Tesla Coil

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The Tesla Coil.

All over the web, geeks are devoting their lives to building Tesla coils. It's no big deal. We built one in a day out of crap and it works as good as anything on the other sites. You can build them as big as you like, it just depends if you have a life......

Number of calculations done: 0

Time spend tuning: 0

Number of smug photos of builder: 0

Oscilloscopes used: 0

Tea consumed: 8 mugs

Dangerous shit alert!

Warning! The voltages and currents operating in the equipment shown on this page are absolutely lethal. Dr Bellend is a bodger with many years experience and does not accept responsibility for any loss or injury incurred as a result of attempts to replicate this device.

Ingredients: 4 microwave oven transformers, (from old microwaves please), capacitors (Maplin or RS), car brake pipe (Dirty Barry's car parts), various plumbing bits (B&Q), transformer wire (Maplin or RS), Variac or old convector heater for ballast. An fast motor from a Hoover/Strimmer and lots of assorted junk.

Introduction.

At the turn of the century Nikola Tesla invented a high frequency air-cored transformer with the aim of transmitting electricity without wires. He carried out many successful experiments, but it never came to fruition. Since then geeks have built small coils based on neon sign transformers. However the web changed all that, and fellow geeks could share the results of their experiments and pretty soon sites were showing coils ablaze in a mass of sparks.

Building a Tesla Coil...

Power supply. 4 X microwave oven transformers wired in series-parallel to give about 8Kv at approx 0.5 Amp full power. These must be current limited so they are supplied from a variac. The 2 outer transformers are stressed to 8X their normal voltage between core and primary so the whole thing is dumped in transformer oil. Don't use engine oil, we tested some and it was rubbish (water would probably have been better).
Capacitor. 10 X 0.033uF 2Kv in series to give 33nF at 20Kv. I bunged these in a piece of waste pipe.
Spark gap. My first attempt exploded on 10,000 rpm test and stuck in the garage ceiling. Oops. Built a stronger one out of some Plexiglass I scrounged. Motor is from a Strimmer. Balancing is a mile out so it sits on a few layers of carpet underlay for vibration control.



Supply. dedicated switch fuse that doesn't come through our RCD. Coil runs with a 20A breaker ok without tripping it.
The variac. Fitted with a beacon to remind me not to fry myself on the 8Kv power supply.
Early amateur coil from the 80's. This was before the internet came along though.
First test of the latest coil running on a small power supply.
Same coil at high power trying to set my garage on fire. Tesla coil. Done. What's for tea?
Tesla's magnifying coil from 1899. A scientist and gentleman, not a pen-collecting geek university failure.

Circuit diagram click here: images\tesla diag.pdf

Video of coil in action on U Tube: http://www.youtube.com/watch?v=EaX_hyyG35o

Climbing Arc, (as seen in Frankenstein's Lab).

Ingredients: 1 High voltage transformer from a neon sign, boiler ignitor or other equipment.

2 Wire coathangers.

Some people call them 'Jacob's Ladders' but I think Jacob should be left to the God-botherers, it's a climbing arc as far as I'm concerned. I've had to call it this on U-Tube however because everyone else does. The proper name, if you're an engineer is a 'Horn Gap Electrode'. They were originally used for breaking arcs in surge arrestors on early overhead lines.

My first attempts were using my 4 MOT supply despite warnings from people all over the web not to use them because they're lethal. We play with these things precisely for that reason. They gave unsatisfactory results despite having half an Amp available to the arc!

The transformer. 120 Volts in 35,000 Volts out, air insulated. It's very difficult, particularly in the UK to source anything bigger than a 10Kv NST. Something like this is a rare find.

Running your climbing arc at 50 Hz also means you get that classic 'Frankenstein' sound unlike flyback and ignition coil driven gaps that run at high frequency rendering them silent.

Climbing Arc. Done.

See the Climbing arc in action: http://www.youtube.com/watch?v=TcowS9c2Uz4