為了可靠準確地識(shi)別(bie)(bie)電(dian)纜，需要(yao)給被識(shi)別(bie)(bie)電(dian)纜加一特殊的信(xin)號，該信(xin)號要(yao)被接收機接收，利用這一特性便能識(shi)別(bie)(bie)出要(yao)找(zhao)的電(dian)纜。

電纜識別(bie)儀(yi)按(an)下述原(yuan)理工作：

發生器將周期(qi)性(xing)(xing)的(de)(de)(de)單極性(xing)(xing)電(dian)(dian)(dian)(dian)壓脈沖(chong)饋入要(yao)識別的(de)(de)(de)電(dian)(dian)(dian)(dian)纜(lan)(lan)(lan)中(zhong)，該(gai)(gai)電(dian)(dian)(dian)(dian)纜(lan)(lan)(lan)需要(yao)在遠端接地，以保證有(you)足夠大的(de)(de)(de)電(dian)(dian)(dian)(dian)流(liu)(liu)流(liu)(liu)過(guo)(guo)電(dian)(dian)(dian)(dian)纜(lan)(lan)(lan)。該(gai)(gai)系統要(yao)設計(ji)成返(fan)回電(dian)(dian)(dian)(dian)流(liu)(liu)不要(yao)從(cong)同一(yi)電(dian)(dian)(dian)(dian)纜(lan)(lan)(lan)中(zhong)返(fan)回，能做(zuo)到(dao)這(zhe)一(yi)點，饋入電(dian)(dian)(dian)(dian)纜(lan)(lan)(lan)中(zhong)的(de)(de)(de)脈沖(chong)電(dian)(dian)(dian)(dian)流(liu)(liu)的(de)(de)(de)方(fang)向(xiang)可做(zuo)為一(yi)明顯(xian)的(de)(de)(de)識別標準，流(liu)(liu)出去(qu)(qu)的(de)(de)(de)電(dian)(dian)(dian)(dian)流(liu)(liu)僅從(cong)這(zhe)一(yi)根電(dian)(dian)(dian)(dian)纜(lan)(lan)(lan)通(tong)過(guo)(guo)，所有(you)其(qi)它(ta)鄰(lin)近(jin)電(dian)(dian)(dian)(dian)纜(lan)(lan)(lan)中(zhong)流(liu)(liu)過(guo)(guo)的(de)(de)(de)都是返(fan)回電(dian)(dian)(dian)(dian)流(liu)(liu)，但它(ta)們的(de)(de)(de)極性(xing)(xing)相反。除(chu)了電(dian)(dian)(dian)(dian)流(liu)(liu)方(fang)向(xiang)這(zhe)一(yi)實際差異外，電(dian)(dian)(dian)(dian)流(liu)(liu)幅度也是一(yi)識別特征，流(liu)(liu)出去(qu)(qu)的(de)(de)(de)電(dian)(dian)(dian)(dian)流(liu)(liu)僅通(tong)過(guo)(guo)一(yi)根電(dian)(dian)(dian)(dian)纜(lan)(lan)(lan)、而返(fan)回電(dian)(dian)(dian)(dian)流(liu)(liu)可通(tong)過(guo)(guo)幾根電(dian)(dian)(dian)(dian)纜(lan)(lan)(lan)、這(zhe)意(yi)味著(zhu)流(liu)(liu)出去(qu)(qu)的(de)(de)(de)電(dian)(dian)(dian)(dian)流(liu)(liu)比流(liu)(liu)過(guo)(guo)其(qi)它(ta)電(dian)(dian)(dian)(dian)纜(lan)(lan)(lan)的(de)(de)(de)返(fan)回電(dian)(dian)(dian)(dian)流(liu)(liu)大。

