1、短(duan)路(lu)電流(liu)沿著預期(qi)短(duan)路(lu)電流(liu)的(de)指數曲線，從0沿較高(gao)梯度升高(gao)至(zhi)瞬時(shi)整定(ding)脫(tuo)扣電流(liu)值，時(shi)間小(xiao)于0.5-4ms。
2、脫扣(kou)器(qi)動(dong)作(zuo)以后，觸頭經過(guo)開關(guan)機構固(gu)有動(dong)作(zuo)時間(jian)(jian)斷(duan)開，此間(jian)(jian)電(dian)流繼(ji)續(xu)上(shang)升(sheng)，時間(jian)(jian)大約持續(xu)1-4ms。
3、在冷發(fa)射(she)，熱(re)發(fa)射(she)作用下產生電弧(hu)，電弧(hu)拉(la)長(chang)，并在弧(hu)柱中(zhong)熱(re)游離(li)，熱(re)碰撞。氣體(ti)游離(li)速度加快，產生較(jiao)大熱(re)量及壓力時間持續大約0.3-6ms。
4、直流斷路器在動，靜觸頭之間有(you)永久磁(ci)(ci)鐵或電(dian)(dian)磁(ci)(ci)線圈(quan)，并(bing)產生磁(ci)(ci)場，磁(ci)(ci)通比較集中，它經鐵心(xin)導磁(ci)(ci)夾板進入滅弧(hu)(hu)空間，并(bing)和(he)滅弧(hu)(hu)片形成一(yi)層閉(bi)合磁(ci)(ci)路，使電(dian)(dian)弧(hu)(hu)在強磁(ci)(ci)場作用(yong)下(xia)迅速(su)由觸頭經引(yin)弧(hu)(hu)角引(yin)向滅弧(hu)(hu)窄縫。
5、磁場滅弧(hu)室帶(dai)滅弧(hu)罩，由(you)耐弧(hu)塑料制作(zuo)，它的作(zuo)用：
一是引導電弧縱向(xiang)吹出；
二是使電弧(hu)與滅弧(hu)室的(de)絕緣壁接(jie)觸，從而迅速冷(leng)卻，增強去游(you)離作用，提高弧(hu)柱(zhu)電壓降，迫使電弧(hu)熄(xi)滅；三(san)是產生惰性氣體，幫助(zhu)滅弧(hu)。窄縫可將(jiang)電弧(hu)柱直接壓縮，使電弧(hu)同縫壁緊(jin)密接觸，加強冷卻和(he)去游離(li)作用(yong)。
柵(zha)(zha)片(pian)(pian)間(jian)(jian)是絕緣的，其作用(yong)能(neng)導出(chu)電(dian)(dian)(dian)(dian)(dian)(dian)弧(hu)(hu)(hu)的熱(re)量(liang)，以(yi)提高電(dian)(dian)(dian)(dian)(dian)(dian)弧(hu)(hu)(hu)的弧(hu)(hu)(hu)柱(zhu)壓降。同(tong)時柵(zha)(zha)片(pian)(pian)將電(dian)(dian)(dian)(dian)(dian)(dian)弧(hu)(hu)(hu)分割(ge)成一段段的電(dian)(dian)(dian)(dian)(dian)(dian)弧(hu)(hu)(hu)，每一柵(zha)(zha)片(pian)(pian)是這(zhe)些短(duan)弧(hu)(hu)(hu)和電(dian)(dian)(dian)(dian)(dian)(dian)極，也就有許(xu)多個陽(yang)極壓降和陰極壓降，近極處的電(dian)(dian)(dian)(dian)(dian)(dian)弧(hu)(hu)(hu)電(dian)(dian)(dian)(dian)(dian)(dian)壓加弧(hu)(hu)(hu)柱(zhu)的電(dian)(dian)(dian)(dian)(dian)(dian)壓降足夠(gou)大時，電(dian)(dian)(dian)(dian)(dian)(dian)源電(dian)(dian)(dian)(dian)(dian)(dian)壓就不能(neng)維(wei)持電(dian)(dian)(dian)(dian)(dian)(dian)弧(hu)(hu)(hu)，因而滅弧(hu)(hu)(hu)，電(dian)(dian)(dian)(dian)(dian)(dian)弧(hu)(hu)(hu)熄滅時間(jian)(jian)大約(yue)需2-30ms。
