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。這實際上是揭陽電磁鐵原(yuan)理的最初發(fa)現。1823年，斯特金(jin)也做(zuo)了(le)一(yi)次類似(si)的實驗：他在一(yi)根并非(fei)是磁鐵(tie)棒(bang)(bang)的U型鐵(tie)棒(bang)(bang)上(shang)繞了(le)18圈(quan)銅(tong)(tong)裸線，當(dang)(dang)銅(tong)(tong)線與伏(fu)打電(dian)池接通時(shi)，繞在U型鐵(tie)棒(bang)(bang)上(shang)的銅(tong)(tong)線圈(quan)即產生了(le)密集的磁場(chang)，這(zhe)樣就使U型鐵(tie)棒(bang)(bang)變成了(le)一(yi)塊(kuai)“電(dian)磁鐵(tie)”。這(zhe)種電(dian)磁鐵(tie)上(shang)的磁能要比永磁能大放(fang)多倍，它能吸起(qi)比它重20倍的鐵(tie)塊(kuai)，而當(dang)(dang)電(dian)源切斷后(hou)，U型鐵(tie)棒(bang)(bang)就什么鐵(tie)塊(kuai)也吸不住，重新成為一(yi)根普通的鐵(tie)棒(bang)(bang)。

斯特(te)金(jin)的電磁鐵發(fa)明，使人們看到了把(ba)電能轉(zhuan)化為磁能的光明前(qian)景，這(zhe)一發(fa)明很快在英國(guo)、美國(guo)以(yi)及西歐(ou)一些(xie)沿(yan)海國(guo)家傳播開來(lai)。

1829年，美國電學(xue)家(jia)亨利(li)對斯特(te)金電磁鐵(tie)裝(zhuang)置進行(xing)了一(yi)些革新(xin)(xin)，絕緣導線(xian)代替裸銅(tong)導線(xian)，因(yin)此(ci)不(bu)必擔心被銅(tong)導線(xian)過分靠近而短路。由于(yu)導線(xian)有了絕緣層，就(jiu)可以將它(ta)們一(yi)圈圈地緊(jin)緊(jin)地繞在(zai)一(yi)起，由于(yu)線(xian)圈越密集，產生的(de)磁場就(jiu)越強，這樣就(jiu)大大提高了把電能(neng)轉化為磁能(neng)的(de)能(neng)力。到了1831年，亨利(li)試制(zhi)出了一(yi)塊更新(xin)(xin)的(de)電磁鐵(tie)，雖然它(ta)的(de)體積并不(bu)大，但它(ta)能(neng)吸起1噸重(zhong)的(de)鐵(tie)塊。

電(dian)(dian)磁(ci)(ci)(ci)鐵(tie)(tie)(tie)內部(bu)帶(dai)有鐵(tie)(tie)(tie)心的(de)(de)、利用通(tong)(tong)有電(dian)(dian)流的(de)(de)線(xian)圈(quan)使其像(xiang)磁(ci)(ci)(ci)鐵(tie)(tie)(tie)一(yi)樣(yang)具有磁(ci)(ci)(ci)性(xing)的(de)(de)裝置叫做電(dian)(dian)磁(ci)(ci)(ci)鐵(tie)(tie)(tie)，通(tong)(tong)常制(zhi)(zhi)成(cheng)條形(xing)或(huo)蹄形(xing)。鐵(tie)(tie)(tie)心要(yao)用容易磁(ci)(ci)(ci)化(hua)，又(you)容易消(xiao)失(shi)磁(ci)(ci)(ci)性(xing)的(de)(de)軟鐵(tie)(tie)(tie)或(huo)硅(gui)鋼來制(zhi)(zhi)做。這(zhe)樣(yang)的(de)(de)電(dian)(dian)磁(ci)(ci)(ci)鐵(tie)(tie)(tie)在通(tong)(tong)電(dian)(dian)時(shi)有磁(ci)(ci)(ci)性(xing)，斷電(dian)(dian)后就隨之(zhi)消(xiao)失(shi)。 電(dian)(dian)磁(ci)(ci)(ci)鐵(tie)(tie)(tie)有許(xu)多(duo)優點：電(dian)(dian)磁(ci)(ci)(ci)鐵(tie)(tie)(tie)磁(ci)(ci)(ci)性(xing)的(de)(de)有無，可以(yi)用通(tong)(tong)、斷電(dian)(dian)流控制(zhi)(zhi)。磁(ci)(ci)(ci)性(xing)的(de)(de)大(da)小可以(yi)用電(dian)(dian)流的(de)(de)強弱或(huo)線(xian)圈(quan)的(de)(de)匝數來控制(zhi)(zhi)。

