電流繼電器觸點動作時產生的火花要怎么消除？2020-05-29 15:42:00

觸點動作時產生的火花要怎么消(xiao)除(chu)？

由于電(dian)流繼電(dian)器觸(chu)(chu)(chu)點(dian)的(de)跳動或者開閉的(de)一(yi)瞬(shun)間均會(hui)引(yin)起感性負載的(de)變化，產(chan)生(sheng)氣體(ti)放(fang)(fang)(fang)電(dian)現(xian)象，但電(dian)流繼電(dian)器觸(chu)(chu)(chu)點(dian)通(tong)斷的(de)電(dian)流較小，觸(chu)(chu)(chu)點(dian)間不(bu)會(hui)出現(xian)電(dian)弧，但會(hui)出現(xian)“火(huo)花(hua)放(fang)(fang)(fang)電(dian)”，這是(shi)由于觸(chu)(chu)(chu)點(dian)電(dian)路(lu)中存在電(dian)感，則在斷開時電(dian)感上會(hui)出現(xian)過電(dian)壓(ya)，它(ta)與電(dian)源電(dian)壓(ya)一(yi)起加在觸(chu)(chu)(chu)點(dian)間隙(xi)上，使剛分開一(yi)點(dian)距離的(de)觸(chu)(chu)(chu)點(dian)間隙(xi)擊穿而放(fang)(fang)(fang)電(dian)。由于能量(liang)所限(xian)，只會(hui)產(chan)生(sheng)火(huo)花(hua)放(fang)(fang)(fang)電(dian)，觸(chu)(chu)(chu)點(dian)間存在的(de)電(dian)容與電(dian)感中能量(liang)的(de)交替(ti)轉換，使火(huo)花(hua)放(fang)(fang)(fang)電(dian)時隱時現(xian)，而成(cheng)(cheng)為一(yi)種高(gao)頻信號，通(tong)過高(gao)頻輻射(she)、導線(xian)傳遞及分布電(dian)容等途徑而串擾(rao)到(dao)相關電(dian)路(lu)中，造成(cheng)(cheng)干擾(rao)信號。再(zai)者火(huo)花(hua)放(fang)(fang)(fang)電(dian)對觸(chu)(chu)(chu)點(dian)也會(hui)造成(cheng)(cheng)損傷，而會(hui)降低觸(chu)(chu)(chu)點(dian)的(de)使用(yong)壽命，電(dian)火(huo)花(hua)會(hui)燒蝕觸(chu)(chu)(chu)點(dian)表(biao)面(mian)，使其表(biao)面(mian)不(bu)平造成(cheng)(cheng)接觸(chu)(chu)(chu)不(bu)良(liang)的(de)故障。

