AN INEXPENSIVE HIGH-VOLTAGE AC SOURCE FOR LABORATORY USE

For testing high-voltage rectifiers and capacitor charging systems a power frequency source has been developed using readily available components in a series resonant circuit. The inductors are modified ignition transformers as used for oil or gas burners. The appropriate number of transformers is selected for the output required and tuned to resonate at 50 Hz with a separate bank of capacitors. Sustained voltages up to 100 kV RMS have been generated. Compared with single new transformers the cost is about 20% for 50 kV and 30% for 100 kV assemblies. The costs are those items which cannot readily be constructed in a nonspecialised laboratory workshop. The equipment is easily carried and assembled by one person. With rectifiers the system has been used successfully to supply up to 10 mA for charging capacitors to 50 kV. Extension to higher voltages is possible, the limit being set by the stray capacitance of the assembly.