Design, manufacturing, and testing of 0.35/25 kV, 20 kHz transformers for particle accelerators.

This article focuses on the design, manufacturing, and testing of a high voltage, high frequency (HVHF) transformer unit developed to power a Cockcroft–Walton voltage multiplier for a particle accelerator power supply at the Institute for Plasma Research (IPR), India. The transformer unit, rated at 70 kV·A with specifications of 25 kV secondary voltage and 20 kHz operating frequency, consists of two amorphous core transformers connected in a center-tap configuration and immersed in oil for insulation and cooling. The design process involved detailed magnetic, electrical, and thermal analyses, including finite element method (FEM) simulations to optimize core selection, winding arrangements, insulation, and to predict parasitic effects such as eddy currents, stray capacitances, and dielectric losses. The manufactured transformers underwent comprehensive testing—measuring parameters like winding resistance, inductance, capacitance, insulation resistance, and dielectric strength—and were successfully integrated with the Cockcroft–Walton multiplier, demonstrating stable operation with efficiency exceeding 95% and delivering up to 316 kV DC output under load conditions.