過與欠電流繼電器有什么主要區別？
過電(dian)流(liu)繼(ji)電(dian)器與欠電(dian)流(liu)繼(ji)電(dian)器的(de)區別：
一、過電流繼電器與欠電流繼電器的定義不同：
過電流繼(ji)電器的(de)定義是：
過(guo)(guo)流繼(ji)電(dian)(dian)器分(fen)(fen)為感應電(dian)(dian)磁式和集成電(dian)(dian)路(lu)型(xing)，具有定(ding)時限、反時限的(de)特(te)性，應用于電(dian)(dian)機(ji)、變壓器等主設(she)備(bei)以及(ji)輸(shu)(shu)配(pei)(pei)電(dian)(dian)系(xi)統(tong)的(de)繼(ji)電(dian)(dian)保護(hu)回(hui)路(lu)中。當主設(she)備(bei)或(huo)(huo)輸(shu)(shu)配(pei)(pei)電(dian)(dian)系(xi)統(tong)出(chu)現過(guo)(guo)負荷及(ji)短路(lu)故(gu)障時，該繼(ji)電(dian)(dian)器能按預定(ding)的(de)時限可靠動作或(huo)(huo)發出(chu)信號(hao)，切除(chu)故(gu)障部(bu)分(fen)(fen)，保證主設(she)備(bei)及(ji)輸(shu)(shu)配(pei)(pei)電(dian)(dian)系(xi)統(tong)的(de)安(an)全。
欠(qian)電流(liu)繼電器定義是：
當通過繼(ji)電(dian)(dian)(dian)(dian)器(qi)的(de)電(dian)(dian)(dian)(dian)流(liu)(liu)減小(xiao)到低于其整定(ding)值時就動作的(de)繼(ji)電(dian)(dian)(dian)(dian)器(qi)，稱(cheng)為欠(qian)(qian)電(dian)(dian)(dian)(dian)流(liu)(liu)繼(ji)電(dian)(dian)(dian)(dian)器(qi)。當檢(jian)測(ce)的(de)電(dian)(dian)(dian)(dian)流(liu)(liu)大于欠(qian)(qian)電(dian)(dian)(dian)(dian)流(liu)(liu)設定(ding)值時，欠(qian)(qian)電(dian)(dian)(dian)(dian)流(liu)(liu)輸出繼(ji)電(dian)(dian)(dian)(dian)器(qi)吸(xi)合，否則輸出繼(ji)電(dian)(dian)(dian)(dian)器(qi)釋(shi)放。欠(qian)(qian)電(dian)(dian)(dian)(dian)流(liu)(liu)設定(ding)值通過面板按鍵設置，設置范(fan)(fan)圍(wei)(wei)為測(ce)量(liang)范(fan)(fan)圍(wei)(wei)，控制精度(du)高。面板有(you)欠(qian)(qian)電(dian)(dian)(dian)(dian)流(liu)(liu)指示燈，內部(bu)有(you)報(bao)警蜂鳴(ming)器(qi)。
二、過電流、欠電流繼電器的工作原理不同：
過電流(liu)繼電器的工作(zuo)原理：
1、電(dian)(dian)(dian)磁式過(guo)流(liu)(liu)繼電(dian)(dian)(dian)器的工作原(yuan)理(li)是復合式的，由(you)公用(yong)(yong)一個線圈的感(gan)應(ying)式和電(dian)(dian)(dian)磁式的兩個元(yuan)件組成(cheng)。當(dang)繼電(dian)(dian)(dian)器的線圈通以交流(liu)(liu)電(dian)(dian)(dian)流(liu)(liu)時(shi)，則在鐵芯的遮(zhe)(zhe)蔽(bi)與未遮(zhe)(zhe)蔽(bi)部分產生兩個具有(you)(you)一定相(xiang)位差的磁通。此磁通與其在圓盤中(zhong)感(gan)應(ying)的渦流(liu)(liu)相(xiang)互作用(yong)(yong)，在圓盤上產生一轉(zhuan)矩(ju)。在20%～40%的動(dong)作電(dian)(dian)(dian)流(liu)(liu)整定值下(xia)，圓盤開始旋轉(zhuan)。此時(shi)由(you)于扇齒與蝸桿沒(mei)有(you)(you)咬(yao)合，故繼電(dian)(dian)(dian)器不(bu)動(dong)作；
