DC welding transformers
For all kinds of intermediate frequency, power frequency
resistance welding machine.Such as automobile welding clamp,
seam welding machine, mesh welding machine and so on.
Medium-frequency (MF) transformers are a result of recent advances in resistance welding technology.
They arepowered by a transistor inverter, supplying square wave AC 500 V @ 1000 Hz which is converted
by the MF transformer to a low voltage high current AC. This low voltage AC current is rectified to DC by
a diode block built into the transformer.The higher operating frequency of an MF system allows efficient
energy conversion using a smaller and lighter transformer.Other benefits with MF transformers used in
portable and robotic welding guns are:The reactance of the welding loop only limits the upslope and down
slope of the welding current, while the peak welding current in limited only by the welding loop’s resistance.
The net result is again smaller transformer, especially when welding with large throat, high-impedance guns.
MF welding is less demanding on the plant power system. The MF inverter draws balanced line current from
all 3 phases and operates at a high power factor (0.9).With MF transformers the peak welding current almost
equals its RMS value, which helps to obtain quality welds with no splash and constantstrength even at lower
pressure.The high frequency permits much faster – 1000 times per second - process control, which again results
in better weld quality.