gao)能物理、核聚變研究、磁(ci)(ci)(ci)(ci)(ci)(ci)流體發電(dian)(dian)和高(gao)速懸浮列車等方面使(shi)用的(de)(de)(de)、能產生高(gao)達數(shu)十特（斯拉）的(de)(de)(de)磁(ci)(ci)(ci)(ci)(ci)(ci)通(tong)(tong)密(mi)度而幾(ji)乎不(bu)消耗繞組(zu)功率的(de)(de)(de)超導電(dian)(dian)磁(ci)(ci)(ci)(ci)(ci)(ci)鐵(tie)等。

起重電磁鐵

用來吊(diao)運和(he)裝卸鐵(tie)磁(ci)(ci)(ci)性(xing)物體的(de)電(dian)磁(ci)(ci)(ci)鐵(tie)。工(gong)業上(shang)常用以吊(diao)運或裝卸鐵(tie)礦(kuang)石、鐵(tie)砂、廢鋼鐵(tie)、鋼錠、鋼軌以及各種鋼材和(he)鋼質工(gong)件。起(qi)重電(dian)磁(ci)(ci)(ci)鐵(tie)通(tong)常做成圓(yuan)盤形(xing)或矩形(xing)，并帶有內磁(ci)(ci)(ci)極(ji)(ji)和(he)外磁(ci)(ci)(ci)極(ji)(ji)。當勵磁(ci)(ci)(ci)繞(rao)組通(tong)電(dian)后，內外磁(ci)(ci)(ci)極(ji)(ji)均(jun)被(bei)(bei)磁(ci)(ci)(ci)化，吸(xi)引(yin)鋼質材料(liao)或工(gong)件（相當于一(yi)般電(dian)磁(ci)(ci)(ci)鐵(tie)中(zhong)的(de)銜鐵(tie)），形(xing)成一(yi)個閉(bi)合的(de)磁(ci)(ci)(ci)路(lu)。為(wei)保護勵磁(ci)(ci)(ci)繞(rao)組，使之不因(yin)磁(ci)(ci)(ci)極(ji)(ji)與(yu)被(bei)(bei)吸(xi)引(yin)物體間(jian)的(de)機械撞擊(ji)所(suo)損傷，起(qi)重電(dian)磁(ci)(ci)(ci)鐵(tie)通(tong)常采(cai)用甲殼式(shi)結構，并且采(cai)用直流(liu)勵磁(ci)(ci)(ci)。

牽引電磁鐵

供牽(qian)引(yin)(yin)和推斥機械(xie)裝置用的(de)(de)一(yi)種電(dian)磁鐵(tie)(tie)。主要(yao)用于各種自(zi)動設備中，以(yi)實(shi)現遠距離控制(zhi)。為(wei)了能夠在(zai)長行程下獲得較大的(de)(de)電(dian)磁吸(xi)力(li)，牽(qian)引(yin)(yin)電(dian)磁鐵(tie)(tie)一(yi)般采用吸(xi)引(yin)(yin)特性(xing)比較平(ping)坦的(de)(de)甲殼式(shi)(shi)結構(gou)。其內部(bu)裝有(you)鐵(tie)(tie)心、銜鐵(tie)(tie)和勵磁線圈。使(shi)用時(shi)，將鐵(tie)(tie)心固定(ding)在(zai)機械(xie)裝置的(de)(de)靜止部(bu)件上(shang)(shang)，銜鐵(tie)(tie)則連(lian)接在(zai)牽(qian)引(yin)(yin)桿上(shang)(shang)。當(dang)勵磁繞組通電(dian)后，鐵(tie)(tie)心被磁化，產(chan)生(sheng)電(dian)磁吸(xi)力(li)吸(xi)引(yin)(yin)銜鐵(tie)(tie)，后者則通過(guo)牽(qian)引(yin)(yin)桿來(lai)操(cao)縱所控制(zhi)的(de)(de)機械(xie)裝置的(de)(de)機構(gou)。為(wei)了適應(ying)不(bu)同控制(zhi)對象的(de)(de)需(xu)要(yao)，牽(qian)引(yin)(yin)電(dian)磁鐵(tie)(tie)有(you)拉(la)動式(shi)(shi)和推動式(shi)(shi)兩(liang)種，但都不(bu)具備復位裝置。牽(qian)引(yin)(yin)電(dian)磁鐵(tie)(tie)的(de)(de)主要(yao)技術指(zhi)標為(wei)一(yi)定(ding)行程下的(de)(de)電(dian)磁吸(xi)力(li)、操(cao)作頻率和壽命(ming)。