2、當線圈中(zhong)的(de)(de)(de)電(dian)(dian)流(liu)增(zeng)大至整(zheng)定(ding)電(dian)(dian)流(liu)時(shi)，電(dian)(dian)磁力(li)(li)矩大于(yu)(yu)彈簧(huang)的(de)(de)(de)反作(zuo)(zuo)用力(li)(li)矩框(kuang)架(jia)轉動(dong)，使(shi)扇齒(chi)與蝸桿咬(yao)合，扇齒(chi)上升(sheng)。此(ci)時(shi)繼(ji)電(dian)(dian)器(qi)的(de)(de)(de)動(dong)鐵在扇齒(chi)頂桿的(de)(de)(de)推(tui)動(dong)下，使(shi)導(dao)磁鐵右邊(bian)(bian)氣隙減少(shao)，左邊(bian)(bian)氣隙增(zeng)大，因而動(dong)鐵被(bei)導(dao)磁鐵吸合，使(shi)繼(ji)電(dian)(dian)器(qi)觸點動(dong)作(zuo)(zuo)。當繼(ji)電(dian)(dian)器(qi)線圈中(zhong)的(de)(de)(de)電(dian)(dian)流(liu)為整(zheng)定(ding)值時(shi)，感應(ying)元(yuan)件的(de)(de)(de)動(dong)作(zuo)(zuo)時(shi)限與電(dian)(dian)流(liu)的(de)(de)(de)平方成反比。隨著電(dian)(dian)流(liu)的(de)(de)(de)增(zeng)加，導(dao)磁體飽和，動(dong)作(zuo)(zuo)時(shi)限逐漸趨于(yu)(yu)定(ding)值；
3、當線圈中的(de)電(dian)(dian)(dian)流(liu)大(da)到某一電(dian)(dian)(dian)流(liu)倍數時，電(dian)(dian)(dian)磁(ci)元件(jian)瞬時動(dong)作(zuo)，因而繼(ji)電(dian)(dian)(dian)器(qi)的(de)動(dong)作(zuo)時限具有有限反延(yan)時的(de)特(te)性。繼(ji)電(dian)(dian)(dian)器(qi)具有若干抽頭，用(yong)以調整感應元件(jian)與(yu)電(dian)(dian)(dian)磁(ci)元件(jian)的(de)動(dong)作(zuo)電(dian)(dian)(dian)流(liu)。另外(wai)用(yong)倍流(liu)螺釘改變動(dong)鐵與(yu)電(dian)(dian)(dian)磁(ci)鐵之間(jian)的(de)氣隙來(lai)調整電(dian)(dian)(dian)磁(ci)元件(jian)動(dong)作(zuo)電(dian)(dian)(dian)流(liu)。繼(ji)電(dian)(dian)(dian)器(qi)具有調整感應元件(jian)動(dong)作(zuo)時間(jian)整定值的(de)機構(gou)及主觸點(dian)動(dong)作(zuo)的(de)信(xin)號(hao)牌(pai)。用(yong)手旋轉返回(hui)機構(gou)，可使信(xin)號(hao)牌(pai)返回(hui)，并不需取下外(wai)殼。
欠電流繼電器的工作原理：
在電(dian)(dian)(dian)路正常工作時(shi)，欠電(dian)(dian)(dian)流(liu)(liu)(liu)繼(ji)電(dian)(dian)(dian)器的(de)(de)銜鐵與鐵芯始終是吸(xi)合的(de)(de)。只有(you)當電(dian)(dian)(dian)流(liu)(liu)(liu)降至低于整定值(zhi)時(shi)，欠電(dian)(dian)(dian)流(liu)(liu)(liu)繼(ji)電(dian)(dian)(dian)器釋放，發出(chu)信號，從而改變(bian)電(dian)(dian)(dian)路的(de)(de)狀態(tai)。欠電(dian)(dian)(dian)流(liu)(liu)(liu)繼(ji)電(dian)(dian)(dian)器的(de)(de)吸(xi)引電(dian)(dian)(dian)流(liu)(liu)(liu)一般為線圈額定電(dian)(dian)(dian)流(liu)(liu)(liu)的(de)(de)0.3～0.65倍，釋放電(dian)(dian)(dian)流(liu)(liu)(liu)為額定電(dian)(dian)(dian)流(liu)(liu)(liu)的(de)(de)0.1～0.2倍。
