一、汽車發電機不發電是怎么回事

汽(qi)車交流(liu)發電(dian)(dian)(dian)機(ji)(ji)(ji)正常(chang)發電(dian)(dian)(dian)，必(bi)須(xu)(xu)具備兩個條件(jian)： 一是(shi)(shi)勵磁(ci)電(dian)(dian)(dian)路(lu)、定子繞組電(dian)(dian)(dian)路(lu)和整流(liu)器必(bi)須(xu)(xu)工作正常(chang)； 二是(shi)(shi)交流(liu)發電(dian)(dian)(dian)機(ji)(ji)(ji)轉子必(bi)須(xu)(xu)旋(xuan)轉。汽(qi)車發電(dian)(dian)(dian)機(ji)(ji)(ji)不發電(dian)(dian)(dian)可能是(shi)(shi)某些零部件(jian)出現了(le)問題，以下(xia)是(shi)(shi)常(chang)見的(de)汽(qi)車發電(dian)(dian)(dian)機(ji)(ji)(ji)不發電(dian)(dian)(dian)的(de)原因：

1、二極管擊穿，不起整流作(zuo)用。

2、電(dian)刷(shua)在電(dian)刷(shua)架內卡住，發(fa)(fa)電(dian)機因不勵磁而不能發(fa)(fa)電(dian)。

3、轉(zhuan)子(zi)(zi)的(de)(de)磁場線(xian)(xian)圈(quan)(quan)不(bu)通電：轉(zhuan)子(zi)(zi)線(xian)(xian)圈(quan)(quan)的(de)(de)折疊層數(shu)多，部分線(xian)(xian)圈(quan)(quan)在(zai)浸絕(jue)緣漆時(shi)，沒有浸到線(xian)(xian)圈(quan)(quan)底(di)層中(zhong)去，底(di)層線(xian)(xian)圈(quan)(quan)匝與匝之間(jian)存在(zai)一定的(de)(de)間(jian)隙。隨著發動機(ji)轉(zhuan)速的(de)(de)變化，底(di)層線(xian)(xian)圈(quan)(quan)將(jiang)存在(zai)不(bu)同的(de)(de)離心力。線(xian)(xian)圈(quan)(quan)收縮、膨脹的(de)(de)頻(pin)率，決定了線(xian)(xian)圈(quan)(quan)和引(yin)線(xian)(xian)角度大小變換的(de)(de)次數(shu)，常見磁場線(xian)(xian)圈(quan)(quan)到滑(hua)環的(de)(de)引(yin)線(xian)(xian)，特別是(shi)底(di)層線(xian)(xian)圈(quan)(quan)的(de)(de)引(yin)線(xian)(xian)使用(yong)過(guo)久，將(jiang)產生金(jin)屬疲勞而折斷。

4、定(ding)子線圈相(xiang)間(jian)短路或搭鐵。

5、轉子的(de)爪極松(song)(song)動：若在軸上稍(shao)有松(song)(song)動，則爪極內端(duan)面(mian)與磁鐵端(duan)面(mian)之間就(jiu)會(hui)有間隙(xi)產(chan)生，磁場線圈產(chan)生的(de)磁通就(jiu)會(hui)在此(ci)漏掉(diao)，導(dao)致定(ding)子的(de)磁通大(da)大(da)減少，定(ding)子線圈感應(ying)的(de)電動勢也(ye)因此(ci)大(da)大(da)減小(xiao)，以(yi)致于不(bu)能產(chan)生足夠的(de)電壓對(dui)蓄電池進行充電。

該圖片由注冊用戶"健康生活"提供，版權聲明反饋

二、汽車電機不發電故障如何檢修

1、就車檢測法

汽車發(fa)(fa)電機(ji)故障(zhang)時，可(ke)以不拆(chai)卸發(fa)(fa)電機(ji)，在車上對其檢測，概略判斷是(shi)否有故障(zhang)。