電磁鐵的主要特點

1、采用全(quan)密封結構，防潮性能(neng)好。

2、經計算機優化設計，結構(gou)合理、自重輕、吸(xi)力大、能耗低。

3、勵磁線(xian)圈(quan)經特別工(gong)藝處理，提高了(le)線(xian)圈(quan)的電(dian)器和(he)機械性能，絕(jue)緣資料熱等級(ji)到(dao)達C級(ji)，運用壽命長。

4、普通型電(dian)(dian)(dian)磁鐵的額定(ding)通電(dian)(dian)(dian)持續率由(you)曩昔的50%提高(gao)到60%，提高(gao)了電(dian)(dian)(dian)磁鐵的運用功率。

5、超高溫型電磁鐵采(cai)用獨特隔熱方式，其間(jian)被吸物溫度有曩昔的(de)(de)600℃提高700℃，擴大了電磁鐵的(de)(de)適用范圍。

6、裝置(zhi)、運轉、保護簡潔。

電磁鐵工作原理

將(jiang)電(dian)(dian)磁(ci)(ci)(ci)能變換為機械能以(yi)實(shi)現吸(xi)合(he)作(zuo)(zuo)功的(de)一種電(dian)(dian)器。通常由軟磁(ci)(ci)(ci)材料制(zhi)成的(de)鐵(tie)(tie)心(xin)、銜(xian)鐵(tie)(tie)和勵(li)磁(ci)(ci)(ci)繞組(zu)組(zu)成。當勵(li)磁(ci)(ci)(ci)繞組(zu)通電(dian)(dian)時，繞組(zu)周圍產生磁(ci)(ci)(ci)場，鐵(tie)(tie)心(xin)磁(ci)(ci)(ci)化(hua)，并產生電(dian)(dian)磁(ci)(ci)(ci)吸(xi)力吸(xi)引銜(xian)鐵(tie)(tie)，使(shi)之運動(dong)作(zuo)(zuo)功。電(dian)(dian)磁(ci)(ci)(ci)鐵(tie)(tie)主要用(yong)于操動(dong)、牽引機械裝(zhuang)置，以(yi)達到預期的(de)目的(de)。工業上(shang)(shang)常用(yong)的(de)電(dian)(dian)磁(ci)(ci)(ci)鐵(tie)(tie)有制(zhi)動(dong)電(dian)(dian)磁(ci)(ci)(ci)鐵(tie)(tie)、牽引電(dian)(dian)磁(ci)(ci)(ci)鐵(tie)(tie)、起重電(dian)(dian)磁(ci)(ci)(ci)鐵(tie)(tie)和閥(fa)用(yong)電(dian)(dian)磁(ci)(ci)(ci)鐵(tie)(tie)等。此外，屬(shu)于電(dian)(dian)磁(ci)(ci)(ci)鐵(tie)(tie)類的(de)還有用(yong)以(yi)傳遞或(huo)隔斷(duan)兩(liang)軸(zhou)間的(de)機械聯(lian)系(xi)的(de)電(dian)(dian)磁(ci)(ci)(ci)聯(lian)軸(zhou)器;用(yong)在機床工作(zuo)(zuo)臺上(shang)(shang)以(yi)吸(xi)牢(lao)磁(ci)(ci)(ci)性材料工件的(de)電(dian)(dian)磁(ci)(ci)(ci)吸(xi)盤;供(gong)高能物(wu)理(li)、核聚變研究、磁(ci)(ci)(ci)流體發電(dian)(dian)和高速(su)懸浮列車等方面使(shi)用(yong)的(de)、能產生高達數十特（斯(si)拉）的(de)磁(ci)(ci)(ci)通密(mi)度而幾乎(hu)不消耗繞組(zu)功率的(de)超導電(dian)(dian)磁(ci)(ci)(ci)鐵(tie)(tie)等。

