火花機的工作原理：電(dian)源提供電(dian)壓(ya)給(gei)各用電(dian)元件。同時通過(guo)其電(dian)壓(ya)調(diao)(diao)整器(qi)（內含高頻(pin)(pin)(pin)振(zhen)蕩電(dian)路，用來(lai)產生高頻(pin)(pin)(pin)電(dian)壓(ya)）調(diao)(diao)整其工作電(dian)壓(ya)，并經高壓(ya)變壓(ya)器(qi)變壓(ya)后，提供給(gei)試驗電(dian)極（鏈珠）高頻(pin)(pin)(pin)高壓(ya)。

需要(yao)指出(chu)的(de)是(shi)試驗(yan)電(dian)(dian)(dian)(dian)(dian)(dian)極處的(de)電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)雖然很(hen)高，但(dan)電(dian)(dian)(dian)(dian)(dian)(dian)流卻很(hen)小（一般在(zai)50mA以(yi)下）。當被測(ce)電(dian)(dian)(dian)(dian)(dian)(dian)線經過(guo)試驗(yan)電(dian)(dian)(dian)(dian)(dian)(dian)極時(shi)：如(ru)果(guo)電(dian)(dian)(dian)(dian)(dian)(dian)線絕緣(yuan)性(xing)良(liang)好(hao)，電(dian)(dian)(dian)(dian)(dian)(dian)線中(zhong)會(hui)產(chan)生(sheng)(sheng)穩定的(de)感應電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)，不存(cun)在(zai)電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)差；但(dan)當絕緣(yuan)層出(chu)現缺陷(xian)時(shi)（如(ru)：漏銅、有氣孔、嚴重偏心等(deng)），高頻高電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)就會(hui)對金屬導體放(fang)電(dian)(dian)(dian)(dian)(dian)(dian)（這(zhe)是(shi)高頻高電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)的(de)特性(xing)）。因電(dian)(dian)(dian)(dian)(dian)(dian)流很(hen)小，電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)將會(hui)極劇減小。產(chan)生(sheng)(sheng)電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)差。這(zhe)時(shi)擊穿(chuan)檢測(ce)就會(hui)將其電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)與基準電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)進行比較(jiao)。并將其電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)差放(fang)大，傳(chuan)送給(gei)報(bao)警顯(xian)示電(dian)(dian)(dian)(dian)(dian)(dian)路，發出(chu)報(bao)警。

根據以上原理，我們(men)可(ke)以解釋不接地的(de)時候為什(shen)么(me)可(ke)以報(bao)警：不接地時只對漏(lou)銅(tong)(tong)嚴(yan)重，牽引速度較慢的(de)線(xian)起作(zuo)用。因為對漏(lou)銅(tong)(tong)嚴(yan)重，速度較慢的(de)線(xian)，高(gao)頻高(gao)電壓可(ke)以充分對金屬導體放電，產生可(ke)檢(jian)測電壓差。但對那些有氣孔、嚴(yan)重偏心還(huan)未漏(lou)銅(tong)(tong)，牽引速度較快的(de)線(xian)，或者(zhe)可(ke)能(neng)因放電不充分而檢(jian)測不出來。

如果我們對火花機接地(di)(di)端子(zi)和(he)芯(xin)線(xian)另一端接地(di)(di)，這樣對那(nei)些有(you)氣孔、嚴重偏心(xin)還(huan)未漏(lou)銅，牽引速度較(jiao)快的(de)線(xian)放(fang)電時，就(jiu)可(ke)通過(guo)大地(di)(di)形成閉合回路加快放(fang)電，以保(bao)證其(qi)產生可(ke)檢測壓差。防止(zhi)漏(lou)測。這里要(yao)指出的(de)是，通過(guo)大地(di)(di)形成閉合回路（即短路）時，火花機內部有(you)短路限(xian)流器可(ke)保(bao)證安全。鏡(jing)面火花機

通過以上分析我(wo)們可總結(jie)火花機接地的原因：

1.火(huo)(huo)花機(ji)箱(xiang)體(ti)接地是為了保(bao)證人體(ti)安全：因為任何電(dian)器都(dou)有(you)發生漏電(dian)的可能。當火(huo)(huo)花機(ji)箱(xiang)體(ti)接地在其發生漏電(dian)時，漏電(dian)可直接導入大(da)地，保(bao)證人體(ti)安全。

2.火(huo)花機(ji)接地端子和芯線(xian)另一端接地，讓(rang)電流能通過導體(ti)接入大(da)地，電流形成閉合回(hui)路，使記數準確(que)，以防(fang)止漏測。

在(zai)此建議(yi)在(zai)使用(yong)火花(hua)機的時候應注意以(yi)下幾點：

1.火花機箱體一定要接地。

2.火(huo)花機接地(di)端(duan)子和芯線另(ling)一端(duan)（即芯線軸端(duan)）一定要接地(di)。

3.火花機的電壓設定值要適當比標準(zhun)大一點。

4.收線速度不要太大(da)。