ZX7-200焊機外殼實際上就(jiu)是(shi)(shi)具(ju)有(you)下降外(wai)特性(xing)的(de)(de)變(bian)壓器(qi)(qi)，將220V和380V交(jiao)流(liu)(liu)(liu)電(dian)(dian)(dian)(dian)(dian)(dian)變(bian)為低壓的(de)(de)直流(liu)(liu)(liu)電(dian)(dian)(dian)(dian)(dian)(dian)，電(dian)(dian)(dian)(dian)(dian)(dian)焊(han)(han)機一般按輸(shu)出(chu)(chu)(chu)電(dian)(dian)(dian)(dian)(dian)(dian)源種(zhong)(zhong)類可分為兩種(zhong)(zhong)，一種(zhong)(zhong)是(shi)(shi)交(jiao)流(liu)(liu)(liu)電(dian)(dian)(dian)(dian)(dian)(dian)源的(de)(de)；一種(zhong)(zhong)是(shi)(shi)直流(liu)(liu)(liu)電(dian)(dian)(dian)(dian)(dian)(dian)的(de)(de)。直流(liu)(liu)(liu)的(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)焊(han)(han)機可以說也(ye)是(shi)(shi)一個大功(gong)率的(de)(de)整流(liu)(liu)(liu)器(qi)(qi)，分正負，交(jiao)流(liu)(liu)(liu)電(dian)(dian)(dian)(dian)(dian)(dian)輸(shu)入時，經變(bian)壓器(qi)(qi)變(bian)壓后(hou)(hou)(hou)，再(zai)由整流(liu)(liu)(liu)器(qi)(qi)整流(liu)(liu)(liu)，然(ran)后(hou)(hou)(hou)輸(shu)出(chu)(chu)(chu)具(ju)有(you)下降外(wai)特性(xing)的(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)源，輸(shu)出(chu)(chu)(chu)端在接通和斷(duan)開時會產(chan)(chan)生(sheng)巨(ju)大的(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)壓變(bian)化(hua)，兩在瞬間短路時引(yin)(yin)燃電(dian)(dian)(dian)(dian)(dian)(dian)弧，利用產(chan)(chan)生(sheng)的(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)弧來熔化(hua)電(dian)(dian)(dian)(dian)(dian)(dian)焊(han)(han)條和焊(han)(han)材(cai)，冷(leng)卻后(hou)(hou)(hou)來達到使它們結合的(de)(de)目的(de)(de)。焊(han)(han)接變(bian)壓器(qi)(qi)有(you)自(zi)身的(de)(de)特點，外(wai)特性(xing)就(jiu)是(shi)(shi)在焊(han)(han)條引(yin)(yin)燃后(hou)(hou)(hou)電(dian)(dian)(dian)(dian)(dian)(dian)壓急劇下降的(de)(de)特性(xing)。

ZX7-200焊機外殼的主要(yao)部件(jian)(jian)是(shi)一(yi)個降(jiang)壓變(bian)壓器，次級線圈的兩端(duan)是(shi)被焊(han)接工(gong)件(jian)(jian)和焊(han)條(tiao)，工(gong)作時引燃電(dian)(dian)弧，在(zai)電(dian)(dian)弧的高溫中將焊(han)條(tiao)熔接于工(gong)件(jian)(jian)的縫隙(xi)中。由于電(dian)(dian)焊(han)變(bian)壓器的鐵(tie)芯有(you)(you)自身的特(te)點，因此具有(you)(you)電(dian)(dian)壓急劇下(xia)降(jiang)的特(te)性，即在(zai)焊(han)條(tiao)引燃后(hou)電(dian)(dian)壓下(xia)降(jiang)；在(zai)焊(han)條(tiao)被粘連短路 時，電(dian)(dian)壓   是(shi)急劇下(xia)降(jiang)。

在焊接(jie)(jie)(jie)操作(zuo)時(shi)，雖然電(dian)(dian)路中的電(dian)(dian)流(liu)處(chu)(chu)處(chu)(chu)相(xiang)等，但(dan)由于各(ge)處(chu)(chu)的電(dian)(dian)阻(zu) 不(bu)一樣，在不(bu)固(gu)定接(jie)(jie)(jie)觸(chu)處(chu)(chu)的電(dian)(dian)阻(zu)    大(這(zhe)個電(dian)(dian)阻(zu)叫接(jie)(jie)(jie)觸(chu)電(dian)(dian)阻(zu))，根據電(dian)(dian) 流(liu)的熱(re)效應定律(也叫焦爾定律)，即 Q=IR．t可(ke)知：在電(dian)(dian)流(liu)相(xiang)等時(shi)，則電(dian)(dian) 阻(zu)越大的部(bu)位(wei)發(fa)熱(re)越高(gao)，因此在焊 接(jie)(jie)(jie)時(shi)，焊條(tiao)的觸(chu)頭也就(jiu)是被(bei)接(jie)(jie)(jie)的金 屬體(ti)的接(jie)(jie)(jie)觸(chu)處(chu)(chu)的接(jie)(jie)(jie)觸(chu)電(dian)(dian)阻(zu)   大，則 在這(zhe)個部(bu)位(wei)產(chan)生的電(dian)(dian)熱(re)自(zi)然也就(jiu)    多，加之焊條(tiao)是熔點較低(di)的合金，自(zi)然容易熔化。熔化后(hou)的合金焊條(tiao)芯 粘合在被(bei)焊物(wu)體(ti)上，冷卻后(hou)便把焊 接(jie)(jie)(jie)對象(xiang)粘合在一塊。

焊機外殼使(shi)(shi)用(yong)電能源(yuan)，將電能瞬間轉換為(wei)熱能，電很(hen)(hen)普(pu)遍，ZX7-200焊(han)(han)機外殼電焊(han)(han)機適合在干(gan)燥的(de)(de)環境下(xia)工作，不(bu)需要(yao)太多要(yao)求(qiu)，因體(ti)積小巧(qiao)，操作簡單，使(shi)(shi)用(yong)方便，速度(du)較快，焊(han)(han)接(jie)(jie)后(hou)焊(han)(han)縫結實等(deng)優點廣泛用(yong)于(yu)各個，特別對要(yao)求(qiu)強度(du)很(hen)(hen)高(gao)的(de)(de)制件(jian)特實用(yong)，可(ke)以瞬間將同種(zhong)金屬材料(liao)（也可(ke)將異種(zhong)金屬連接(jie)(jie)，只是焊(han)(han)接(jie)(jie)方法不(bu)同）   性的(de)(de)連接(jie)(jie)，焊(han)(han)縫經熱處(chu)理后(hou)，與母(mu)材同等(deng)強度(du)，密封很(hen)(hen)好，這(zhe)給儲存氣體(ti)和(he)液體(ti)容器的(de)(de)制造解決了密封和(he)強度(du)的(de)(de)問題。