Building The Electronics For A Tesla Coil… And Watercooling Them

A few years ago [Patrick] was offered the Tesla coil of a friend of a friend. This was an opportunity too good for him to pass up.

He then began the creation of an Off-Line Tesla Coil (OLTC), where no supply transformer is used. The incoming mains supply is rectified and directly fed into the tank capacitor.

[Patrick] therefore had to build a huge capacitor bank and more importantly his own primary coil, made with a 1.6mm (0.064″) copper sheet to handle the immense current involved. Air cooling the electronics was sufficient until he started using his three phase input supply. As more power involves more heat, a waterblock was designed to cool the main transistor.

Patrick’s write-up is very detailed and worth the read. Once you’re finished with it, we advise you to browse through his website, where a lot more cool projects are described.

5 thoughts on “Building The Electronics For A Tesla Coil… And Watercooling Them

  1. Super build! Love the large quantities of heavy copper conductor ;-)

    Re: capacitors. I once had an idea about trying to cool film capacitors more directly by sanding away the ends to reveal the sprayed metal contact then soldering them to a copper cooling plate with low-temperature solder. Never really pursued it past soldering one capacitor to a bit of scrap copper. Photos here –

    1. The resonant frequency of the secondary and the sphere is around 113khz. Line filtering is in the separate 22KW phase angle control power supply (I’m an electrical engineer) which I will detail in another post.

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