一、測電筆有什么用途
1、用來判別物體是否帶電。它的內部構造是一只有兩個電極的燈泡,泡(pao)內(nei)充有氖(nai)氣,俗(su)稱氖(nai)泡(pao),它(ta)的(de)(de)(de)一(yi)極接(jie)到筆尖,另一(yi)極串聯一(yi)只高電(dian)(dian)(dian)(dian)阻后接(jie)到筆的(de)(de)(de)另一(yi)端。當氖(nai)泡(pao)的(de)(de)(de)兩(liang)(liang)極間(jian)(jian)電(dian)(dian)(dian)(dian)壓(ya)達(da)到一(yi)定值(zhi)時,兩(liang)(liang)極間(jian)(jian)便產生輝光(guang),輝光(guang)強弱(ruo)與兩(liang)(liang)極間(jian)(jian)電(dian)(dian)(dian)(dian)壓(ya)成正比。當帶電(dian)(dian)(dian)(dian)體對地電(dian)(dian)(dian)(dian)壓(ya)大于氖(nai)泡(pao)起始的(de)(de)(de)輝光(guang)電(dian)(dian)(dian)(dian)壓(ya),而將測電(dian)(dian)(dian)(dian)筆的(de)(de)(de)筆尖端接(jie)觸它(ta)時,另一(yi)端則通(tong)過人體接(jie)地,所(suo)以測電(dian)(dian)(dian)(dian)筆會發光(guang)。測電(dian)(dian)(dian)(dian)筆中電(dian)(dian)(dian)(dian)阻的(de)(de)(de)作用(yong)是用(yong)來限制(zhi)流過人體的(de)(de)(de)電(dian)(dian)(dian)(dian)流,以免發生危險(xian)。
2、可以用(yong)來進行(xing)低壓(ya)核(he)相(xiang),測(ce)量線(xian)(xian)路中任何導線(xian)(xian)之間(jian)是否同(tong)相(xiang)或異(yi)相(xiang)。具體方法是:站在一(yi)個(ge)與(yu)大地絕緣的(de)物體上,雙手各(ge)執一(yi)支測(ce)電(dian)(dian)筆(bi)(bi),然后在待測(ce)的(de)兩(liang)根導線(xian)(xian)上進行(xing)測(ce)試,如果兩(liang)根測(ce)電(dian)(dian)筆(bi)(bi)發光很亮,則這兩(liang)根導線(xian)(xian)為異(yi)相(xiang);反之,則為同(tong)相(xiang),它是利用(yong)測(ce)電(dian)(dian)筆(bi)(bi)中氖泡兩(liang)極(ji)間(jian)電(dian)(dian)壓(ya)差值與(yu)其發光強弱成正比的(de)原理來進行(xing)判別的(de)。
3、可以(yi)用來(lai)判(pan)別交(jiao)(jiao)流(liu)(liu)電(dian)(dian)和(he)直(zhi)流(liu)(liu)電(dian)(dian)。在用測(ce)電(dian)(dian)筆進行測(ce)試時(shi),如果測(ce)電(dian)(dian)筆氖泡中(zhong)的兩個極都發光(guang),就是交(jiao)(jiao)流(liu)(liu)電(dian)(dian);如果兩個極中(zhong)只有一個極發光(guang),則(ze)是直(zhi)流(liu)(liu)電(dian)(dian)。
4、可以判(pan)斷直流電的(de)(de)正(zheng)、負(fu)極。將測電筆接在直流電路中測試,氖(nai)泡發亮(liang)的(de)(de)那一極就是(shi)正(zheng)極,不發亮(liang)的(de)(de)一極是(shi)負(fu)極。
5、可(ke)用(yong)來判(pan)斷直流(liu)(liu)是(shi)(shi)否接地(di)(di)(di)(di)。在對地(di)(di)(di)(di)絕緣的(de)(de)直流(liu)(liu)系統(tong)(tong)(tong)中(zhong),可(ke)站在地(di)(di)(di)(di)上用(yong)測電(dian)筆(bi)接觸直流(liu)(liu)系統(tong)(tong)(tong)中(zhong)的(de)(de)正(zheng)極(ji)或負極(ji),如(ru)(ru)果測電(dian)筆(bi)氖(nai)泡不(bu)亮(liang),則(ze)沒有(you)接地(di)(di)(di)(di)現象。如(ru)(ru)果氖(nai)泡發亮(liang),則(ze)說明有(you)接地(di)(di)(di)(di)現象,其發亮(liang)如(ru)(ru)在筆(bi)尖端,則(ze)說明為(wei)正(zheng)極(ji)接地(di)(di)(di)(di)。如(ru)(ru)發亮(liang)在手指端,則(ze)為(wei)負極(ji)接地(di)(di)(di)(di)。但是(shi)(shi)必須指出(chu)的(de)(de)是(shi)(shi)在帶有(you)接地(di)(di)(di)(di)監察繼(ji)電(dian)器的(de)(de)直流(liu)(liu)系統(tong)(tong)(tong)中(zhong),不(bu)可(ke)采用(yong)此(ci)方(fang)法判(pan)斷直流(liu)(liu)系統(tong)(tong)(tong)是(shi)(shi)否發生(sheng)接地(di)(di)(di)(di)。
二、測電筆的種類有哪些
1、按照測量電壓的高低分
高壓測(ce)電筆:用于10kv及以上項目作業時用,為電工的日常檢測(ce)用具;
低壓測(ce)電(dian)筆:用于線(xian)電(dian)壓500V及以(yi)下項目(mu)的(de)帶(dai)電(dian)體檢測(ce)。
弱電(dian)(dian)測(ce)電(dian)(dian)筆:用于電(dian)(dian)子產品的測(ce)試,一般測(ce)試電(dian)(dian)壓為(wei)6v--24v.為(wei)了便于使(shi)用,電(dian)(dian)筆尾部常(chang)帶有一根帶夾(jia)子的引出導線。
2、按照接觸方式分
接觸(chu)式試(shi)電筆:通過接觸(chu)帶電體,獲得電信號(hao)的檢測(ce)工具(ju)。通常形(xing)狀有(you)一(yi)字(zi)螺(luo)絲刀式,兼試(shi)電筆和一(yi)字(zi)螺(luo)絲刀用;鋼(gang)筆式,直接在液晶(jing)窗口顯示(shi)測(ce)量數(shu)據。
感應式試電筆:采用感應式測(ce)試,無需(xu)物(wu)理接觸,可檢查控制線、導體和插座(zuo)上(shang)的(de)電壓(ya)或沿導線檢查斷路位置。可以極大限度地保障檢測(ce)人(ren)員(yuan)的(de)人(ren)身(shen)安(an)全。
3、氖管式測電筆
氖管式(shi)測電(dian)(dian)筆又稱電(dian)(dian)筆,用來檢驗導(dao)線、電(dian)(dian)器和(he)電(dian)(dian)氣(qi)設備的金(jin)屬(shu)外殼是否帶電(dian)(dian)。這種電(dian)(dian)筆分為(wei)筆式(shi)和(he)螺絲刀式(shi)兩種形式(shi)。
4、數顯式測電筆
數顯式(shi)測(ce)電(dian)筆(bi)又稱(cheng)為感應式(shi)測(ce)電(dian)筆(bi)。這種電(dian)筆(bi)不僅可以(yi)測(ce)試物體是否帶電(dian),還能(neng)顯示出(chu)大致的電(dian)壓范圍。有些數顯式(shi)測(ce)電(dian)筆(bi)可以(yi)檢驗出(chu)絕(jue)緣導線斷線位置。