青浦電機的(de)(de)原理(li):電(dian)(dian)(dian)機的(de)(de)原理(li)很簡(jian)單(dan),簡(jian)單(dan)的(de)(de)說就(jiu)是(shi)利用電(dian)(dian)(dian)能(neng)在(zai)線圈上產生旋轉(zhuan)(zhuan)磁(ci)場,并(bing)推動(dong)(dong)(dong)轉(zhuan)(zhuan)子轉(zhuan)(zhuan)動(dong)(dong)(dong)的(de)(de)裝置。學過(guo)電(dian)(dian)(dian)磁(ci)感應定(ding)(ding)律的(de)(de)都(dou)知道(dao),通電(dian)(dian)(dian)的(de)(de)線圈在(zai)磁(ci)場中會受力轉(zhuan)(zhuan)動(dong)(dong)(dong),電(dian)(dian)(dian)機的(de)(de)基本原理(li)就(jiu)是(shi)如此,這是(shi)初(chu)中物(wu)理(li)的(de)(de)知識(shi)。電(dian)(dian)(dian)機結構:拆開過(guo)電(dian)(dian)(dian)機的(de)(de)人都(dou)知道(dao),電(dian)(dian)(dian)機主要是(shi)兩部(bu)分組成,固定(ding)(ding)不動(dong)(dong)(dong)的(de)(de)定(ding)(ding)子部(bu)分以及轉(zhuan)(zhuan)動(dong)(dong)(dong)的(de)(de)轉(zhuan)(zhuan)子部(bu)分,具體(ti)如下:
1、定子(zi)(靜(jing)止部分)
定(ding)子(zi)鐵心(xin):電機磁路重要部(bu)分,并在其上(shang)放置定(ding)子(zi)繞組;
定子(zi)繞(rao)組:就是線圈,電動機的電路部分,接電源,用于產生旋轉磁場;
機(ji)座:固定(ding)定(ding)子鐵心及(ji)電機(ji)端蓋(gai),并起(qi)防(fang)護、散熱等作用;
2、轉子(旋轉部分(fen))
轉子鐵(tie)心(xin):電機磁路(lu)的重(zhong)要部分,在鐵(tie)心(xin)槽(cao)內(nei)放置轉子繞組;
轉(zhuan)子繞組:切割定子旋轉(zhuan)磁(ci)場產生感應電(dian)(dian)動勢及電(dian)(dian)流,并形成(cheng)電(dian)(dian)磁(ci)轉(zhuan)矩從而使(shi)電(dian)(dian)動機旋轉(zhuan);
電(dian)機的(de)幾個計(ji)算(suan)公(gong)式:
1、電磁相關的
1)電(dian)動機的(de)感應電(dian)動勢公式(shi):E=4.44*f*N*Φ,E為(wei)線(xian)圈(quan)電(dian)動勢、 f為(wei)頻率 、 S為(wei)環繞出的(de)導(dao)體(比(bi)如(ru)鐵(tie)芯)橫截面積、 N為(wei)匝數(shu)、Φ是(shi)磁通。
公(gong)式是怎(zen)么推(tui)導來(lai)的(de)(de),這些事情我(wo)們就不去鉆研(yan)了,我(wo)們主要是看看怎(zen)么利(li)用它。感(gan)應(ying)(ying)電(dian)動(dong)勢是電(dian)磁感(gan)應(ying)(ying)的(de)(de)本質,有感(gan)應(ying)(ying)電(dian)動(dong)勢的(de)(de)導體(ti)閉合后,就會產生感(gan)應(ying)(ying)電(dian)流(liu)。感(gan)應(ying)(ying)電(dian)流(liu)在磁場中就會受到安(an)培力,產生磁矩,從(cong)而推(tui)動(dong)線圈轉動(dong)。
從上面(mian)公式知道,電動勢大小與電源(yuan)頻率、線圈匝數(shu)及(ji)磁通量成正比(bi)。
磁(ci)通(tong)量計算公(gong)式(shi)Φ=B*S*COSθ,當面積為S的平面與(yu)磁(ci)場(chang)方(fang)向垂(chui)直的時候,角θ為0,COSθ就等于1,公(gong)式(shi)就變成Φ=B*S。
將上面兩個(ge)公(gong)式結合一下,就可以得(de)到電(dian)機磁通強度計算公(gong)式為:B=E/(4.44*f*N*S)。
