在埋弧焊(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)絲的送進按預選定(ding)的速(su)度(du)等速(su)進入焊(han)接(jie)區

  工作原理是采用(yong)機械(xie)方(fang)法（更換變(bian)速(su)齒(chi)輪）來調速(su)。依靠電(dian)(dian)弧(hu)(hu)(hu)的自身調節作用(yong)來維持(chi)弧(hu)(hu)(hu)長(chang)相對(dui)穩定。當焊(han)接電(dian)(dian)弧(hu)(hu)(hu)受到外(wai)界干擾變(bian)長(chang)增加時，下降外(wai)特(te)性電(dian)(dian)源(yuan)供給(gei)的焊(han)接電(dian)(dian)流減小，焊(han)絲(si)熔化(hua)速(su)度減緩，電(dian)(dian)弧(hu)(hu)(hu)便會(hui)由(you)長(chang)變(bian)短，趨向(xiang)給(gei)定值(zhi)；反(fan)之，電(dian)(dian)弧(hu)(hu)(hu)變(bian)短時，焊(han)接電(dian)(dian)流增大，焊(han)絲(si)熔化(hua)加快，弧(hu)(hu)(hu)長(chang)又由(you)短變(bian)長(chang)，趨向(xiang)給(gei)定值(zhi)。按這個工作原理制造的等速(su)送(song)絲(si)埋(mai)弧(hu)(hu)(hu)焊(han)設備有MZ1-1000、MZ2-1500和MZ3-500等型號，焊(han)接電(dian)(dian)流可(ke)采用(yong)交、直電(dian)(dian)源(yuan)。

2. 焊絲的送進(jin)速度按電(dian)(dian)弧電(dian)(dian)壓的高(gao)低(di)自動均勻調節

  電(dian)(dian)(dian)弧(hu)(hu)(hu)(hu)電(dian)(dian)(dian)壓(ya)調(diao)節原理是利用(yong)電(dian)(dian)(dian)弧(hu)(hu)(hu)(hu)電(dian)(dian)(dian)壓(ya)作為反饋(kui)信(xin)號(hao)(hao)，經過(guo)控制調(diao)節系(xi)統(tong)改(gai)變(bian)(bian)(bian)(bian)送(song)絲(si)速(su)度而保持弧(hu)(hu)(hu)(hu)長(chang)(chang)相對不變(bian)(bian)(bian)(bian)。當電(dian)(dian)(dian)弧(hu)(hu)(hu)(hu)受(shou)外界干(gan)擾變(bian)(bian)(bian)(bian)長(chang)(chang)，電(dian)(dian)(dian)弧(hu)(hu)(hu)(hu)電(dian)(dian)(dian)壓(ya)升高時，控制調(diao)節系(xi)統(tong)接到電(dian)(dian)(dian)壓(ya)反饋(kui)信(xin)號(hao)(hao)后將送(song)絲(si)速(su)度調(diao)快，弧(hu)(hu)(hu)(hu)長(chang)(chang)由長(chang)(chang)變(bian)(bian)(bian)(bian)短，趨向穩(wen)定(ding)(ding)值(zhi)；當電(dian)(dian)(dian)弧(hu)(hu)(hu)(hu)長(chang)(chang)度變(bian)(bian)(bian)(bian)短，電(dian)(dian)(dian)弧(hu)(hu)(hu)(hu)電(dian)(dian)(dian)壓(ya)下降時，將送(song)絲(si)速(su)度調(diao)慢，弧(hu)(hu)(hu)(hu)長(chang)(chang)增長(chang)(chang)趨向給定(ding)(ding)值(zhi)。這(zhe)種埋弧(hu)(hu)(hu)(hu)焊機的控制系(xi)統(tong)稍復雜(za)，具體型號(hao)(hao)有MZ-1000和MZ-1-1000等型號(hao)(hao)。焊接電(dian)(dian)(dian)流可(ke)采用(yong)交、直流電(dian)(dian)(dian)源。

  按工作需要，埋弧焊(han)機常見(jian)的(de)構(gou)造(zao)形式(shi)有焊(han)車式(shi)、懸(xuan)掛(gua)式(shi)、機床式(shi)、懸(xuan)臂(bei)式(shi)和門架(jia)式(shi)等，如圖(tu)3-16所示。