Influence of the leakage flux of the transformer on the welding current of high frequency resistance spot welding systems

High frequency resistance spot welding systems are considered. They have full-wave centre tapped output rectifiers and three-winding transformer. The leakage flux of three-winding transformer including in the systems, influences on the welding current. For calculation of welding current the three-winding transformer is replaced by two two-winding ones. The mutual influence of the magnetic leakage fields of these two-winding transformers on welding current is investigated. It is shown that welding current depends both on the modulus and the sign of the coupling factor of the magnetic leakage fields of these two-winding transformers. The paper presents the dependences of the welding current from the coupling factor. They can be used for creation of economical transformers.