起重電磁鐵

用(yong)來吊運(yun)和裝卸(xie)鐵(tie)(tie)磁(ci)性物體(ti)的(de)電(dian)(dian)磁(ci)鐵(tie)(tie)。工(gong)業上常(chang)(chang)用(yong)以吊運(yun)或(huo)(huo)裝卸(xie)鐵(tie)(tie)礦石、鐵(tie)(tie)砂、廢鋼(gang)鐵(tie)(tie)、鋼(gang)錠、鋼(gang)軌以及各(ge)種鋼(gang)材和鋼(gang)質工(gong)件。起重電(dian)(dian)磁(ci)鐵(tie)(tie)通常(chang)(chang)做(zuo)成(cheng)圓(yuan)盤形或(huo)(huo)矩形，并帶有內磁(ci)極和外(wai)磁(ci)極。當(dang)勵(li)(li)磁(ci)繞組通電(dian)(dian)后，內外(wai)磁(ci)極均(jun)被磁(ci)化，吸引鋼(gang)質材料或(huo)(huo)工(gong)件（相當(dang)于一般電(dian)(dian)磁(ci)鐵(tie)(tie)中的(de)銜鐵(tie)(tie)），形成(cheng)一個閉合的(de)磁(ci)路。為保護勵(li)(li)磁(ci)繞組，使之(zhi)不(bu)因磁(ci)極與被吸引物體(ti)間的(de)機械撞擊所損(sun)傷，起重電(dian)(dian)磁(ci)鐵(tie)(tie)通常(chang)(chang)采用(yong)甲殼式結構(gou)，并且采用(yong)直流勵(li)(li)磁(ci)。

牽引電磁鐵

供牽(qian)引(yin)(yin)和推(tui)斥機械(xie)(xie)裝置(zhi)(zhi)用的(de)一(yi)種(zhong)電(dian)磁(ci)(ci)(ci)(ci)(ci)鐵(tie)(tie)。主要(yao)用于各種(zhong)自動設(she)備(bei)中，以實現遠距離控(kong)制。為(wei)了能(neng)夠在(zai)(zai)長行程(cheng)下獲(huo)得(de)較大的(de)電(dian)磁(ci)(ci)(ci)(ci)(ci)吸(xi)力(li)，牽(qian)引(yin)(yin)電(dian)磁(ci)(ci)(ci)(ci)(ci)鐵(tie)(tie)一(yi)般采用吸(xi)引(yin)(yin)特(te)性比較平坦的(de)甲殼式(shi)結構。其內(nei)部(bu)裝有(you)鐵(tie)(tie)心(xin)、銜鐵(tie)(tie)和勵磁(ci)(ci)(ci)(ci)(ci)線圈。使用時，將(jiang)鐵(tie)(tie)心(xin)固(gu)定(ding)在(zai)(zai)機械(xie)(xie)裝置(zhi)(zhi)的(de)靜止部(bu)件上(shang)，銜鐵(tie)(tie)則連接在(zai)(zai)牽(qian)引(yin)(yin)桿(gan)上(shang)。當勵磁(ci)(ci)(ci)(ci)(ci)繞(rao)組(zu)通電(dian)后，鐵(tie)(tie)心(xin)被磁(ci)(ci)(ci)(ci)(ci)化，產生電(dian)磁(ci)(ci)(ci)(ci)(ci)吸(xi)力(li)吸(xi)引(yin)(yin)銜鐵(tie)(tie)，后者則通過牽(qian)引(yin)(yin)桿(gan)來(lai)操縱所控(kong)制的(de)機械(xie)(xie)裝置(zhi)(zhi)的(de)機構。為(wei)了適(shi)應(ying)不同控(kong)制對象的(de)需要(yao)，牽(qian)引(yin)(yin)電(dian)磁(ci)(ci)(ci)(ci)(ci)鐵(tie)(tie)有(you)拉(la)動式(shi)和推(tui)動式(shi)兩種(zhong)，但(dan)都不具備(bei)復位(wei)裝置(zhi)(zhi)。牽(qian)引(yin)(yin)電(dian)磁(ci)(ci)(ci)(ci)(ci)鐵(tie)(tie)的(de)主要(yao)技術指標為(wei)一(yi)定(ding)行程(cheng)下的(de)電(dian)磁(ci)(ci)(ci)(ci)(ci)吸(xi)力(li)、操作頻(pin)率和壽(shou)命。

