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(si)的(de)送(song)進按預選定的(de)速度等速進入焊(han)接區(qu)

  工(gong)作(zuo)原理是(shi)采用(yong)(yong)機械方法（更(geng)換(huan)變(bian)(bian)(bian)(bian)(bian)速(su)齒輪）來調速(su)。依靠電弧(hu)的(de)(de)自(zi)身調節作(zuo)用(yong)(yong)來維(wei)持弧(hu)長相對穩(wen)定。當焊(han)接(jie)(jie)電弧(hu)受到(dao)外界干擾(rao)變(bian)(bian)(bian)(bian)(bian)長增(zeng)(zeng)加時，下降外特(te)性電源供(gong)給(gei)的(de)(de)焊(han)接(jie)(jie)電流減小，焊(han)絲熔化(hua)速(su)度減緩，電弧(hu)便(bian)會由(you)(you)長變(bian)(bian)(bian)(bian)(bian)短，趨向(xiang)給(gei)定值；反(fan)之(zhi)，電弧(hu)變(bian)(bian)(bian)(bian)(bian)短時，焊(han)接(jie)(jie)電流增(zeng)(zeng)大，焊(han)絲熔化(hua)加快，弧(hu)長又(you)由(you)(you)短變(bian)(bian)(bian)(bian)(bian)長，趨向(xiang)給(gei)定值。按(an)這個工(gong)作(zuo)原理制造的(de)(de)等速(su)送絲埋(mai)弧(hu)焊(han)設備(bei)有MZ1-1000、MZ2-1500和MZ3-500等型號，焊(han)接(jie)(jie)電流可(ke)采用(yong)(yong)交、直電源。

2. 焊絲的送進速度(du)按電弧電壓的高(gao)低(di)自動均勻調節

  電(dian)(dian)(dian)(dian)弧(hu)電(dian)(dian)(dian)(dian)壓(ya)調(diao)節原理是利用電(dian)(dian)(dian)(dian)弧(hu)電(dian)(dian)(dian)(dian)壓(ya)作為反(fan)饋信號，經過控制(zhi)(zhi)調(diao)節系(xi)(xi)(xi)統(tong)改變送(song)(song)絲(si)(si)速度(du)而保持弧(hu)長(chang)相對(dui)不(bu)變。當電(dian)(dian)(dian)(dian)弧(hu)受外界(jie)干擾變長(chang)，電(dian)(dian)(dian)(dian)弧(hu)電(dian)(dian)(dian)(dian)壓(ya)升高(gao)時，控制(zhi)(zhi)調(diao)節系(xi)(xi)(xi)統(tong)接到電(dian)(dian)(dian)(dian)壓(ya)反(fan)饋信號后(hou)將送(song)(song)絲(si)(si)速度(du)調(diao)快，弧(hu)長(chang)由長(chang)變短(duan)，趨(qu)向穩定值(zhi)；當電(dian)(dian)(dian)(dian)弧(hu)長(chang)度(du)變短(duan)，電(dian)(dian)(dian)(dian)弧(hu)電(dian)(dian)(dian)(dian)壓(ya)下降時，將送(song)(song)絲(si)(si)速度(du)調(diao)慢，弧(hu)長(chang)增長(chang)趨(qu)向給定值(zhi)。這種(zhong)埋弧(hu)焊(han)(han)機的控制(zhi)(zhi)系(xi)(xi)(xi)統(tong)稍(shao)復雜，具體(ti)型(xing)(xing)號有MZ-1000和MZ-1-1000等型(xing)(xing)號。焊(han)(han)接電(dian)(dian)(dian)(dian)流(liu)可采用交、直(zhi)流(liu)電(dian)(dian)(dian)(dian)源。

  按工作需要，埋弧(hu)焊機常見的構造(zao)形式(shi)有焊車式(shi)、懸掛式(shi)、機床式(shi)、懸臂式(shi)和門架(jia)式(shi)等，如(ru)圖3-16所示。