挖掘機在工作發展過程中出現發動機進行自動熄火；再次啟動時，起動機運轉可以正常，但發動機技術卻不能通過啟動，并伴隨有少量的黑煙從排氣管冒出。維修挖掘機第一臺液壓挖掘機由法國波克蘭工廠發明成功。由于液壓技術的應用，20世紀40年代有了在拖拉機上配裝液壓反鏟地懸掛式挖掘機。挖掘機維修最重要的三個參數：操作重量（質量），發動機功率和鏟斗斗容。修理挖掘機常(chang)見的(de)挖(wa)掘(jue)機(ji)結構(gou)包括，動力裝置，工(gong)作裝置，回轉(zhuan)機(ji)構(gou)，操縱(zong)機(ji)構(gou)，傳動機(ji)構(gou)，行(xing)走機(ji)構(gou)和輔助設施等。

根(gen)據飛機(ji)(ji)(ji)維(wei)修手冊的(de)(de)(de)(de)(de)(de)相關故障診斷(duan)和過(guo)去的(de)(de)(de)(de)(de)(de)經驗修復(fu)，首先(xian)維(wei)修人(ren)員(yuan)保險絲飛機(ji)(ji)(ji)的(de)(de)(de)(de)(de)(de)保險絲盒，發(fa)動(dong)(dong)(dong)(dong)機(ji)(ji)(ji)油(you)門步進(jin)電(dian)機(ji)(ji)(ji)的(de)(de)(de)(de)(de)(de)運行(xing)系(xi)統(tong)(tong)，電(dian)機(ji)(ji)(ji)系(xi)統(tong)(tong)和發(fa)動(dong)(dong)(dong)(dong)機(ji)(ji)(ji)燃料供給系(xi)統(tong)(tong)的(de)(de)(de)(de)(de)(de)發(fa)動(dong)(dong)(dong)(dong)機(ji)(ji)(ji)停止運轉，以(yi)及其他(ta)相關因(yin)素(su)和情況進(jin)行(xing)全面檢查的(de)(de)(de)(de)(de)(de)霧(wu)化噴頭，均(jun)未發(fa)現異常。進(jin)一步的(de)(de)(de)(de)(de)(de)分析(xi)，并(bing)且發(fa)動(dong)(dong)(dong)(dong)機(ji)(ji)(ji)不能與發(fa)動(dong)(dong)(dong)(dong)機(ji)(ji)(ji)負載相關的(de)(de)(de)(de)(de)(de)啟動(dong)(dong)(dong)(dong)過(guo)程中(zhong)被啟動(dong)(dong)(dong)(dong)的(de)(de)(de)(de)(de)(de)，因(yin)此，在控制(zhi)電(dian)路中(zhong)的(de)(de)(de)(de)(de)(de)故障在主(zhu)機(ji)(ji)(ji)上的(de)(de)(de)(de)(de)(de)最(zui)有可能的(de)(de)(de)(de)(de)(de)原因(yin)，在圖(tu)(tu)中(zhong)所示的(de)(de)(de)(de)(de)(de)機(ji)(ji)(ji)器的(de)(de)(de)(de)(de)(de)主(zhu)機(ji)(ji)(ji)控制(zhi)電(dian)路圖(tu)(tu)。

經檢(jian)查(cha)，發動(dong)(dong)機系統(tong)啟(qi)動(dong)(dong)時，繼電(dian)器A、B、C均能夠(gou)正常吸(xi)合(he)，從而(er)排除了因繼電(dian)器未吸(xi)合(he)而(er)導致(zhi)汽車發動(dong)(dong)機工作不(bu)能及時啟(qi)動(dong)(dong)的(de)可(ke)能性；隨后用萬用表(biao)可(ke)以測量控(kong)制電(dian)磁閥a和b的(de)電(dian)信號數據輸(shu)入端，結果分析發現(xian)問題(ti)均無電(dian)流(liu)主要通(tong)過，而(er)此(ci)時我們電(dian)路(lu)(lu)4是在閉(bi)俁狀(zhuang)態，若無電(dian)流(liu)以及通(tong)過，這只(zhi)能說(shuo)明液(ye)壓泵和閥控(kong)制器的(de)電(dian)源未接(jie)通(tong)。進一步提高檢(jian)查(cha)后發現(xian)，由于我國發電(dian)機向蓄電(dian)池供電(dian)的(de)線路(lu)(lu)其絕緣材料性能產生不(bu)好，致(zhi)使安裝在蓄電(dian)池正上方的(de)50A的(de)可(ke)熔接(jie)頭D因短路(lu)(lu)而(er)熔斷(duan)。在檢(jian)修管理(li)人員將線路(lu)(lu)信息進行研究絕緣技(ji)術(shu)處理(li)并更換(huan)可(ke)熔接(jie)頭后，再次開(kai)始啟(qi)動(dong)(dong)中國發動(dong)(dong)機時，故障出(chu)現(xian)癥狀(zhuang)已消失(shi)。

