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(han)絲的(de)(de)送進(jin)按(an)預選(xuan)定的(de)(de)速度等(deng)速進(jin)入(ru)焊(han)接區

  工作(zuo)原理(li)是(shi)采(cai)用機械方(fang)法（更換變(bian)速齒(chi)輪）來調速。依靠電(dian)(dian)(dian)弧(hu)(hu)的自身(shen)調節作(zuo)用來維持(chi)弧(hu)(hu)長(chang)(chang)相對穩(wen)定(ding)(ding)。當焊接電(dian)(dian)(dian)弧(hu)(hu)受到外(wai)界干擾變(bian)長(chang)(chang)增(zeng)(zeng)加時，下降外(wai)特性電(dian)(dian)(dian)源供(gong)給(gei)的焊接電(dian)(dian)(dian)流減小，焊絲(si)熔化(hua)速度減緩(huan)，電(dian)(dian)(dian)弧(hu)(hu)便會由長(chang)(chang)變(bian)短，趨(qu)向給(gei)定(ding)(ding)值(zhi)；反(fan)之，電(dian)(dian)(dian)弧(hu)(hu)變(bian)短時，焊接電(dian)(dian)(dian)流增(zeng)(zeng)大，焊絲(si)熔化(hua)加快，弧(hu)(hu)長(chang)(chang)又由短變(bian)長(chang)(chang)，趨(qu)向給(gei)定(ding)(ding)值(zhi)。按這(zhe)個工作(zuo)原理(li)制造的等(deng)速送(song)絲(si)埋弧(hu)(hu)焊設備有(you)MZ1-1000、MZ2-1500和MZ3-500等(deng)型(xing)號，焊接電(dian)(dian)(dian)流可采(cai)用交、直電(dian)(dian)(dian)源。

2. 焊絲的送(song)進速度按(an)電(dian)弧電(dian)壓的高低自動均勻調節

  電(dian)(dian)(dian)(dian)(dian)弧(hu)(hu)(hu)(hu)電(dian)(dian)(dian)(dian)(dian)壓調節原理是利用電(dian)(dian)(dian)(dian)(dian)弧(hu)(hu)(hu)(hu)電(dian)(dian)(dian)(dian)(dian)壓作為反(fan)饋(kui)信號，經過控制調節系統改變(bian)送(song)(song)絲(si)速度而保持弧(hu)(hu)(hu)(hu)長相對不變(bian)。當電(dian)(dian)(dian)(dian)(dian)弧(hu)(hu)(hu)(hu)受外界干擾變(bian)長，電(dian)(dian)(dian)(dian)(dian)弧(hu)(hu)(hu)(hu)電(dian)(dian)(dian)(dian)(dian)壓升高時(shi)，控制調節系統接(jie)到電(dian)(dian)(dian)(dian)(dian)壓反(fan)饋(kui)信號后將送(song)(song)絲(si)速度調快，弧(hu)(hu)(hu)(hu)長由長變(bian)短，趨(qu)向穩定值；當電(dian)(dian)(dian)(dian)(dian)弧(hu)(hu)(hu)(hu)長度變(bian)短，電(dian)(dian)(dian)(dian)(dian)弧(hu)(hu)(hu)(hu)電(dian)(dian)(dian)(dian)(dian)壓下降時(shi)，將送(song)(song)絲(si)速度調慢，弧(hu)(hu)(hu)(hu)長增長趨(qu)向給定值。這種埋弧(hu)(hu)(hu)(hu)焊(han)機的控制系統稍復雜，具體型號有(you)MZ-1000和MZ-1-1000等型號。焊(han)接(jie)電(dian)(dian)(dian)(dian)(dian)流(liu)可采用交、直(zhi)流(liu)電(dian)(dian)(dian)(dian)(dian)源(yuan)。

  按工作(zuo)需要，埋弧焊機常見(jian)的構造形式有焊車式、懸(xuan)掛(gua)式、機床式、懸(xuan)臂(bei)式和門架式等，如(ru)圖3-16所示。