（1）萬用表電壓檔檢測

將萬用(yong)表旋(xuan)鈕旋(xuan)至(zhi)直流電(dian)(dian)(dian)(dian)壓(ya)(ya)30V檔(dang)（或(huo)用(yong)一般的直流電(dian)(dian)(dian)(dian)壓(ya)(ya)表適(shi)當檔(dang)），把(ba)紅表筆接(jie)發電(dian)(dian)(dian)(dian)機“電(dian)(dian)(dian)(dian)樞(shu)”接(jie)柱，黑表筆接(jie)外殼，讓發動機運轉(zhuan)在中速以上，12V電(dian)(dian)(dian)(dian)氣(qi)系(xi)(xi)統的電(dian)(dian)(dian)(dian)壓(ya)(ya)標(biao)準值應在14V左右，24V電(dian)(dian)(dian)(dian)氣(qi)系(xi)(xi)統的電(dian)(dian)(dian)(dian)壓(ya)(ya)標(biao)準值應在28V左右。若測(ce)的電(dian)(dian)(dian)(dian)壓(ya)(ya)為蓄電(dian)(dian)(dian)(dian)池電(dian)(dian)(dian)(dian)壓(ya)(ya)，則表明(ming)發電(dian)(dian)(dian)(dian)機不發電(dian)(dian)(dian)(dian)。

（2）外接電流表檢測

當汽車儀(yi)表(biao)板上(shang)沒有電(dian)(dian)流(liu)(liu)(liu)表(biao)時，可用(yong)外接(jie)直流(liu)(liu)(liu)電(dian)(dian)流(liu)(liu)(liu)表(biao)來檢測。先把發(fa)(fa)電(dian)(dian)機(ji)“電(dian)(dian)樞”接(jie)柱導線拆下，再(zai)將量(liang)程為20A左(zuo)右(you)的(de)直流(liu)(liu)(liu)電(dian)(dian)流(liu)(liu)(liu)表(biao)正(zheng)(zheng)極(ji)接(jie)發(fa)(fa)電(dian)(dian)機(ji)“電(dian)(dian)樞”，負極(ji)導線接(jie)上(shang)述拆下接(jie)頭。當發(fa)(fa)動(dong)機(ji)在中速(su)以上(shang)運轉（不使用(yong)其他電(dian)(dian)器設備）時，電(dian)(dian)流(liu)(liu)(liu)表(biao)有3A~5A充電(dian)(dian)指示(shi)，表(biao)明發(fa)(fa)電(dian)(dian)機(ji)工(gong)作正(zheng)(zheng)常，否則發(fa)(fa)電(dian)(dian)機(ji)不發(fa)(fa)電(dian)(dian)。

（3）試燈（汽車燈泡）法

當沒有萬用表和直流電表時，可用汽車燈泡做一試燈來檢測。將燈泡兩端(duan)焊(han)接適(shi)當(dang)長度的導線(xian)，并(bing)在其(qi)兩端(duan)接上鍔(e)魚夾(jia)。檢測前先將發(fa)(fa)電機(ji)“電樞”接柱的導線(xian)拆下，再將試燈的一端(duan)夾(jia)住發(fa)(fa)電機(ji)“電樞”接柱，另一端(duan)搭鐵，當(dang)發(fa)(fa)動機(ji)中速(su)運轉時，試燈亮(liang)度說明發(fa)(fa)電機(ji)工作正常，否則發(fa)(fa)電機(ji)不(bu)發(fa)(fa)電。

（4）改變發動機轉速、觀察大燈亮度法

起動發(fa)動機(ji)(ji)(ji)后，打開大燈，讓發(fa)動機(ji)(ji)(ji)轉(zhuan)速(su)從怠(dai)速(su)逐漸提(ti)高(gao)(gao)到中等轉(zhuan)速(su)，大燈的(de)亮度若隨轉(zhuan)速(su)的(de)提(ti)高(gao)(gao)而增(zeng)加，說明發(fa)電機(ji)(ji)(ji)工作正常，否則為(wei)不發(fa)電。

