Power Supply:In common with many circuits, a Tesla coil requires a power supply, but not many need upwards of 6,000V! A commonly used source for such a high voltage is a neon sign transformer (NST). It takes in 240VAC (or your local equivalent) and transforms it up to around 6,000 to 15,000VAC. The transformer core is specifically designed to limit the output current to a maximum safe level, should the terminals become shorted. When I say safe I mean it will not cause the unit to overheat and catch fire but you can still be electrocutedthrough careless handling! My coil uses a 1KW NST, as shown below. It stands about 22cm tall and is quite heavy (approx 20KG). It came from the one local sign shop which catered for neon signs... |
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| * After frying the NST during a max performance run, I ordered a replacement unit directly from 'Tunewell'. They were very helpfull and happy to take one off orders from members of the public. I did not mention the use I was putting it to; no reason to alarm them!
1kW was the largest NST I could find in the UK, and 10kV is the highest voltage rating available in this country. If you wish to run a coil at higher power levels, it is possible to parallel connect identical NSTs together to increase the available current while keeping the voltage constant. For really big coils, running at power levels over a few kW, a suitable transformer is a 'Pole Pig', or more correctly, a line transformer. These are used by the power companies to step down high voltage feeds (11kV) to 240V. They can be wired in reverse, to produce the high voltage you need but they require extra current limmiting circuitry before they are usable. These are large, heavy items (200KG), NOT for beginners!
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Here is my newly aquired high voltage transformer. It is supposed to be a 'Plate Transformer', used to provide the supply for large radio valves, I believe.
Input voltage is 200VAC and output is 14,400VAC@200mA. |
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