I grabbed up some of my high voltage videos from my laser site and compiled them into a compilation for you to view.

A quick description of the capacitor discharge setup follows.

Power Source: 15kV 30mA Neon Sign Transformer using a full wave bridge rectifier. Each stage was built of 30 1n4007 diodes wired in series to provide full bridge rectification of the neon sign transformer power source.  These diodes were spiral wound and inserted into a 1″ piece of PVC tubing with bolts and wing nuts on the caps. Rectified voltage of the Neon Sign Transformer is about 21,000 volts.

Capacitor Used: Commercial Energy Storage Capacitor (non-PCB oils) in steel casing.  Weight is approx 125 pounds, rated 170uF at 10,000 volts.  Total energy storage capacity is 8500 joules.

Discharge Conductors: Large copper strapping with holes, commonly used to secure plumbing, etc.

Capacitor Charging Circuit: In order to isolate the capacitor and high voltage sources from the operator I used an all pneumatic system.  The charging system consisted of a custom relay built with a pneumatic cylinder.  the piston of the cylinder was connected to the HV power source, and when activated through a lever valve the piston would extend and it’s end would contact a copper plate to complete the charging circuit. Once the capacitor was charge the valved would be closed, which would shunt air into the opposite site of the pneumatic cylinder and retract it.

Capacitor Discharge Circuit: The discharge circuit was similar to the charge circuit, using the same type of pneumatic cylinder.  The difference is that I had a block with two carriage bolts mounted in it, and the pneumatic cylinder, when transitioned would press a copper shorting bar against the two carriage bolts in series to complete the discharge circuit.  This created quite a spark at the discharge points.  When I do this again I would have used a pneumatically fired triggered spark gap.

Charge and Discharge Sequence: The process was pretty straight forward.  Once a previous discharge was complete we would use the manual discharge bar (10 foot pole with a copper bar across the tip) to discharge the capacitor completely.  The capacitor would be shorted as the new target was configured (I would use an additional pneumatic circuit to short the capacitor to make life easier in the future).  The discharge circuit would be opened and the charge circuit would be closed, allowing the capacitor to be charged. This took quite a while as a 15kv 30ma NST is about 750 watts and it took time to reach the 10kV range on the capacitor.  When the energy storage capacitor was up to voltage the valve for the Neon Sign Transformer was opened, disconnecting it from the circuit.  Within a few seconds ‘FIRE!’ would be called and I would close the firing pneumatic valve, connecting the load to the capacitor with predictable results.

I want to state clearly that this is just a description of my experiments and it is not an instruction manual! I practiced best safe practices to my knowledge after a lot of reading and research. I worked very hard to isolate myself and anyone nearby from the high voltage components of the system by using long pneumatic tubes, practicing multiple-person ‘security’ around the capacitors and loud and clear verbal communication throughout the entire process. I protected the people who assisted me by placing large solid objects (a Pontiac) between ourselves and the discharge target. I do not recommend that you attempt to do these type of experiments even if you think you’ve done things to protect yourself. High energy systems are not forgiving and you more than likely will not get a second chance if you make a minor mistake.

Friends and Safety: I had two good friends who were helping me with this setup and the discharges. I spoke at length, probably too much, to the extent of the physical dangers from this setup and we arranged a verbal signaling system where we shouted out our intentions, discussed the risks and basically covered everyone’s safety before we ever charged or discharged anything.  In the location I was at we were at least 1/2 mile from any other homes or other occupied buildings. (remote countryside)

Anyways, enough with the jibba-jabba, here is the video of some of the capactor discharges, I hope you enjoy them.  If you have any questions please feel free to comment below and I’ll answer.  Comments are ‘screened’ to eliminate spam, but positive or negative I will let ‘real’ comments through, I appreciate your input.

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