三、過電流、欠電流繼電器的圖形符號不同：
1、根據線(xian)(xian)(xian)(xian)圈中電(dian)流(liu)(liu)的大小(xiao)而(er)接通和斷(duan)開電(dian)路(lu)的繼電(dian)器稱為電(dian)流(liu)(liu)繼電(dian)器。使用(yong)時電(dian)流(liu)(liu)繼電(dian)器的線(xian)(xian)(xian)(xian)圈與負載串聯，其(qi)線(xian)(xian)(xian)(xian)圈的匝數少(shao)而(er)線(xian)(xian)(xian)(xian)徑(jing)粗。常用(yong)的有(you)欠電(dian)流(liu)(liu)繼電(dian)器和過電(dian)流(liu)(liu)繼電(dian)器兩(liang)種；
2、欠電(dian)流繼(ji)電(dian)器：電(dian)路(lu)正常工作時，欠電(dian)流繼(ji)電(dian)器吸合，當電(dian)路(lu)電(dian)流減(jian)小到某(mou)一整(zheng)定值以下時（10％～20％IN），欠電(dian)流繼(ji)電(dian)器釋放(fang) ，對(dui)電(dian)路(lu)實(shi)現欠電(dian)流保護；
3、過(guo)電(dian)(dian)(dian)流(liu)繼電(dian)(dian)(dian)器(qi)：電(dian)(dian)(dian)路正常工(gong)作(zuo)(zuo)時(shi)，過(guo)電(dian)(dian)(dian)流(liu)繼電(dian)(dian)(dian)器(qi)不動作(zuo)(zuo)，當電(dian)(dian)(dian)路電(dian)(dian)(dian)流(liu)超過(guo)某一整定值(zhi)時(shi)（一般為110％～400％IN），過(guo)電(dian)(dian)(dian)流(liu)繼電(dian)(dian)(dian)器(qi)吸合，對電(dian)(dian)(dian)路實(shi)現(xian)過(guo)電(dian)(dian)(dian)流(liu)保護。
四、過電流、欠電流繼電器是如何工作的？
過電(dian)流(liu)繼(ji)電(dian)器和欠電(dian)流(liu)繼(ji)電(dian)器，在正(zheng)常電(dian)流(liu)下(xia)都是(shi)工作的嘛？
1、過電(dian)(dian)流(liu)(liu)繼電(dian)(dian)器(qi)(qi)在(zai)正(zheng)常(chang)電(dian)(dian)流(liu)(liu)下(xia)都不工(gong)作，或者說，正(zheng)常(chang)時，銜鐵是(shi)釋放的。這樣做可(ke)以(yi)延長繼電(dian)(dian)器(qi)(qi)的使(shi)用壽命，還(huan)可(ke)節約(yue)控制用電(dian)(dian)。因此(ci)繼電(dian)(dian)器(qi)(qi)處于(yu)(yu)保護狀(zhuang)態的時間相對(dui)于(yu)(yu)正(zheng)常(chang)工(gong)作時間很短；
2、上述方式(shi)(shi)是(shi)所有(you)保護類繼電(dian)器希望采取的方式(shi)(shi)，但是(shi)欠電(dian)流繼電(dian)器不能設計(ji)成這樣，因(yin)為(wei)電(dian)流很小(xiao)或沒有(you)時，繼電(dian)器只能釋(shi)放(fang)銜鐵，而無法吸住銜鐵；
五、上面我們了解了，正常電流時的繼電器的特點！那么過電流繼電器和欠電流繼電器的工作特點又是什么？
1、過(guo)電(dian)流繼(ji)電(dian)器，用于過(guo)電(dian)流保(bao)護，當電(dian)流達到設定值時吸合(he)；
2、欠電流(liu)繼電器，一般(ban)用于直流(liu)電動機磁場的弱(ruo)磁場保護(hu)，以防電動機超速，正常工作是吸合的，當電流(liu)小于設定值時釋放；
過電流繼(ji)電器與欠電流繼(ji)電器的區(qu)別：
過電流(liu)繼電器，用于過電流(liu)保護，當電流(liu)達到設(she)定(ding)值時吸合；
欠(qian)電流繼電器，一(yi)般用于直(zhi)流電動機磁(ci)場的弱磁(ci)場保(bao)護，以防電動機超速，正常工(gong)作是(shi)吸(xi)合的，當電流小于設定值(zhi)時釋(shi)放。
