SHOWALL HIGH VOLTAGE ROBOTICS
Figure 4 - Making a controllable ballast high voltage power supply on wheels
Figure 4 - Making a controllable ballast high voltage power supply on wheels

After some (careful) testing, it was found that the humongous transformer could indeed spit out almost 40 kilovolts, but as others have found, there is no way in hell you can just plug these power hungry beast directly into the AC outlet. Because the pole transformer has an unlimited appetite for current, the input side needs to be ballasted somehow as to not use more amperage than what is available at your outlet. In my case I was "limited" to "only" 240 volts at 200 amps...yikes! I tried several ballasting systems, including halogen lights, an old welder transformer, and even another coil, but the best system seemed to be a few stove elements set up in a series/parallel configuration.

Since I did not know if I could source 50 Kilovolt capacitors for this project, the series/parallel ballast switches allowed the output to be selected from approximately 20, 30, and 40 Kilovolts, in case I had to use a lesser supply voltage. The stove coils also worked well as ballast as they would become an almost dead short as they were cold, slowly passing current when the heated. This auto-ballasting worked perfectly in the charging circuit, allowing a faster charge without as many tripped breakers. The entire high voltage arrangement was fastened to a rolling cart made from a shopping cart. Now it was easy to roll the 500 pound, 40 Kilovolt power supply around my secret lab!



Figure 5 - The high voltage diode array to change AC to DC
Figure 5 - The high voltage diode array to change AC to DC

The output of the high voltage transformer was AC, but the capacitors required DC, so a very high voltage diode or rectifier was needed. A little scrounging on the Internet provided this 200 kilovolt diode array, which held up remarkably well to the abuse. I originally tried a 100 Kilovolt diode array from the same source, but it exploded after a few capacitor discharges. The diodes are the same ones as used in the HV section of a microwave oven, except that there are 16 of them in series. This diode array was connected to one lead of the transformer output, changing it from AC to chopped DC.

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