接收(shou)(shou)機的(de)任務是(shi)探測(ce)流(liu)(liu)(liu)過電(dian)(dian)(dian)(dian)纜(lan)(lan)(lan)電(dian)(dian)(dian)(dian)流(liu)(liu)(liu)方(fang)(fang)向(xiang)(xiang)以(yi)及它(ta)的(de)大小。為(wei)達到這一(yi)(yi)目(mu)的(de)，電(dian)(dian)(dian)(dian)流(liu)(liu)(liu)卡(ka)鉗(qian)(qian)(qian)被用(yong)作傳感(gan)器(qi)，它(ta)帶有(you)一(yi)(yi)放大器(qi)并串聯在電(dian)(dian)(dian)(dian)路中(zhong)，卡(ka)鉗(qian)(qian)(qian)鉗(qian)(qian)(qian)住被測(ce)電(dian)(dian)(dian)(dian)纜(lan)(lan)(lan)，電(dian)(dian)(dian)(dian)流(liu)(liu)(liu)流(liu)(liu)(liu)過電(dian)(dian)(dian)(dian)纜(lan)(lan)(lan)產生的(de)磁場在卡(ka)鉗(qian)(qian)(qian)的(de)線圈中(zhong)感(gan)應出電(dian)(dian)(dian)(dian)壓(ya)，  該電(dian)(dian)(dian)(dian)壓(ya)極性由電(dian)(dian)(dian)(dian)流(liu)(liu)(liu)方(fang)(fang)向(xiang)(xiang)和卡(ka)鉗(qian)(qian)(qian)線圈的(de)方(fang)(fang)向(xiang)(xiang)決定。為(wei)了得到明(ming)顯有(you)電(dian)(dian)(dian)(dian)流(liu)(liu)(liu)方(fang)(fang)向(xiang)(xiang)的(de)電(dian)(dian)(dian)(dian)壓(ya)極性，對(dui)一(yi)(yi)束電(dian)(dian)(dian)(dian)纜(lan)(lan)(lan)中(zhong)所(suo)有(you)電(dian)(dian)(dian)(dian)纜(lan)(lan)(lan)進行測(ce)試(shi)都(dou)采取(qu)相同正(zheng)確的(de)繞組方(fang)(fang)向(xiang)(xiang)，這就是(shi)卡(ka)鉗(qian)(qian)(qian)上(shang)(shang)標(biao)有(you)箭頭的(de)原因。卡(ka)鉗(qian)(qian)(qian)上(shang)(shang)箭頭的(de)方(fang)(fang)向(xiang)(xiang)應指(zhi)向(xiang)(xiang)電(dian)(dian)(dian)(dian)纜(lan)(lan)(lan)遠端，卡(ka)鉗(qian)(qian)(qian)線圈中(zhong)感(gan)應的(de)電(dian)(dian)(dian)(dian)壓(ya)在表頭中(zhong)顯示出來，如果卡(ka)鉗(qian)(qian)(qian)按(an)上(shang)(shang)述方(fang)(fang)式連接，指(zhi)針(zhen)擺動方(fang)(fang)向(xiang)(xiang)可顯示電(dian)(dian)(dian)(dian)流(liu)(liu)(liu)方(fang)(fang)向(xiang)(xiang)，即只有(you)電(dian)(dian)(dian)(dian)流(liu)(liu)(liu)流(liu)(liu)(liu)出的(de)這根(gen)電(dian)(dian)(dian)(dian)纜(lan)(lan)(lan)指(zhi)針(zhen)向(xiang)(xiang)右偏，這根(gen)就是(shi)要找(zhao)的(de)電(dian)(dian)(dian)(dian)纜(lan)(lan)(lan)。所(suo)有(you)其它(ta)電(dian)(dian)(dian)(dian)纜(lan)(lan)(lan)只流(liu)(liu)(liu)過返回電(dian)(dian)(dian)(dian)流(liu)(liu)(liu)，指(zhi)針(zhen)向(xiang)(xiang)左偏、或無脈動電(dian)(dian)(dian)(dian)流(liu)(liu)(liu)，指(zhi)針(zhen)不偏轉。接收(shou)(shou)機上(shang)(shang)的(de)放大調(diao)(diao)節(jie)器(qi)可調(diao)(diao)整信號強度(du)。

識(shi)別(bie)儀主機各部分(fen)功能如(ru)下：

1.電(dian)源開關(guan)：控制整機電(dian)源通斷。

2.電(dian)(dian)源(yuan)輸(shu)入(ru)插座：用儀器(qi)所配電(dian)(dian)源(yuan)線，輸(shu)入(ru)50Hz、220V交流(liu)電(dian)(dian)源(yuan)。儀器(qi)使(shi)(shi)用時，應獨立使(shi)(shi)用三孔電(dian)(dian)源(yuan)插座，插座接地線就近直接接地。

3.保險座(zuo)：儀器使用(yong)10A保險芯，損壞(huai)時應換(huan)同規格保險芯。

4.黑接(jie)線柱(zhu)：測(ce)試時(shi)，用配套黑色測(ce)試線（Ф4插(cha)頭）插(cha)入此插(cha)孔，另一端測(ce)試夾接(jie)系(xi)統地。

5.紅接(jie)線(xian)柱(zhu)：測試(shi)時(shi)，用(yong)配(pei)套紅色測試(shi)線(xian)（Ф4插(cha)(cha)頭(tou)）插(cha)(cha)入此插(cha)(cha)孔，另一端測試(shi)夾接(jie)被測電纜芯線(xian)。

6.表頭：指(zhi)示輸出電流大小。

7.輸出調節：用(yong)于調整主機電(dian)(dian)流大小(xiao)，使用(yong)時根據測試電(dian)(dian)纜長短及接收器指示(shi)大小(xiao)適(shi)當調節。順(shun)時針(zhen)旋轉輸出電(dian)(dian)流增大。

接收(shou)機各部分功能(neng)如下：

1.幅度調節(jie)：順時(shi)針(zhen)旋(xuan)轉(zhuan)，接收機電表指示值增大，逆時(shi)針(zhen)旋(xuan)轉(zhuan)，指示值變小。

