Krill Labs - High Voltage Source V2.0 (25kV)

About:

I thought I'd revisit my experiments to generate high voltages and build a better HV source. This time using a car's ignition coil, a high power mosfet from an old UPS power supply, and a 2 amp 40v transformer, I was not only able to generate higher voltages, but was able to pump a lot more power through the subsequent arcs.

Construction:

       The general construction of this generater is about the same as the last one, only this time the parts are better, the design process included many calculation and component value revisions, and this model is intended for a much greater purpose than to just make pretty sparks. I intend to eventually use it as the main tank capacitor charger for a Tesla Coil! The third picture shows my tesla coil's rough draft and has this devices ringed off in purple.
       In the first picture below you can see the assembled device. It's core components are the 555 based oscilator, a heafty mofet for the AC switching, the 2amp 40v transformer, a voltage soothing rectifier bridge, the ignition coil, and some discharge terminals.

       Now there are 2 really important factors to make this thing work well. This first is to properly tune your 555 oscilator circuit. It is crucial to find the perfect duty cycle and frequency. If your oscillator is not matched to the natural resonance of the ignition coil, you won't reach the coil's fullest potential. For me to do this, it took a lot of analysis using my o-scope software (waveform below shows the coil's optimal signal) and trial and error.
       The other really important thing is to find a good transister for the AC switching. I went through several of these things and it was actually by accident that I found a great one. I am currently using a power mosfet (IRF630n) recovered from an old UPS. The quality of this part will also play a significant role in the preformance of the ignition coil. My first few transisters aparently weren't transfering enough power because when I put in my latest one, I noticed a huge increase in arc strength and distance. The one you use should have a high frequency response, a high voltage rating, and as high a current limit as possible. Also!! They will get very very hot, so make sure it's on a heat sink with a fan. Even a little fan pointed at it will do wonders.

The final control board includes all the low voltage components neatly mounted to a big piece of plastic.

Things to Overcome:

With the voltages getting so high, things that aren't normally conductive, become conductive! What you can see here, during open circuit operation of the
ignition coil, you get corona (ionized electrical dispersement) all over the place. And 2 insulated wires overlapping passing current.

Also never let your positive and negative electrodes get too close, otherwise the spark will be like an arc-welder's - capable of burning down the house!

Point to Point
Discharging between a stainless steel nail and the ground wire with an alagator clip for increased surface area.

Point to Plate
Discharging between the nail and a wooden block wrapped with aluminum foil for an even greater surface area.

Plate to Plate
Replacing the nail with another plate, you get a jacobs ladder effect, only instead of the arc just rising, it can snake around.

	NAME:	REMARK: