Equivalent circuit for high-voltage partial-core resonant transformers

An equivalent circuit model for the partial-core resonant transformer is presented. A model which omits core losses is first introduced and is verified on a sample air-core resonant transformer. Partial-cores are then introduced into the transformer and the resonant characteristics are re-measured. The model is modified to account for the core losses and then verified against the measured data. Comparisons and transformations between the model and the Steinmetz ´exact´ transformer equivalent circuit are given. A procedure for measuring the equivalent circuit inductances is described and then used to investigate the inductance variation with core displacement characteristics of the sample transformer in both axial-offset and centre-gap arrangements. In a capacitive load test the sample transformer was linear to a significantly higher voltage when using the centre-gap arrangement.