制動電磁鐵

作機(ji)械制(zhi)(zhi)(zhi)(zhi)(zhi)動(dong)(dong)(dong)用(yong)的(de)一種電(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)鐵(tie)(tie)(tie)(tie)。主要用(yong)于電(dian)(dian)(dian)(dian)(dian)(dian)力(li)驅動(dong)(dong)(dong)裝置和起(qi)重(zhong)運輸設備中，并(bing)與(yu)(yu)制(zhi)(zhi)(zhi)(zhi)(zhi)動(dong)(dong)(dong)器(qi)(qi)配合(he)使(shi)(shi)用(yong)，使(shi)(shi)電(dian)(dian)(dian)(dian)(dian)(dian)動(dong)(dong)(dong)機(ji)準(zhun)確停車和懸吊著的(de)重(zhong)物不致(zhi)墜落。制(zhi)(zhi)(zhi)(zhi)(zhi)動(dong)(dong)(dong)電(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)鐵(tie)(tie)(tie)(tie)按(an)銜鐵(tie)(tie)(tie)(tie)行程(cheng)分為長(chang)行程(cheng)和短行程(cheng)兩類;按(an)勵(li)磁(ci)(ci)(ci)(ci)方式(shi)分為直流和交(jiao)流、并(bing)勵(li)和串勵(li)以及(ji)(ji)單相(xiang)和三相(xiang)等(deng)種類。制(zhi)(zhi)(zhi)(zhi)(zhi)動(dong)(dong)(dong)電(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)鐵(tie)(tie)(tie)(tie)的(de)工作原(yuan)理是：當電(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)鐵(tie)(tie)(tie)(tie)的(de)繞組通(tong)(tong)(tong)電(dian)(dian)(dian)(dian)(dian)(dian)后，銜鐵(tie)(tie)(tie)(tie)被(bei)吸向(xiang)鐵(tie)(tie)(tie)(tie)心，并(bing)通(tong)(tong)(tong)過制(zhi)(zhi)(zhi)(zhi)(zhi)動(dong)(dong)(dong)器(qi)(qi)中的(de)停檔壓(ya)迫制(zhi)(zhi)(zhi)(zhi)(zhi)動(dong)(dong)(dong)桿，使(shi)(shi)之移動(dong)(dong)(dong)，從而迫使(shi)(shi)制(zhi)(zhi)(zhi)(zhi)(zhi)動(dong)(dong)(dong)器(qi)(qi)松閘。切(qie)斷線圈電(dian)(dian)(dian)(dian)(dian)(dian)源后，制(zhi)(zhi)(zhi)(zhi)(zhi)動(dong)(dong)(dong)桿在彈簧作用(yong)下使(shi)(shi)銜鐵(tie)(tie)(tie)(tie)脫離磁(ci)(ci)(ci)(ci)軛，而制(zhi)(zhi)(zhi)(zhi)(zhi)動(dong)(dong)(dong)器(qi)(qi)則將(jiang)機(ji)構剎住。制(zhi)(zhi)(zhi)(zhi)(zhi)動(dong)(dong)(dong)電(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)鐵(tie)(tie)(tie)(tie)的(de)主要技術參數是行程(cheng)、一定行程(cheng)下的(de)電(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)吸力(li)、操(cao)作頻(pin)率和通(tong)(tong)(tong)電(dian)(dian)(dian)(dian)(dian)(dian)持(chi)續率。操(cao)作頻(pin)率是指(zhi)每小時操(cao)作的(de)次(ci)數;通(tong)(tong)(tong)電(dian)(dian)(dian)(dian)(dian)(dian)持(chi)續率是指(zhi)每次(ci)通(tong)(tong)(tong)電(dian)(dian)(dian)(dian)(dian)(dian)時間與(yu)(yu)每次(ci)通(tong)(tong)(tong)電(dian)(dian)(dian)(dian)(dian)(dian)及(ji)(ji)不通(tong)(tong)(tong)電(dian)(dian)(dian)(dian)(dian)(dian)時間之和的(de)百分比(bi)。使(shi)(shi)用(yong)中，制(zhi)(zhi)(zhi)(zhi)(zhi)動(dong)(dong)(dong)電(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)鐵(tie)(tie)(tie)(tie)與(yu)(yu)瓦式(shi)制(zhi)(zhi)(zhi)(zhi)(zhi)動(dong)(dong)(dong)器(qi)(qi)相(xiang)配合(he)時用(yong)短行程(cheng)類;與(yu)(yu)皮帶(dai)制(zhi)(zhi)(zhi)(zhi)(zhi)動(dong)(dong)(dong)器(qi)(qi)相(xiang)配合(he)時用(yong)長(chang)行程(cheng)類。制(zhi)(zhi)(zhi)(zhi)(zhi)動(dong)(dong)(dong)電(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)鐵(tie)(tie)(tie)(tie)通(tong)(tong)(tong)過液壓(ya)方式(shi)將(jiang)電(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)力(li)傳遞給制(zhi)(zhi)(zhi)(zhi)(zhi)動(dong)(dong)(dong)機(ji)構的(de)稱液壓(ya)制(zhi)(zhi)(zhi)(zhi)(zhi)動(dong)(dong)(dong)電(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)鐵(tie)(tie)(tie)(tie)。

