在埋(mai)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(song)進按預選(xuan)定的速度等(deng)速進入焊接區

  工(gong)(gong)作原(yuan)理是采用機(ji)械方法（更換變(bian)速(su)(su)齒輪）來(lai)(lai)調速(su)(su)。依靠電(dian)(dian)弧(hu)的(de)自身調節作用來(lai)(lai)維持弧(hu)長(chang)(chang)相對(dui)穩定(ding)。當焊(han)(han)接(jie)電(dian)(dian)弧(hu)受到外界干(gan)擾(rao)變(bian)長(chang)(chang)增加(jia)時，下(xia)降外特性電(dian)(dian)源供給(gei)的(de)焊(han)(han)接(jie)電(dian)(dian)流(liu)減小(xiao)，焊(han)(han)絲熔(rong)化(hua)速(su)(su)度減緩，電(dian)(dian)弧(hu)便會由長(chang)(chang)變(bian)短(duan)，趨向(xiang)給(gei)定(ding)值；反之，電(dian)(dian)弧(hu)變(bian)短(duan)時，焊(han)(han)接(jie)電(dian)(dian)流(liu)增大(da)，焊(han)(han)絲熔(rong)化(hua)加(jia)快，弧(hu)長(chang)(chang)又(you)由短(duan)變(bian)長(chang)(chang)，趨向(xiang)給(gei)定(ding)值。按(an)這個工(gong)(gong)作原(yuan)理制造的(de)等速(su)(su)送絲埋(mai)弧(hu)焊(han)(han)設備有MZ1-1000、MZ2-1500和MZ3-500等型號，焊(han)(han)接(jie)電(dian)(dian)流(liu)可(ke)采用交、直電(dian)(dian)源。

2. 焊絲的(de)送進速度按電(dian)(dian)弧電(dian)(dian)壓的(de)高(gao)低(di)自動均(jun)勻調節

  電(dian)(dian)弧(hu)(hu)電(dian)(dian)壓(ya)調(diao)(diao)(diao)節原理是利用電(dian)(dian)弧(hu)(hu)電(dian)(dian)壓(ya)作為反饋信號，經過(guo)控(kong)(kong)制調(diao)(diao)(diao)節系(xi)統改變(bian)送(song)(song)(song)絲(si)速(su)(su)度(du)而(er)保持弧(hu)(hu)長(chang)相對不變(bian)。當(dang)電(dian)(dian)弧(hu)(hu)受外界干(gan)擾變(bian)長(chang)，電(dian)(dian)弧(hu)(hu)電(dian)(dian)壓(ya)升高時，控(kong)(kong)制調(diao)(diao)(diao)節系(xi)統接到電(dian)(dian)壓(ya)反饋信號后將(jiang)送(song)(song)(song)絲(si)速(su)(su)度(du)調(diao)(diao)(diao)快，弧(hu)(hu)長(chang)由長(chang)變(bian)短，趨向穩定值；當(dang)電(dian)(dian)弧(hu)(hu)長(chang)度(du)變(bian)短，電(dian)(dian)弧(hu)(hu)電(dian)(dian)壓(ya)下(xia)降時，將(jiang)送(song)(song)(song)絲(si)速(su)(su)度(du)調(diao)(diao)(diao)慢(man)，弧(hu)(hu)長(chang)增長(chang)趨向給定值。這(zhe)種埋弧(hu)(hu)焊(han)機的控(kong)(kong)制系(xi)統稍(shao)復雜，具體(ti)型號有MZ-1000和MZ-1-1000等型號。焊(han)接電(dian)(dian)流(liu)可(ke)采用交、直流(liu)電(dian)(dian)源。

  按工作(zuo)需要，埋弧焊機(ji)常(chang)見(jian)的構造形式(shi)有焊車式(shi)、懸掛式(shi)、機(ji)床(chuang)式(shi)、懸臂式(shi)和門架式(shi)等，如圖3-16所示。