　　RC消火花電路

　　因此必須(xu)設(she)法消(xiao)(xiao)除電(dian)(dian)(dian)(dian)(dian)(dian)火(huo)(huo)花(hua)(hua)(hua)，實用的(de)(de)(de)消(xiao)(xiao)火(huo)(huo)花(hua)(hua)(hua)電(dian)(dian)(dian)(dian)(dian)(dian)路(lu)(lu)(lu)(lu)(lu)(lu)是(shi)RC消(xiao)(xiao)火(huo)(huo)花(hua)(hua)(hua)電(dian)(dian)(dian)(dian)(dian)(dian)路(lu)(lu)(lu)(lu)(lu)(lu)，如圖所示(shi)。圖中(zhong)虛線(xian)框內是(shi)一種半RC吸(xi)(xi)收電(dian)(dian)(dian)(dian)(dian)(dian)路(lu)(lu)(lu)(lu)(lu)(lu)，RC消(xiao)(xiao)火(huo)(huo)花(hua)(hua)(hua)電(dian)(dian)(dian)(dian)(dian)(dian)路(lu)(lu)(lu)(lu)(lu)(lu)基本作用原(yuan)理是(shi)，把(ba)R和C相串聯后(hou)再(zai)并聯在電(dian)(dian)(dian)(dian)(dian)(dian)流繼電(dian)(dian)(dian)(dian)(dian)(dian)器(qi)(qi)觸(chu)(chu)點(dian)的(de)(de)(de)兩端(duan)。使電(dian)(dian)(dian)(dian)(dian)(dian)感中(zhong)的(de)(de)(de)能量不通過觸(chu)(chu)點(dian)而(er)通過RC；它只吸(xi)(xi)收觸(chu)(chu)點(dian)斷開時(shi)產生(sheng)的(de)(de)(de)自(zi)感電(dian)(dian)(dian)(dian)(dian)(dian)勢。在電(dian)(dian)(dian)(dian)(dian)(dian)流繼電(dian)(dian)(dian)(dian)(dian)(dian)器(qi)(qi)觸(chu)(chu)點(dian)接通瞬間，由于RC被短路(lu)(lu)(lu)(lu)(lu)(lu)，所以(yi)沒有吸(xi)(xi)收作用，圖中(zhong)虛線(xian)框外是(shi)一種全吸(xi)(xi)收電(dian)(dian)(dian)(dian)(dian)(dian)路(lu)(lu)(lu)(lu)(lu)(lu)，在觸(chu)(chu)點(dian)斷開時(shi)自(zi)感電(dian)(dian)(dian)(dian)(dian)(dian)勢經過二極管(guan)V在負載rL上(shang)消(xiao)(xiao)耗掉。在實際應(ying)用中(zhong)選(xuan)擇以(yi)上(shang)電(dian)(dian)(dian)(dian)(dian)(dian)路(lu)(lu)(lu)(lu)(lu)(lu)中(zhong)的(de)(de)(de)一種就行了。但要(yao)注意的(de)(de)(de)是(shi)，RC參(can)數要(yao)選(xuan)擇適當，參(can)數主要(yao)靠實驗來(lai)決定，通常電(dian)(dian)(dian)(dian)(dian)(dian)容C可按負載電(dian)(dian)(dian)(dian)(dian)(dian)流1A/1μF選(xuan)擇。使用二極管(guan)時(shi)其正負極性(xing)應(ying)連接正確，且(qie)二極管(guan)V的(de)(de)(de)耐壓(ya)要(yao)夠。需要(yao)指出的(de)(de)(de)是(shi)RC消(xiao)(xiao)火(huo)(huo)花(hua)(hua)(hua)電(dian)(dian)(dian)(dian)(dian)(dian)路(lu)(lu)(lu)(lu)(lu)(lu)應(ying)緊靠電(dian)(dian)(dian)(dian)(dian)(dian)流繼電(dian)(dian)(dian)(dian)(dian)(dian)器(qi)(qi)觸(chu)(chu)點(dian)安裝(zhuang)，并盡量使連接線(xian)短些，以(yi)保證(zheng)消(xiao)(xiao)火(huo)(huo)花(hua)(hua)(hua)電(dian)(dian)(dian)(dian)(dian)(dian)路(lu)(lu)(lu)(lu)(lu)(lu)的(de)(de)(de)效果(guo)。