（5）拆下蓄電池搭鐵看發動機（汽油機）是否工作法

當車上沒(mei)有微機(ji)控(kong)制電子裝置(zhi)時，可以用此(ci)種方法檢(jian)測。把發動機(ji)控(kong)制在中速(su)以上，拆下蓄(xu)電池搭(da)鐵線(xian)（一般是斷(duan)開蓄(xu)電池搭(da)鐵線(xian)上的控(kong)制總開關），若發動機(ji)工作(zuo)正(zheng)常(chang)，說明(ming)發電機(ji)發電，否則發電機(ji)有故障。

2、車下不解體檢測與判斷

維修汽車發(fa)電機故障(zhang)也可以(yi)選(xuan)擇從車上拆下發(fa)電機后，用下述方法檢查，進一步確(que)定故障(zhang)。

（1）用小燈泡（手電燈泡）判斷

把手(shou)電(dian)(dian)(dian)燈泡的(de)兩端接上導(dao)線做成(cheng)小(xiao)試燈，接于發(fa)(fa)(fa)電(dian)(dian)(dian)機“電(dian)(dian)(dian)樞”和外殼之間。用(yong)(yong)導(dao)線將蓄(xu)電(dian)(dian)(dian)池(chi)（或相同電(dian)(dian)(dian)壓的(de)干電(dian)(dian)(dian)池(chi)）正、負極分別連接在發(fa)(fa)(fa)電(dian)(dian)(dian)機的(de)兩磁場接柱“F1”、“F2”（內搭鐵的(de)交流發(fa)(fa)(fa)電(dian)(dian)(dian)機接“F”和“搭鐵”接柱）上，讓蓄(xu)電(dian)(dian)(dian)池(chi)給發(fa)(fa)(fa)電(dian)(dian)(dian)機激磁。用(yong)(yong)手(shou)快速轉動發(fa)(fa)(fa)動機皮帶盤，小(xiao)試燈說(shuo)明發(fa)(fa)(fa)電(dian)(dian)(dian)機工作正常，否則發(fa)(fa)(fa)電(dian)(dian)(dian)機不發(fa)(fa)(fa)電(dian)(dian)(dian)。

（2）萬用表電壓檔判斷

讓蓄電(dian)(dian)(dian)池給發(fa)(fa)電(dian)(dian)(dian)機激磁（接線方(fang)法同(tong)2．1），將萬用表(biao)(biao)選(xuan)擇在直流(liu)(liu)電(dian)(dian)(dian)壓(ya)3－5V（或一般直流(liu)(liu)電(dian)(dian)(dian)壓(ya)表(biao)(biao)適當檔(dang)）檔(dang)，黑、紅表(biao)(biao)筆分別(bie)接“搭鐵”和發(fa)(fa)電(dian)(dian)(dian)機“電(dian)(dian)(dian)樞”接柱，用手轉動(dong)皮(pi)帶盤，萬用表(biao)(biao)（或直流(liu)(liu)電(dian)(dian)(dian)壓(ya)表(biao)(biao)）指針(zhen)應有(you)擺動(dong)，否則(ze)發(fa)(fa)電(dian)(dian)(dian)機不發(fa)(fa)電(dian)(dian)(dian)。

（3）萬用表電阻檔檢測與判斷

用萬用表R×1電(dian)阻檔，測量各接線柱之間的(de)電(dian)阻（不(bu)同型號發電(dian)機(ji)的(de)電(dian)阻值(zhi)不(bu)同，下(xia)表為JF522A型發電(dian)機(ji)）值(zhi)，與正常值(zhi)比較，可以判(pan)斷出發電(dian)機(ji)是否(fou)有故障。

（4）示波器法檢測與判斷

將(jiang)發電(dian)機裝(zhuang)在電(dian)器試(shi)驗臺上，連(lian)接好示波器與發電(dian)機之間的導(dao)線，把發電(dian)機控(kong)制在中等(deng)轉速，發電(dian)機正常工(gong)作及各種故障所對應(ying)的電(dian)壓波形(xing)。