2)另外一個(ge)是(shi)安培力(li)公(gong)式,我們要知道線圈(quan)受到的(de)力(li)是(shi)多少,就(jiu)需要這個(ge)公(gong)式F=I*L*B*sinα,其(qi)中I為電流強度(du),L為導體長度(du),B為磁(ci)(ci)場(chang)強度(du),α是(shi)電流方(fang)(fang)向與(yu)磁(ci)(ci)場(chang)方(fang)(fang)向間的(de)夾角。當導線垂直于磁(ci)(ci)場(chang)時(shi)候(hou),公(gong)式就(jiu)變成F=I*L*B了(如果是(shi)N匝線圈(quan)的(de)話,磁(ci)(ci)通B就(jiu)是(shi)N匝線圈(quan)的(de)總磁(ci)(ci)通,而(er)不需要再乘N了)。
知道了受力,就知道轉矩(ju),轉矩(ju)等(deng)于扭(niu)力乘(cheng)以作用(yong)半徑,T=r*F=r*I*B*L(向量乘(cheng)積)。通(tong)過(guo)功(gong)率(lv)(lv)=力*速度(du)(P=F*V)以及線速度(du)V=2πR*每秒(miao)轉速(n秒(miao))兩個公式 ,可以與功(gong)率(lv)(lv)建立上(shang)關系,得(de)到(dao)下面序號(hao)3的公式。不過(guo)要注意,這時(shi)候使用(yong)實(shi)際輸出(chu)(chu)扭(niu)矩(ju),所以計算出(chu)(chu)的功(gong)率(lv)(lv)是(shi)輸出(chu)(chu)功(gong)率(lv)(lv)。
2、交(jiao)流異(yi)步電(dian)機(ji)(ji)的轉(zhuan)(zhuan)速計算公式(shi):n=60f/P,這個(ge)很(hen)簡單(dan),轉(zhuan)(zhuan)速與(yu)電(dian)源(yuan)頻率成正比(bi),與(yu)電(dian)機(ji)(ji)極(ji)對子(記住是一對)數(shu)成反比(bi),直接套用公式(shi)就好。不過這個(ge)公式(shi)實際計算出是同(tong)步轉(zhuan)(zhuan)速(旋轉(zhuan)(zhuan)磁場速度),異(yi)步電(dian)機(ji)(ji)實際轉(zhuan)(zhuan)速會(hui)略低于同(tong)步轉(zhuan)(zhuan)速,所以我們往往會(hui)看到(dao)4極(ji)電(dian)機(ji)(ji)一般是1400多轉(zhuan)(zhuan),達不到(dao)1500轉(zhuan)(zhuan)。
3、電(dian)機(ji)轉矩、功(gong)(gong)(gong)率(lv)(lv)(lv)計轉速(su)的關系(xi):T=9550P/n(P是電(dian)機(ji)功(gong)(gong)(gong)率(lv)(lv)(lv)、n是電(dian)機(ji)轉速(su)),可以從上(shang)面序號(hao)1內(nei)容(rong)中(zhong)推導出(chu)來,不過我們沒必(bi)要學(xue)會(hui)推導,記住這(zhe)個(ge)計算公(gong)式(shi)就(jiu)可以。不過再次提醒,公(gong)式(shi)中(zhong)功(gong)(gong)(gong)率(lv)(lv)(lv)P不是輸(shu)(shu)(shu)入(ru)功(gong)(gong)(gong)率(lv)(lv)(lv),而是輸(shu)(shu)(shu)出(chu)功(gong)(gong)(gong)率(lv)(lv)(lv),由于電(dian)機(ji)有損耗,輸(shu)(shu)(shu)入(ru)功(gong)(gong)(gong)率(lv)(lv)(lv)不等于輸(shu)(shu)(shu)出(chu)功(gong)(gong)(gong)率(lv)(lv)(lv)。但是書(shu)本上(shang)往往理(li)想(xiang)化,將輸(shu)(shu)(shu)入(ru)功(gong)(gong)(gong)率(lv)(lv)(lv)等于輸(shu)(shu)(shu)出(chu)功(gong)(gong)(gong)率(lv)(lv)(lv)了(le)。
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