PILZ繼電器電壓工作有著怎樣的特殊要求
PILZ繼電器的技術條件般對線圈的電壓都給出工作電壓、吸合電壓、釋放電壓。要保證繼電器的正常工作,在電路連接時,定要保證在任何情況下都要使給定的三個電壓滿足技術條件規定的數值。否則,繼電器無法正常轉換。下面介紹個連接不正確的實例。
PILZ繼電器設計者想用3支工作電壓為6V的JRC—5M小型電磁繼電器和兩支開關組成的控制電路。
要求K1閉合時,J1繼電器工作;K2閉合時J3繼電器工作;當K1、K2同時閉合時,PILZ繼電器同時工作;當K1、K2同時打開時,J1、J2、J3繼電器同時不工作。我們從圖中可以看出,PILZ繼電器的工作條件都可滿足,線圈所加的電壓為6V,大于該繼電器的吸合電壓,符合工作電壓條件。但是,當K1、K2在此情況下打開時,繼電器J1、J2、J3不能恢復到不工作狀態。
不正確的PILZ繼電器連接是因為此時J1、J2、J3繼圈與6V電流形成串聯回路,此時,每個線圈的電壓為6V電源電壓的1/3(2V),而該繼電器的釋放電壓≤0.5V,所以PILZ繼電器仍處在工作狀態,達不到設計者的要求。
PILZ繼電器在使用時的注意事項有哪些?下面起來了解下:
額定工作電壓:是指繼電器正常工作時線圈所需要的電壓,繼電器也就是控制電路的控制電壓。根據繼電器的型號不同,可以是交流電壓,也可以是直流電壓。
直流電阻:是指繼電器中線圈的直流電阻,可以通過萬用表測量。
吸合電流:是指繼電器能夠產生吸合動作的zui小電流。在正常使用時,給定的電流必須略大于吸合電流,這樣繼電器才能穩定地工作。而對于線圈所加的工作電壓,般不要超過額定工作電壓的1.5倍,否則會產生較大的電流而把線圈燒毀。
PILZ繼電器釋放電流:是指PILZ繼電器產生釋放動作的zui大電流。當繼電器吸合狀態的電流減小到定程度時,繼電器就會恢復到未通電的釋放狀態。這時的電流遠遠小于吸合電流。
PILZ繼電器觸點切換電壓和電流:是指繼電器允許加載的電壓和電流。它決定了繼電器能控制電壓和電流的大小,使用時不能超過此值,否則很容易損壞繼電器的觸點。
主要是為了保護晶體管等驅動元器件。當圖中晶體管VT由導通變為截止時,流經繼電器線圈的電流將迅速減小,這時線圈會產生很高的自感電動勢與電源電壓疊加后加在VT的c、e兩極間,會使晶體管擊穿,并聯上二極管后,即可將線圈的自感電動勢鉗位于二極管的正向導通電壓,此值硅管約0.7V,鍺管約0.2V,從而避免擊穿晶體管等驅動元器件。并聯二極管時定要注意二極管的極性不可接反,否則容易損壞晶體管等驅動元器件。
形式二:PILZ繼電器并聯RC電路
PILZ繼電器電路閉合后,當電流穩定時RC電路不起作用,斷開電路時,繼電器線圈由于自感而產生感應電動勢,經RC電路放電,使線圈中電流衰減放慢,從而延長了繼電器銜鐵釋放時間,起到延時作用。
形式三:PILZ繼電器串聯RC電路
這(zhe)種(zhong)形式主要應用(yong)(yong)于繼(ji)(ji)電(dian)(dian)(dian)(dian)(dian)(dian)器的(de)額(e)定(ding)工作(zuo)電(dian)(dian)(dian)(dian)(dian)(dian)壓低于電(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)電(dian)(dian)(dian)(dian)(dian)(dian)壓的(de)電(dian)(dian)(dian)(dian)(dian)(dian)路(lu)中。當電(dian)(dian)(dian)(dian)(dian)(dian)路(lu)閉(bi)合(he)時(shi)(shi)(shi),PILZ繼(ji)(ji)電(dian)(dian)(dian)(dian)(dian)(dian)器線(xian)圈(quan)(quan)由于自感現象會產生電(dian)(dian)(dian)(dian)(dian)(dian)動勢阻礙線(xian)圈(quan)(quan)中電(dian)(dian)(dian)(dian)(dian)(dian)流的(de)增大(da),從而延(yan)長了(le)吸合(he)時(shi)(shi)(shi)間(jian),串聯(lian)上RC電(dian)(dian)(dian)(dian)(dian)(dian)路(lu)后(hou)則可(ke)(ke)以(yi)縮短吸合(he)時(shi)(shi)(shi)間(jian)。原(yuan)理是電(dian)(dian)(dian)(dian)(dian)(dian)路(lu)閉(bi)合(he)的(de)瞬間(jian),電(dian)(dian)(dian)(dian)(dian)(dian)容C兩(liang)端電(dian)(dian)(dian)(dian)(dian)(dian)壓不能(neng)突變可(ke)(ke)視為短路(lu),這(zhe)樣就將比繼(ji)(ji)電(dian)(dian)(dian)(dian)(dian)(dian)器線(xian)圈(quan)(quan)額(e)定(ding)工作(zuo)電(dian)(dian)(dian)(dian)(dian)(dian)壓高的(de)電(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)電(dian)(dian)(dian)(dian)(dian)(dian)壓加(jia)到線(xian)圈(quan)(quan)上,從而加(jia)快了(le)線(xian)圈(quan)(quan)中電(dian)(dian)(dian)(dian)(dian)(dian)流增大(da)的(de)速(su)度,使繼(ji)(ji)電(dian)(dian)(dian)(dian)(dian)(dian)器迅速(su)吸合(he)。電(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)穩定(ding)之(zhi)后(hou)電(dian)(dian)(dian)(dian)(dian)(dian)容C不起(qi)作(zuo)用(yong)(yong),電(dian)(dian)(dian)(dian)(dian)(dian)阻R起(qi)限(xian)流作(zuo)用(yong)(yong)。
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