制動電磁鐵

作(zuo)(zuo)機(ji)械(xie)制(zhi)動(dong)(dong)(dong)用(yong)的(de)一(yi)種(zhong)電(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)鐵(tie)(tie)(tie)(tie)。主(zhu)(zhu)要(yao)用(yong)于(yu)電(dian)(dian)(dian)(dian)(dian)(dian)力(li)驅動(dong)(dong)(dong)裝置和(he)(he)起重(zhong)運輸設備中，并與(yu)制(zhi)動(dong)(dong)(dong)器(qi)配合(he)(he)使用(yong)，使電(dian)(dian)(dian)(dian)(dian)(dian)動(dong)(dong)(dong)機(ji)準確停車和(he)(he)懸吊著的(de)重(zhong)物不致墜落。制(zhi)動(dong)(dong)(dong)電(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)鐵(tie)(tie)(tie)(tie)按銜鐵(tie)(tie)(tie)(tie)行(xing)程(cheng)(cheng)(cheng)分(fen)(fen)為(wei)長行(xing)程(cheng)(cheng)(cheng)和(he)(he)短(duan)行(xing)程(cheng)(cheng)(cheng)兩類(lei)(lei);按勵磁(ci)(ci)方式分(fen)(fen)為(wei)直流和(he)(he)交流、并勵和(he)(he)串勵以及(ji)單相(xiang)和(he)(he)三(san)相(xiang)等(deng)種(zhong)類(lei)(lei)。制(zhi)動(dong)(dong)(dong)電(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)鐵(tie)(tie)(tie)(tie)的(de)工作(zuo)(zuo)原理是(shi)(shi)：當電(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)鐵(tie)(tie)(tie)(tie)的(de)繞組(zu)通(tong)(tong)電(dian)(dian)(dian)(dian)(dian)(dian)后(hou)，銜鐵(tie)(tie)(tie)(tie)被吸向鐵(tie)(tie)(tie)(tie)心，并通(tong)(tong)過(guo)制(zhi)動(dong)(dong)(dong)器(qi)中的(de)停檔壓(ya)迫制(zhi)動(dong)(dong)(dong)桿，使之(zhi)(zhi)移動(dong)(dong)(dong)，從(cong)而(er)迫使制(zhi)動(dong)(dong)(dong)器(qi)松閘。切斷線圈(quan)電(dian)(dian)(dian)(dian)(dian)(dian)源后(hou)，制(zhi)動(dong)(dong)(dong)桿在彈簧作(zuo)(zuo)用(yong)下(xia)使銜鐵(tie)(tie)(tie)(tie)脫(tuo)離(li)磁(ci)(ci)軛(e)，而(er)制(zhi)動(dong)(dong)(dong)器(qi)則將(jiang)機(ji)構剎住。制(zhi)動(dong)(dong)(dong)電(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)鐵(tie)(tie)(tie)(tie)的(de)主(zhu)(zhu)要(yao)技術(shu)參(can)數是(shi)(shi)行(xing)程(cheng)(cheng)(cheng)、一(yi)定(ding)行(xing)程(cheng)(cheng)(cheng)下(xia)的(de)電(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)吸力(li)、操(cao)作(zuo)(zuo)頻率(lv)和(he)(he)通(tong)(tong)電(dian)(dian)(dian)(dian)(dian)(dian)持續(xu)率(lv)。操(cao)作(zuo)(zuo)頻率(lv)是(shi)(shi)指(zhi)每小時(shi)(shi)操(cao)作(zuo)(zuo)的(de)次(ci)數;通(tong)(tong)電(dian)(dian)(dian)(dian)(dian)(dian)持續(xu)率(lv)是(shi)(shi)指(zhi)每次(ci)通(tong)(tong)電(dian)(dian)(dian)(dian)(dian)(dian)時(shi)(shi)間與(yu)每次(ci)通(tong)(tong)電(dian)(dian)(dian)(dian)(dian)(dian)及(ji)不通(tong)(tong)電(dian)(dian)(dian)(dian)(dian)(dian)時(shi)(shi)間之(zhi)(zhi)和(he)(he)的(de)百分(fen)(fen)比。使用(yong)中，制(zhi)動(dong)(dong)(dong)電(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)鐵(tie)(tie)(tie)(tie)與(yu)瓦(wa)式制(zhi)動(dong)(dong)(dong)器(qi)相(xiang)配合(he)(he)時(shi)(shi)用(yong)短(duan)行(xing)程(cheng)(cheng)(cheng)類(lei)(lei);與(yu)皮帶制(zhi)動(dong)(dong)(dong)器(qi)相(xiang)配合(he)(he)時(shi)(shi)用(yong)長行(xing)程(cheng)(cheng)(cheng)類(lei)(lei)。制(zhi)動(dong)(dong)(dong)電(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)鐵(tie)(tie)(tie)(tie)通(tong)(tong)過(guo)液壓(ya)方式將(jiang)電(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)力(li)傳遞給制(zhi)動(dong)(dong)(dong)機(ji)構的(de)稱液壓(ya)制(zhi)動(dong)(dong)(dong)電(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)鐵(tie)(tie)(tie)(tie)。

