Terrifying Power

4 09 2011

All photos.

Tonight I really experienced the power of the coil power supply. Whoa.

I’ve been working to increase the coil current from ~1.2kA to ~2.5kA.

Previously I discovered the coil discharge path had more DC resistance than expected.

I rewound the Polywell coils with 16 gauge wire (previously 18 gauge).

The 16 gauge DC resistance is 144 mΩ compared to 227 mΩ for 18 gauge wire.

I beefed up other wires on the coil discharge path (4 gauge):

Lets test the wiring with the dummy coil:

I took the power supply up to 100V… a small test charge…

When I fired, the noise from the coil made me flinch. It was never that loud before.

Lets turn up the power!

300V for second test.

When I fired the coil there was lightning! HOLY CRAP.  Look what happened:

The coil fucking wrapped itself around the transformer (electromagnetic forming). Then it discharged to ground:

So I haven’t measured it yet, but I think we are getting more current to the coils.



4 responses

4 09 2011
Stephanie S

To really have fun, put a coin in the middle of the coil, and make sure to sandwich the coil and coin in a plexiglass or other nonconductive (and shatter proof) material. The magnetic force will make the coin actually shrink.

5 09 2011
Triffid Hunter

Now put an aluminium can in the coil, see if you can turn it into a wineglass.

Make sure it’s empty first unless you like sticky sugary beverage all over your protective concrete barrier and anything else in the blast radius ;)

5 09 2011
Raymond Rogers

Great show :)
Off the immediate subject:
I am a little late with this. But if it was me, I would trace out all of the current paths going out and coming back; then I would twist the current carrying wires so as to minimize the area of the current loops by matching the current flows.. Probably wouldn’t make any difference for you purposes, but it’s neater and keeps the stray magnetic fields down.
I’m a little obsessive about this particular thing; but it avoids some problems. It might even clean up your scope traces a little.

29 09 2011
Remy Dyer

What Raymond said. Also – replace the buss bars with thick and wide double-sided PCB – drill holes and use one side as Plus, the other Minus – this will drastically cut the extra inductance in your cap bank, leading to higher peak currents. Like this one : http://hackedgadgets.com/2010/07/16/113-kilojoule-capacitor-bank/

I guess you could series the two banks by having the two pcbs overlap – keeping the current conductors wide and flat, and close to the return path, also wide and flat, will tend to reduce the stray inductance.

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