在埋弧(hu)焊(han)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)的送進按預選定的速度等速進入焊(han)接(jie)區

  工(gong)作原理是(shi)采(cai)用機械方法（更換(huan)變(bian)(bian)速齒輪）來調速。依(yi)靠電(dian)弧(hu)的自身調節(jie)作用來維持弧(hu)長相對穩定。當焊(han)(han)接電(dian)弧(hu)受到外(wai)界(jie)干擾變(bian)(bian)長增(zeng)加時，下降外(wai)特性電(dian)源供給的焊(han)(han)接電(dian)流減(jian)小(xiao)，焊(han)(han)絲熔化(hua)速度減(jian)緩，電(dian)弧(hu)便會由(you)長變(bian)(bian)短(duan)(duan)，趨(qu)向給定值；反(fan)之，電(dian)弧(hu)變(bian)(bian)短(duan)(duan)時，焊(han)(han)接電(dian)流增(zeng)大，焊(han)(han)絲熔化(hua)加快(kuai)，弧(hu)長又由(you)短(duan)(duan)變(bian)(bian)長，趨(qu)向給定值。按(an)這個工(gong)作原理制造的等速送(song)絲埋弧(hu)焊(han)(han)設備(bei)有MZ1-1000、MZ2-1500和MZ3-500等型號，焊(han)(han)接電(dian)流可采(cai)用交、直電(dian)源。

2. 焊絲(si)的送進速度按電(dian)弧(hu)電(dian)壓的高(gao)低(di)自動均勻調節

  電(dian)(dian)(dian)(dian)(dian)弧(hu)(hu)電(dian)(dian)(dian)(dian)(dian)壓(ya)調(diao)(diao)(diao)節(jie)原理是利(li)用電(dian)(dian)(dian)(dian)(dian)弧(hu)(hu)電(dian)(dian)(dian)(dian)(dian)壓(ya)作為反饋(kui)信號，經(jing)過控(kong)(kong)(kong)制(zhi)調(diao)(diao)(diao)節(jie)系統改變(bian)送絲(si)速(su)度而保持弧(hu)(hu)長(chang)相對不變(bian)。當(dang)電(dian)(dian)(dian)(dian)(dian)弧(hu)(hu)受(shou)外(wai)界干擾變(bian)長(chang)，電(dian)(dian)(dian)(dian)(dian)弧(hu)(hu)電(dian)(dian)(dian)(dian)(dian)壓(ya)升高時(shi)(shi)，控(kong)(kong)(kong)制(zhi)調(diao)(diao)(diao)節(jie)系統接(jie)到電(dian)(dian)(dian)(dian)(dian)壓(ya)反饋(kui)信號后將(jiang)送絲(si)速(su)度調(diao)(diao)(diao)快，弧(hu)(hu)長(chang)由長(chang)變(bian)短(duan)，趨向(xiang)穩定值(zhi)；當(dang)電(dian)(dian)(dian)(dian)(dian)弧(hu)(hu)長(chang)度變(bian)短(duan)，電(dian)(dian)(dian)(dian)(dian)弧(hu)(hu)電(dian)(dian)(dian)(dian)(dian)壓(ya)下(xia)降時(shi)(shi)，將(jiang)送絲(si)速(su)度調(diao)(diao)(diao)慢，弧(hu)(hu)長(chang)增長(chang)趨向(xiang)給定值(zhi)。這(zhe)種埋弧(hu)(hu)焊機的控(kong)(kong)(kong)制(zhi)系統稍復雜，具體型號有MZ-1000和MZ-1-1000等型號。焊接(jie)電(dian)(dian)(dian)(dian)(dian)流(liu)可采用交、直(zhi)流(liu)電(dian)(dian)(dian)(dian)(dian)源。

  按工(gong)作需要，埋弧焊(han)機常見(jian)的構(gou)造(zao)形式(shi)有焊(han)車式(shi)、懸掛(gua)式(shi)、機床式(shi)、懸臂式(shi)和(he)門架式(shi)等(deng)，如圖(tu)3-16所示(shi)。