This patent protect the developed advanced control system for spot welding transformer, which is based on measurement of welding current and flux density in the transformer iron core. The welding current at the full–wave rectifier output is normally controlled by the pulse width modulated primary voltage of the transformer supplied by the input converter. The unequal ohmic resistances of the two transformer’s secondary circuits and the different characteristics of the diodes of output rectifier certainly lead to the magnetic saturation which, consequently, causes the unwanted spikes in the transformer’s primary current and over–current protection switch–off. This disadvantage of classical spot welding systems is completely eliminated by the protected advanced hysteresis controller (AHC), which keeps transformer iron core saturation within prescribed bounds regardless of how unequal the ohmic resistances and diode characteristics in the transformer’s secondary circuits are. This is achieved by a combined closed–loop control of the welding current and closed–loop control of the iron core saturation level. The proposed AHC assures a very short rise time of the welding current and the best possible utilization of the transformer iron core.
F.32 International patent
COBISS.SI-ID: 15194902This patent protect special design of secondary coils of a middle–frequency resistance spot welding transformers, which are water cooled. Protected is also special distribution of water cooled secondary coils and primary coils, which are also efficiently cooled by water in indirect way. This solution is already implemented in production of such systems in Slovene company Indramat.
F.32 International patent
COBISS.SI-ID: 15194134The spot welding system consists of an input converter, welding transformer, and a full–wave rectifier mounted at the transformer secondary. Two diodes of full–wave output rectifier are placed directly at the welding transformer housing and are also water cooled. The new system of placement of diodes is protected by this patent, because it is much more simple and less expensive than usually. This solution is already implemented in production in Slovene company Indramat.
F.32 International patent
COBISS.SI-ID: 15194390