包头钢铁学校设计、制造的小型电焊机(图4),系无电抗器式的三用电焊机,可焊2～5毫米直径的电焊条(电流70～180安,空载电压50～65伏,工作电压20～30伏)、可作电瓶铅焊的电源(10伏,80安)以及作为汽车发动机打火用(12伏,80安以上)。容量7～12仟伏安,原级电压380/220V,单相,重量25公斤。经三年多的使用,效果良好。 Baotou Iron and Steel School design, manufacture of small welding machine (Figure 4), the reactor-free three-use welding machine, welding 2 to 5 mm diameter welding electrodes (current 70 ~ 180 amps, no-load voltage 50 ~ 65 volts , Working voltage 20 ~ 30V), can be used for battery lead welding power supply (10V, 80A), and as a car engine ignition (12V, 80A and above). Capacity of 7 to 12 thousand volt-ampere, the primary voltage 380 / 220V, single-phase, weight 25 kg. After three years of use, the effect is good.