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(de)送進(jin)按(an)預選(xuan)定的(de)速度等速進(jin)入(ru)焊接區(qu)

  工(gong)作(zuo)(zuo)原理是采用(yong)機(ji)械方法（更換變(bian)速(su)(su)齒輪）來(lai)(lai)調速(su)(su)。依靠(kao)電(dian)(dian)弧(hu)的(de)自身(shen)調節作(zuo)(zuo)用(yong)來(lai)(lai)維(wei)持弧(hu)長(chang)(chang)相對穩定。當焊(han)(han)接(jie)電(dian)(dian)弧(hu)受到外(wai)(wai)界干(gan)擾變(bian)長(chang)(chang)增(zeng)加時，下降外(wai)(wai)特性電(dian)(dian)源(yuan)供給的(de)焊(han)(han)接(jie)電(dian)(dian)流(liu)減(jian)小，焊(han)(han)絲(si)熔化速(su)(su)度(du)減(jian)緩(huan)，電(dian)(dian)弧(hu)便(bian)會由長(chang)(chang)變(bian)短，趨向給定值；反(fan)之，電(dian)(dian)弧(hu)變(bian)短時，焊(han)(han)接(jie)電(dian)(dian)流(liu)增(zeng)大，焊(han)(han)絲(si)熔化加快，弧(hu)長(chang)(chang)又由短變(bian)長(chang)(chang)，趨向給定值。按(an)這個(ge)工(gong)作(zuo)(zuo)原理制造的(de)等(deng)速(su)(su)送絲(si)埋弧(hu)焊(han)(han)設備有MZ1-1000、MZ2-1500和MZ3-500等(deng)型號，焊(han)(han)接(jie)電(dian)(dian)流(liu)可采用(yong)交、直電(dian)(dian)源(yuan)。

2. 焊絲的送進速(su)度按電弧電壓的高低自(zi)動均(jun)勻調(diao)節

  電(dian)(dian)弧(hu)電(dian)(dian)壓調(diao)節原理是利用(yong)電(dian)(dian)弧(hu)電(dian)(dian)壓作為(wei)反饋信號(hao)，經(jing)過控(kong)制調(diao)節系統(tong)改變(bian)(bian)(bian)送(song)(song)絲(si)速(su)度而保持弧(hu)長(chang)(chang)(chang)相對不(bu)變(bian)(bian)(bian)。當(dang)電(dian)(dian)弧(hu)受(shou)外界干(gan)擾變(bian)(bian)(bian)長(chang)(chang)(chang)，電(dian)(dian)弧(hu)電(dian)(dian)壓升高時(shi)，控(kong)制調(diao)節系統(tong)接到電(dian)(dian)壓反饋信號(hao)后將送(song)(song)絲(si)速(su)度調(diao)快，弧(hu)長(chang)(chang)(chang)由長(chang)(chang)(chang)變(bian)(bian)(bian)短(duan)，趨向穩定值；當(dang)電(dian)(dian)弧(hu)長(chang)(chang)(chang)度變(bian)(bian)(bian)短(duan)，電(dian)(dian)弧(hu)電(dian)(dian)壓下降時(shi)，將送(song)(song)絲(si)速(su)度調(diao)慢(man)，弧(hu)長(chang)(chang)(chang)增長(chang)(chang)(chang)趨向給定值。這種埋弧(hu)焊機的控(kong)制系統(tong)稍復雜，具體型號(hao)有MZ-1000和MZ-1-1000等型號(hao)。焊接電(dian)(dian)流(liu)可采用(yong)交、直流(liu)電(dian)(dian)源。

  按工(gong)作需要，埋弧焊機(ji)常見的(de)構造形式(shi)(shi)有焊車式(shi)(shi)、懸掛式(shi)(shi)、機(ji)床式(shi)(shi)、懸臂式(shi)(shi)和(he)門架式(shi)(shi)等，如(ru)圖3-16所示。