Analysis of ohmic losses in Tesla transformers utilizing the open magnetic-core

For typical Tesla transformers with open magnetic-core, a novel coaxial design of the primary side using a mechanically controlled spark gap is introduced to obtain a more compact configuration. The primary winding has several alternative ports to vary the current distribution by changing the position of the capacitor component, and the entire primary circuit is built inside the outer cylinder. For this new primary configuration, we estimate the series parameters and ohmic losses: Polypropylene film capacitors and combined metallized film capacitors are used in the verification tests, and the former capacitor exhibits a lower parasitic resistance below 10 mΩ. The ohmic losses caused by the windings and spark gap are also considered. The results of the experiments show that the voltage gain has an 8.2% drop when the parasitic resistance of C1 increased from 10 mΩ to 24 mΩ, and we deduce that the contact resistance of this primary structure can be limited to below 10 mΩ according to the circuit analysis results and the verification test.