Resistance welding systems which are based on medium-frequency inverters are recently gaining in importance. All inverters have the principal design in common: first, the 3-phase input current is rectified and, in the downstream inverter unit, chopped by means of power semiconductors (IGBT) into higher-frequency alternating current of 1 kHz. This alternating current is then transformed by the welding transformer into quantities which are suitable for welding and, subsequently, rectified. Thus, direct current (DC) is applied at the welding point.
The price is higher than that of alternating current systems, but the multitude of advantages of the MFDC systems will certainly make up for the higher costs:
These high-speed controllable MFDC power sources are, in sheet welding, also suitable for the application of the adaptive MASTER control method. Based on a reference welding, MASTER adapts the welding parameters optimally, also during disturbing influences such as shunts, sheet bulging, etc.
Depending on the necessary welding power and the intended interface equipment, the medium frequency systems of the SPATZ, AutoSPATZ and ServoSPATZ families are available.
| Inverter | Welding Current |
|---|---|
| SPATZM300 | up to 18 kA |
| AutoSPATZM600L | up to 30 kA |
| AutoSPATZM1600 | up to 65 kA |
| AutoSPATZM2400 | up to 100 kA |
| SilverSPATZM600LL SilverSPATZM600LW |
up to 30 kA |
| SilverSPATZM800LL SilverSPATZM800LW |
up to 30 kA |
| ServoSPATZM600LL ServoSPATZM600LW ServoSPATZM800LL ServoSPATZM800LW |
up to 30 kA |
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