閥用電磁鐵

供遠距離(li)操作(zuo)(zuo)各種液壓、氣動(dong)系統閥(fa)(fa)門的(de)電(dian)(dian)磁(ci)鐵(tie)(tie)(tie)。常用(yong)于各種金屬切(qie)削機床中。閥(fa)(fa)用(yong)電(dian)(dian)磁(ci)鐵(tie)(tie)(tie)不設復位裝(zhuang)置，而由閥(fa)(fa)體中的(de)彈簧使之復位。當電(dian)(dian)磁(ci)鐵(tie)(tie)(tie)的(de)勵(li)磁(ci)繞組通(tong)過(guo)電(dian)(dian)流時，電(dian)(dian)磁(ci)吸(xi)(xi)力(li)(li)即克服彈簧阻力(li)(li)，使閥(fa)(fa)體的(de)推(tui)桿移動(dong)，將閥(fa)(fa)門開啟;當勵(li)磁(ci)繞組斷電(dian)(dian)后，在(zai)復位彈簧作(zuo)(zuo)用(yong)下，閥(fa)(fa)體推(tui)桿便推(tui)動(dong)銜(xian)(xian)鐵(tie)(tie)(tie)，使其移動(dong)額定行程(cheng)處，閥(fa)(fa)門關(guan)閉。閥(fa)(fa)用(yong)電(dian)(dian)磁(ci)鐵(tie)(tie)(tie)分為濕(shi)式和(he)干式兩種。濕(shi)式閥(fa)(fa)用(yong)電(dian)(dian)磁(ci)鐵(tie)(tie)(tie)的(de)銜(xian)(xian)鐵(tie)(tie)(tie)在(zai)液壓油(you)(you)中工作(zuo)(zuo)，由于油(you)(you)的(de)冷卻作(zuo)(zuo)用(yong)，使其與(yu)具(ju)有(you)相同吸(xi)(xi)力(li)(li)的(de)電(dian)(dian)磁(ci)鐵(tie)(tie)(tie)相比(bi)，有(you)較小(xiao)的(de)尺寸(cun)。

電磁鐵的應用

門禁(jin)：為(wei)什么門禁(jin)可以在(zai)沒刷(shua)(shua)卡時把門牢(lao)牢(lao)的(de)(de)“抓住”？原來單元門是(shi)由(you)鋼材料做成的(de)(de)，那(nei)個金(jin)屬體(ti)在(zai)通(tong)電(dian)時可以產(chan)生(sheng)強大的(de)(de)磁(ci)(ci)場(chang)，產(chan)生(sheng)的(de)(de)磁(ci)(ci)力能(neng)把門牢(lao)牢(lao)的(de)(de)吸住，而刷(shua)(shua)卡的(de)(de)瞬間，切斷電(dian)流，金(jin)屬體(ti)失去磁(ci)(ci)性(xing)，我(wo)們就可以打開門了。那(nei)個金(jin)屬體(ti)其實是(shi)一(yi)塊電(dian)磁(ci)(ci)鐵。

電(dian)磁(ci)起重(zhong)機：最(zui)直接的應用之一是電(dian)磁(ci)起重(zhong)機。電(dian)磁(ci)鐵(tie)(tie)安裝在吊車上，通電(dian)后(hou)吸(xi)起大量鋼(gang)鐵(tie)(tie)，移動到另(ling)一個位置后(hou)切(qie)斷電(dian)流，鋼(gang)鐵(tie)(tie)被放(fang)下，免去了打捆的麻(ma)煩。大型電(dian)磁(ci)起重(zhong)機一次可以吊起幾噸(dun)鋼(gang)材。

在(zai)電(dian)(dian)動機(ji)、發(fa)電(dian)(dian)機(ji)、電(dian)(dian)鈴和電(dian)(dian)磁(ci)繼電(dian)(dian)器(qi)里也用到(dao)電(dian)(dian)磁(ci)鐵。全(quan)自動洗衣機(ji)的(de)進水(shui)、排水(shui)閥門，衛生(sheng)間里感應式沖(chong)水(shui)器(qi)的(de)閥門，也都是(shi)由電(dian)(dian)磁(ci)鐵控(kong)制(zhi)的(de)。

電磁(ci)鐵(tie)的另(ling)一個(ge)應(ying)用是產(chan)生強(qiang)磁(ci)場(chang)。現代技術中很多地方需要的強(qiang)磁(ci)場(chang)都由電磁(ci)鐵(tie)提供，如大型電動機、發電機、磁(ci)療設備等。