在埋弧焊焊接過程中，維持電弧穩定燃燒，以及保持焊接參數基本不變是保證焊接接頭質量的基本要求。對此可通過以下兩種方法來實現。

1. 焊絲的送進(jin)按預選定的速度等(deng)速進(jin)入(ru)焊接區

  工作原(yuan)理是采用機械方(fang)法(fa)（更換變速(su)齒(chi)輪）來(lai)調速(su)。依靠電(dian)(dian)(dian)(dian)弧的自身調節作用來(lai)維持弧長(chang)(chang)相對穩定。當焊(han)接電(dian)(dian)(dian)(dian)弧受到外界干擾(rao)變長(chang)(chang)增加(jia)時(shi)，下降外特(te)性電(dian)(dian)(dian)(dian)源供(gong)給(gei)的焊(han)接電(dian)(dian)(dian)(dian)流減小，焊(han)絲熔(rong)化速(su)度減緩，電(dian)(dian)(dian)(dian)弧便會(hui)由(you)長(chang)(chang)變短，趨(qu)向給(gei)定值(zhi)；反之，電(dian)(dian)(dian)(dian)弧變短時(shi)，焊(han)接電(dian)(dian)(dian)(dian)流增大，焊(han)絲熔(rong)化加(jia)快，弧長(chang)(chang)又由(you)短變長(chang)(chang)，趨(qu)向給(gei)定值(zhi)。按這個工作原(yuan)理制造(zao)的等(deng)速(su)送絲埋弧焊(han)設備(bei)有MZ1-1000、MZ2-1500和MZ3-500等(deng)型(xing)號，焊(han)接電(dian)(dian)(dian)(dian)流可采用交、直電(dian)(dian)(dian)(dian)源。

2. 焊絲的(de)(de)送進速度按電(dian)弧電(dian)壓的(de)(de)高低自動(dong)均勻調(diao)節

  電(dian)(dian)弧(hu)(hu)電(dian)(dian)壓(ya)(ya)(ya)調(diao)(diao)節(jie)原理是(shi)利用電(dian)(dian)弧(hu)(hu)電(dian)(dian)壓(ya)(ya)(ya)作為反饋(kui)信(xin)號，經(jing)過控制調(diao)(diao)節(jie)系(xi)(xi)統改變(bian)送(song)絲速(su)度(du)(du)而(er)保持弧(hu)(hu)長(chang)(chang)相(xiang)對不變(bian)。當(dang)電(dian)(dian)弧(hu)(hu)受外界干擾變(bian)長(chang)(chang)，電(dian)(dian)弧(hu)(hu)電(dian)(dian)壓(ya)(ya)(ya)升(sheng)高時，控制調(diao)(diao)節(jie)系(xi)(xi)統接到電(dian)(dian)壓(ya)(ya)(ya)反饋(kui)信(xin)號后將(jiang)送(song)絲速(su)度(du)(du)調(diao)(diao)快，弧(hu)(hu)長(chang)(chang)由(you)長(chang)(chang)變(bian)短(duan)(duan)，趨向穩(wen)定(ding)值；當(dang)電(dian)(dian)弧(hu)(hu)長(chang)(chang)度(du)(du)變(bian)短(duan)(duan)，電(dian)(dian)弧(hu)(hu)電(dian)(dian)壓(ya)(ya)(ya)下降(jiang)時，將(jiang)送(song)絲速(su)度(du)(du)調(diao)(diao)慢，弧(hu)(hu)長(chang)(chang)增長(chang)(chang)趨向給定(ding)值。這種埋(mai)弧(hu)(hu)焊機的控制系(xi)(xi)統稍復雜，具(ju)體型(xing)號有MZ-1000和MZ-1-1000等型(xing)號。焊接電(dian)(dian)流(liu)可采用交(jiao)、直流(liu)電(dian)(dian)源。

  按工作需要，埋弧(hu)焊機常見的(de)構造形式有焊車式、懸掛式、機床(chuang)式、懸臂式和門架(jia)式等(deng)，如圖3-16所(suo)示。