閥用電磁鐵

供遠距離操(cao)作各種(zhong)液(ye)壓、氣(qi)動(dong)系統閥(fa)(fa)門(men)的(de)電(dian)磁(ci)(ci)鐵(tie)(tie)(tie)。常(chang)用于(yu)各種(zhong)金(jin)屬切削機(ji)床中(zhong)。閥(fa)(fa)用電(dian)磁(ci)(ci)鐵(tie)(tie)(tie)不設復(fu)位(wei)裝置，而由閥(fa)(fa)體中(zhong)的(de)彈(dan)簧(huang)使之復(fu)位(wei)。當電(dian)磁(ci)(ci)鐵(tie)(tie)(tie)的(de)勵磁(ci)(ci)繞組(zu)通過電(dian)流(liu)時，電(dian)磁(ci)(ci)吸(xi)力(li)即克服彈(dan)簧(huang)阻力(li)，使閥(fa)(fa)體的(de)推(tui)(tui)桿(gan)移動(dong)，將閥(fa)(fa)門(men)開啟;當勵磁(ci)(ci)繞組(zu)斷電(dian)后，在復(fu)位(wei)彈(dan)簧(huang)作用下，閥(fa)(fa)體推(tui)(tui)桿(gan)便推(tui)(tui)動(dong)銜鐵(tie)(tie)(tie)，使其移動(dong)額(e)定行程(cheng)處，閥(fa)(fa)門(men)關閉(bi)。閥(fa)(fa)用電(dian)磁(ci)(ci)鐵(tie)(tie)(tie)分為濕式(shi)和干式(shi)兩(liang)種(zhong)。濕式(shi)閥(fa)(fa)用電(dian)磁(ci)(ci)鐵(tie)(tie)(tie)的(de)銜鐵(tie)(tie)(tie)在液(ye)壓油中(zhong)工作，由于(yu)油的(de)冷(leng)卻作用，使其與(yu)具有相同(tong)吸(xi)力(li)的(de)電(dian)磁(ci)(ci)鐵(tie)(tie)(tie)相比，有較小的(de)尺寸。

電磁鐵的應用

門(men)禁：為什么(me)門(men)禁可以在(zai)沒刷卡(ka)時把門(men)牢牢的“抓住”？原來(lai)單元門(men)是由鋼材(cai)料做(zuo)成的，那個金(jin)屬體(ti)(ti)在(zai)通電時可以產生強大(da)的磁(ci)場，產生的磁(ci)力能把門(men)牢牢的吸住，而刷卡(ka)的瞬間，切(qie)斷電流，金(jin)屬體(ti)(ti)失去磁(ci)性，我們就(jiu)可以打開門(men)了。那個金(jin)屬體(ti)(ti)其(qi)實是一塊(kuai)電磁(ci)鐵。

電(dian)磁(ci)(ci)起(qi)重(zhong)機(ji)：最直接(jie)的應用之一是電(dian)磁(ci)(ci)起(qi)重(zhong)機(ji)。電(dian)磁(ci)(ci)鐵(tie)安裝在吊(diao)車上，通電(dian)后吸起(qi)大(da)量(liang)鋼鐵(tie)，移動到另一個位(wei)置(zhi)后切斷電(dian)流，鋼鐵(tie)被放下(xia)，免去了打捆的麻煩。大(da)型電(dian)磁(ci)(ci)起(qi)重(zhong)機(ji)一次可以吊(diao)起(qi)幾噸(dun)鋼材(cai)。

在電(dian)動機、發電(dian)機、電(dian)鈴(ling)和電(dian)磁(ci)繼電(dian)器(qi)里也(ye)用到電(dian)磁(ci)鐵(tie)。全自動洗衣機的(de)進水、排水閥門(men)，衛生間里感應式沖水器(qi)的(de)閥門(men)，也(ye)都(dou)是(shi)由電(dian)磁(ci)鐵(tie)控制的(de)。

電磁(ci)鐵的另一(yi)個應用是產生強(qiang)磁(ci)場。現代技術(shu)中很多(duo)地(di)方需要(yao)的強(qiang)磁(ci)場都由電磁(ci)鐵提供，如大型電動機、發電機、磁(ci)療設備等。