Medium frequency dc transformer is also called MFDC transformer.It is made of transformer coil and rectifier device.The medium frequency dc inverter resistance welding transformer working frequency is 1000Hz with low voltage high current output.Compare with ordinary power frequency transformer,Medium frequency transformer have more advantages.Its secondary current is dc current.Improved solder joint quality.Small size and light weight,electrode life is longer,Excellent performance in welding materials such as aluminum and galvanized metal.Medium frequency DC resistance welding system are composed of medium frequency inverter(MFDC inverter),MFDC transformer,workpiece etc.Our resistance welding transformers are widely used on spot welding machine,seam welding machine,butt welding machine etc.
Principle of Medium Frequency Welding Transformer:
Firstly,three phase AC is rectified to DC by rectifier.and then inverter the DC into a new AC through a bridge circuit composed of IGBTs.Input to Mid-frequency welding transformer,the secondary of the transformer is equipped with a rectifier diode to convert the welding current to DC.Since the output current of MF transformer is DC,it is easier to control the welding process and complete welding more rapidly and stably.The welding frequency is 1000Hz,Therefore,its current regulation is faster and more accurate,relative to 50Hz power supply.
Advantage of Medium Frequency Welding Machine:
- Three phase power supply system improves the efficiency of power usage.High power factor is close to 1;
- The current of secondary welding circuit is DC.It greatly reduces the impact on welding current from inductive reactance in the secondary ciruit caused by different immersion depths in the work piece.The welding current is continuous DC,stabilized and free of zero crossing.The heat is concentrated.Therefore,the welding time can be shortened to save a significant of energy;
- The volume and weight of welding transformer are greatly reduced;
- The welding machine is not affected by maximum value of AC and weld spatter is small,so the service life of electrodes are also extended;
- It can be used to weld aluminum and galvanized metal.Welding result is very good;
- It is especially suitable for welding three-layer alloy sheets and thin materials and can meet the requirements of precision welding.
MFDC Welding Transformer Technical Specifications:
| Model | MF130KVA | MF170KVA | MF220KVA | MF220KVA | MF250KVA | MF500KVA | MF600KVA |
|---|---|---|---|---|---|---|---|
| Power | 130KVA | 170KVA | 220KVA | 310KVA | 250KVA | 500KVA | 650KVA |
| Primary Voltage | 500V,1000Hz | 500V,1000Hz | 500V,1000Hz | 500V,1000Hz | 500V,1000Hz | 500V,1000Hz | 500V,1000Hz |
| No-load Secondary Voltage | 9.2V | 9.2V | 9.2V | 13V | 13V | 13V | 10.5V-13V |
| ED=20% | 15KA,135KVA | 19KA,170KVA | 24KA,220KVA | 24KA,310KVA | 19KA,240KVA | 40KA,520KVA | 45KA,470-580KVA |
| ED=50% | 9.5KA,85KVA | 12KA,110KVA | 14KA,120KVA | 14KA,180KVA | 12.5KA,160KVA | 32KA,410KVA | 36KA,380-470KVA |
| ED=100% | 6.5KA,60KVA | 8.5KA,80KVA | 10KA,92KVA | 10KA,130KVA | 8.5KA,100KVA | 20KA,260KVA | 24KA,250-310KVA |
| Insulation Class | F | F | F | F | F | F | F |
| Turns Ratio | 55:1 | 55:1 | 55:1 | 38:1 | 38:1 | 38:1 | 38-48 |
| Maximum Short Circuit Current | 26KA | 40KA | 40KA | 40KA | 40KA | 60KA | 70KA |
| Cooling Water | ≥8L/min,<30degree | ≥8L/min,<30degree | ≥8L/min,<30degree | ≥8L/min,<30degree | ≥8L/min,<30degree | ≥8L/min,<30degree | ≥8L/min*4,<30degree |
| Diode type | ZE13500A *2 | 13500A*2 | 13500A*4 | 12000A*2 | 12000A*2 | 12000A*4 | 12000A*8 |
| Weight | 15KG | 20KG | 25KG | 24KG | 20KG | 60KG | 66KG |
| Standard | GB15575-2008 | GB15575-2008 | GB15575-2008 | GB15575-2008 | GB15575-2008 | GB15575-2008 | GB15575-2008 |
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