　　如某(mou)廠熱處理(li)爐的(de)(de)(de)(de)溫(wen)度自動控制(zhi)系統，用溫(wen)控儀(yi)(yi)（控制(zhi)輸出(chu)為電(dian)(dian)(dian)(dian)(dian)流繼(ji)(ji)電(dian)(dian)(dian)(dian)(dian)器(qi)(qi)(qi)的(de)(de)(de)(de)PID調節器(qi)(qi)(qi)）及中間電(dian)(dian)(dian)(dian)(dian)流繼(ji)(ji)電(dian)(dian)(dian)(dian)(dian)器(qi)(qi)(qi)來控制(zhi)接(jie)觸(chu)(chu)(chu)器(qi)(qi)(qi)的(de)(de)(de)(de)通(tong)、斷進而(er)(er)控制(zhi)電(dian)(dian)(dian)(dian)(dian)熱器(qi)(qi)(qi)。但在(zai)(zai)(zai)使(shi)(shi)用中由于(yu)(yu)溫(wen)度儀(yi)(yi)表(biao)波動大(da)，尤其(qi)控溫(wen)精度越(yue)高其(qi)波動越(yue)大(da)，致使(shi)(shi)中間電(dian)(dian)(dian)(dian)(dian)流繼(ji)(ji)電(dian)(dian)(dian)(dian)(dian)器(qi)(qi)(qi)動作(zuo)(zuo)(zuo)(zuo)頻(pin)繁(fan)，由于(yu)(yu)電(dian)(dian)(dian)(dian)(dian)流繼(ji)(ji)電(dian)(dian)(dian)(dian)(dian)器(qi)(qi)(qi)的(de)(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)觸(chu)(chu)(chu)點(dian)(dian)在(zai)(zai)(zai)接(jie)通(tong)的(de)(de)(de)(de)瞬(shun)間，觸(chu)(chu)(chu)點(dian)(dian)上(shang)將(jiang)有數(shu)倍于(yu)(yu)正常工作(zuo)(zuo)(zuo)(zuo)電(dian)(dian)(dian)(dian)(dian)流的(de)(de)(de)(de)沖擊(ji)，而(er)(er)在(zai)(zai)(zai)斷開(kai)瞬(shun)間，電(dian)(dian)(dian)(dian)(dian)路(lu)(lu)中儲存的(de)(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)能將(jiang)以火花的(de)(de)(de)(de)形式在(zai)(zai)(zai)觸(chu)(chu)(chu)點(dian)(dian)間釋放。電(dian)(dian)(dian)(dian)(dian)流繼(ji)(ji)電(dian)(dian)(dian)(dian)(dian)器(qi)(qi)(qi)觸(chu)(chu)(chu)點(dian)(dian)過(guo)于(yu)(yu)頻(pin)繁(fan)的(de)(de)(de)(de)動作(zuo)(zuo)(zuo)(zuo)造成電(dian)(dian)(dian)(dian)(dian)觸(chu)(chu)(chu)點(dian)(dian)的(de)(de)(de)(de)發(fa)熱、燒蝕、甚至熔(rong)焊(han)，修磨幾次(ci)就無法(fa)使(shi)(shi)用了(le)，只能更(geng)換(huan)電(dian)(dian)(dian)(dian)(dian)流繼(ji)(ji)電(dian)(dian)(dian)(dian)(dian)器(qi)(qi)(qi)。接(jie)觸(chu)(chu)(chu)器(qi)(qi)(qi)已(yi)由于(yu)(yu)經(jing)常流過(guo)數(shu)倍的(de)(de)(de)(de)工作(zuo)(zuo)(zuo)(zuo)電(dian)(dian)(dian)(dian)(dian)流而(er)(er)發(fa)熱，鐵芯由于(yu)(yu)頻(pin)繁(fan)動作(zuo)(zuo)(zuo)(zuo)使(shi)(shi)鐵芯位移和磁(ci)(ci)路(lu)(lu)氣隙增大(da)，而(er)(er)產生(sheng)很(hen)大(da)的(de)(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)噪聲。上(shang)述問題不僅增加了(le)維修工作(zuo)(zuo)(zuo)(zuo)量，有時還(huan)影響生(sheng)產，為此該廠對電(dian)(dian)(dian)(dian)(dian)路(lu)(lu)進行了(le)改造，使(shi)(shi)用RC消火花電(dian)(dian)(dian)(dian)(dian)路(lu)(lu)，RC電(dian)(dian)(dian)(dian)(dian)路(lu)(lu)選擇的(de)(de)(de)(de)參數(shu)是(shi)：C為100pF/1000V，R的(de)(de)(de)(de)為1.2kΩ/1W。把RC元件(jian)直接(jie)接(jie)在(zai)(zai)(zai)電(dian)(dian)(dian)(dian)(dian)流繼(ji)(ji)電(dian)(dian)(dian)(dian)(dian)器(qi)(qi)(qi)的(de)(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)觸(chu)(chu)(chu)點(dian)(dian)上(shang)，再就是(shi)設法(fa)減小接(jie)觸(chu)(chu)(chu)器(qi)(qi)(qi)的(de)(de)(de)(de)工作(zuo)(zuo)(zuo)(zuo)電(dian)(dian)(dian)(dian)(dian)流，采取這些措施后，電(dian)(dian)(dian)(dian)(dian)流繼(ji)(ji)電(dian)(dian)(dian)(dian)(dian)器(qi)(qi)(qi)的(de)(de)(de)(de)觸(chu)(chu)(chu)點(dian)(dian)使(shi)(shi)用壽(shou)命大(da)大(da)延長(chang)。效果明顯，在(zai)(zai)(zai)滿(man)足了(le)生(sheng)產要求(qiu)的(de)(de)(de)(de)同時，還(huan)減輕了(le)維修工作(zuo)(zuo)(zuo)(zuo)量，節約(yue)了(le)維修費(fei)用。