當按(an)鍵開關處于啟(qi)動(dong)(dong)位(wei)置時(shi)，一方(fang)面(mian)通(tong)過(guo)(guo)電(dian)路(lu)1的(de)(de)供電(dian)電(dian)流使(shi)(shi)發(fa)(fa)動(dong)(dong)機(ji)節(jie)氣門步進馬達繼(ji)電(dian)器(qi)(qi) b 和(he)液壓(ya)(ya)系(xi)統泵(beng)(beng)控(kong)(kong)制(zhi)(zhi)繼(ji)電(dian)器(qi)(qi)吸(xi)氣、繼(ji)電(dian)器(qi)(qi)吸(xi)氣，液壓(ya)(ya)泵(beng)(beng)閥(fa)(fa)控(kong)(kong)制(zhi)(zhi)器(qi)(qi)(pvc)連(lian)接(jie)到液壓(ya)(ya)泵(beng)(beng)的(de)(de)電(dian)路(lu)5控(kong)(kong)制(zhi)(zhi)電(dian)磁(ci)閥(fa)(fa) a 和(he) b，另一方(fang)面(mian)通(tong)過(guo)(guo)電(dian)路(lu)2將電(dian)源供給(gei)啟(qi)動(dong)(dong)控(kong)(kong)制(zhi)(zhi)器(qi)(qi)(e，c) ，使(shi)(shi)其連(lian)接(jie)到蓄電(dian)池，電(dian)源電(dian)流使(shi)(shi)繼(ji)電(dian)器(qi)(qi) a 通(tong)過(guo)(guo)電(dian)路(lu)3吸(xi)入，從而使(shi)(shi)電(dian)源通(tong)過(guo)(guo)電(dian)路(lu)4向(xiang)液壓(ya)(ya)泵(beng)(beng)控(kong)(kong)制(zhi)(zhi)器(qi)(qi)供電(dian)。 當挖掘機(ji)發(fa)(fa)動(dong)(dong)機(ji)控(kong)(kong)制(zhi)(zhi)單元和(he)液壓(ya)(ya)泵(beng)(beng)閥(fa)(fa)控(kong)(kong)制(zhi)(zhi)器(qi)(qi)同(tong)時(shi)上(shang)電(dian)時(shi)，兩者(zhe)共同(tong)處理發(fa)(fa)動(dong)(dong)機(ji)、液壓(ya)(ya)泵(beng)(beng)和(he)主(zhu)(zhu)控(kong)(kong)閥(fa)(fa)中(zhong)多個(ge)傳(chuan)感器(qi)(qi)的(de)(de)信(xin)號，然后給(gei)液壓(ya)(ya)泵(beng)(beng)一個(ge)信(xin)號，控(kong)(kong)制(zhi)(zhi)電(dian)磁(ci)閥(fa)(fa) a 和(he) b，用來(lai)確(que)定內閥(fa)(fa)芯的(de)(de)排量。 這(zhe)樣，通(tong)過(guo)(guo)將導向(xiang)液壓(ya)(ya)泵(beng)(beng)的(de)(de)油流量調節(jie)到主(zhu)(zhu)液壓(ya)(ya)泵(beng)(beng)的(de)(de)伺服系(xi)統中(zhong)，從而改變(bian)主(zhu)(zhu)液壓(ya)(ya)泵(beng)(beng)斜盤的(de)(de)傾斜角度，調節(jie)主(zhu)(zhu)液壓(ya)(ya)泵(beng)(beng)的(de)(de)排量以匹配發(fa)(fa)動(dong)(dong)機(ji)的(de)(de)啟(qi)動(dong)(dong)。