2.表頭：指示輸入信(xin)號幅度大小與極性。

工作方法：

電(dian)(dian)纜(lan)識別(bie)儀信號發生器由交(jiao)流電(dian)(dian)源(yuan)供電(dian)(dian)，它對已斷電(dian)(dian)的(de)(de)、要(yao)(yao)識別(bie)的(de)(de)電(dian)(dian)纜(lan)加(jia)上固定周期(qi)單極性(xing)的(de)(de)直流脈(mo)(mo)沖。發生器輸(shu)出(chu)線(xian)連(lian)在(zai)電(dian)(dian)纜(lan)芯線(xian)和接(jie)地(di)(di)(di)點或(huo)地(di)(di)(di)釘上，該電(dian)(dian)纜(lan)線(xian)鎧(kai)裝(zhuang)與大地(di)(di)(di)斷開，芯線(xian)在(zai)遠端與接(jie)地(di)(di)(di)點或(huo)地(di)(di)(di)釘相連(lian)，該回路(lu)可(ke)(ke)傳導脈(mo)(mo)沖電(dian)(dian)流，它可(ke)(ke)由識別(bie)儀上的(de)(de)表(biao)頭讀出(chu)，電(dian)(dian)流大小由環路(lu)電(dian)(dian)阻決(jue)定，環路(lu)電(dian)(dian)阻應盡可(ke)(ke)能(neng)小。  發射機(ji)(ji)與接(jie)收機(ji)(ji)開始正常(chang)工作(zuo)后，卡鉗線(xian)圈中感(gan)應的(de)(de)電(dian)(dian)壓在(zai)接(jie)收機(ji)(ji)表(biao)頭中顯(xian)示出(chu)來，表(biao)頭指(zhi)針(zhen)擺動(dong)方向可(ke)(ke)顯(xian)示電(dian)(dian)流方向，即只有(you)電(dian)(dian)流流出(chu)的(de)(de)這(zhe)根電(dian)(dian)纜(lan)指(zhi)針(zhen)向右偏(pian)并且擺幅(fu)較大，這(zhe)根就(jiu)是要(yao)(yao)找的(de)(de)電(dian)(dian)纜(lan)。所有(you)其它電(dian)(dian)纜(lan)只流過(guo)返(fan)回電(dian)(dian)流，指(zhi)針(zhen)向左(zuo)偏(pian)并且擺幅(fu)極小。接(jie)收機(ji)(ji)上的(de)(de)輸(shu)出(chu)調節旋鈕(niu)可(ke)(ke)調整(zheng)信號強度。

1.儀器供電

電纜識別儀(yi)主機由交(jiao)流220V供電。

2.卡鉗

卡鉗是一電流變換器，鉗口內部尺寸為120mm。卡鉗側面有一箭頭，它應指(zhi)向被測電纜的遠端。

當電(dian)(dian)(dian)(dian)流流過測試電(dian)(dian)(dian)(dian)纜，在卡鉗內感應出(chu)電(dian)(dian)(dian)(dian)壓，電(dian)(dian)(dian)(dian)壓幅度(du)由(you)電(dian)(dian)(dian)(dian)流強(qiang)度(du)決(jue)定(ding)，其極性(xing)由(you)電(dian)(dian)(dian)(dian)流方向決(jue)定(ding)。

3.安全測試

一定要進行以下(xia)安全測試，以避免造成人員傷亡或損壞電(dian)纜(lan)識別(bie)儀(yi)及其它設備。使用電(dian)纜(lan)識別(bie)儀(yi)時(shi)，要對(dui)被(bei)測電(dian)纜(lan)進行帶電(dian)檢查，并確保(bao)該電(dian)纜(lan)處于無電(dian)狀態。

將(jiang)儀(yi)器接入(ru)被測電(dian)纜前，要對(dui)其附近末(mo)加保(bao)護(hu)的儀(yi)器或(huo)電(dian)纜進行(xing)安(an)全檢查，并將(jiang)這些帶(dai)電(dian)部(bu)分(fen)用(yong)絕(jue)緣材(cai)料進行(xing)安(an)全保(bao)護(hu)。

準備測試

主機準備

連接：

1.在(zai)進行測試工作之前。

2.將被測(ce)電(dian)纜斷電(dian)。

3.其周圍環(huan)境應處于(yu)安全狀態。

4.發(fa)生器與被(bei)測(ce)電纜相(xiang)連。

5.紅色夾子(zi)與被識別(bie)電纜(lan)的(de)一根(gen)芯線或幾根(gen)芯線連(lian)到一起。將黑(hei)色夾子(zi)與地釘相連(lian)。

6. 將電纜(lan)遠端的芯線(xian)與地釘相(xiang)連。

7.將(jiang)電纜兩(liang)端的(de)鎧裝與地線(xian)斷開。

8.將電源線插(cha)入電源插(cha)座。

開機：

a.逆時針(zhen)方向調節輸出(chu)旋鈕(niu)到零(ling)。

b.打(da)開主(zhu)機電源(yuan)開關，對主(zhu)機供電。

c.緩慢調節(jie)輸(shu)出旋鈕，主機開始間斷向電(dian)纜發出脈(mo)動直流信號，使(shi)輸(shu)出脈(mo)動電(dian)流信號為10－20A之間即(ji)可。

接收機準備

9.緩(huan)慢調節靈敏度旋鈕。

10.使電表開始(shi)指(zhi)示。

11.注意傳感器插入電纜的方向及(ji)接收(shou)機表頭擺動幅(fu)度(du)的大小。