　　消除電流(liu)繼電器接點火花的方法(fa)

　　由于(yu)電(dian)(dian)(dian)(dian)(dian)(dian)流(liu)繼電(dian)(dian)(dian)(dian)(dian)(dian)器接(jie)(jie)點通斷的(de)電(dian)(dian)(dian)(dian)(dian)(dian)流(liu)較小，接(jie)(jie)點間(jian)不會出(chu)(chu)現電(dian)(dian)(dian)(dian)(dian)(dian)弧，但(dan)會出(chu)(chu)現“火(huo)(huo)花(hua)(hua)放(fang)電(dian)(dian)(dian)(dian)(dian)(dian)”，這是由于(yu)接(jie)(jie)點電(dian)(dian)(dian)(dian)(dian)(dian)路中(zhong)存在(zai)電(dian)(dian)(dian)(dian)(dian)(dian)感(gan)，則在(zai)斷開時(shi)電(dian)(dian)(dian)(dian)(dian)(dian)感(gan)上會出(chu)(chu)現過(guo)電(dian)(dian)(dian)(dian)(dian)(dian)壓，它與電(dian)(dian)(dian)(dian)(dian)(dian)源電(dian)(dian)(dian)(dian)(dian)(dian)壓一(yi)(yi)起(qi)加在(zai)接(jie)(jie)點間(jian)隙(xi)上，使剛分開一(yi)(yi)點距(ju)離(li)的(de)接(jie)(jie)點間(jian)隙(xi)擊(ji)穿而(er)放(fang)電(dian)(dian)(dian)(dian)(dian)(dian)。由于(yu)能量所限，只會產生火(huo)(huo)花(hua)(hua)放(fang)電(dian)(dian)(dian)(dian)(dian)(dian)，接(jie)(jie)點間(jian)存在(zai)的(de)電(dian)(dian)(dian)(dian)(dian)(dian)容與電(dian)(dian)(dian)(dian)(dian)(dian)感(gan)中(zhong)能量的(de)交替轉換，使火(huo)(huo)花(hua)(hua)放(fang)電(dian)(dian)(dian)(dian)(dian)(dian)時(shi)隱時(shi)現，而(er)成(cheng)(cheng)為(wei)一(yi)(yi)種高(gao)頻信號，再者火(huo)(huo)花(hua)(hua)放(fang)電(dian)(dian)(dian)(dian)(dian)(dian)對接(jie)(jie)點也會造成(cheng)(cheng)損傷，而(er)會降低使用(yong)壽(shou)命，因此必(bi)須(xu)設(she)法消除，實用(yong)的(de)消火(huo)(huo)花(hua)(hua)電(dian)(dian)(dian)(dian)(dian)(dian)路有(you)兩種。

一、其基本作用(yong)原理(li)是，使電感中的能量不通過(guo)接點而(er)通過(guo)rc；

二(er)、在斷開時(shi)經過二(er)極(ji)管v在負載r.l上消耗(hao)掉。在應用中選(xuan)擇(ze)一種就行了。但要注意(yi)的是(shi)，rc參(can)數要選(xuan)擇(ze)適當(dang)，參(can)數主要靠實驗來(lai)決定，通常電容c可按負載電流1a／1微(wei)法選(xuan)擇(ze)。使用二(er)極(ji)管時(shi)其正負極(ji)性應連接正確。