Coilgun switch

Hello,

I would like to build a coilgun for a nice rewarding project :wink:

I have made a "super simple mini version" in 10 min. that has only a photoflash capacitor and a coil.

When runing small "pre-tests" I have noticed a huge spark blast from the point were I touch the photoflash capatitor and the coil.

I need a switch that could stop this huge spark from happening, it is waisting elecricity right?

I have a radioshack close to my house

If anyone can help me please do

thanks,

George

Actually, it is not wasting electricity.

When there is a high voltage potential between two points (the contacts of your switch in this case), a plasma channel forms in the air. A plasma channel provides a low resistance path, pretty much like a wire.

So before your switch contacts physically touch, all of the electricity has probably been discharged from the capacitor.

thanks zachtheterrible...

I like your "thats a spicy meatball" thing

George

Well the blast does tend to move the wires apart.

Typically people will use SCRs, but it has to be a huge-ass SCR for a real coilgun, perhaps less for yours.

The other is a spark gap. There are several solutions. One is to have two balls with a stiff spacing, just past the arc distance. However, once the arc is triggered current will flow. It can be triggered by a spark, such as one generated by a zenon tube trigger transformer. Any high voltage particularly with a high dv/dt rate can trigger the ionization. And simply mechanically connecting them works too, like dropping a metal ball through a tube, or if you're foolhardy, a screwdriver with an insulated handle. Or you can make the contacts slap into each other too.

The thing is, those contacts on the cap won't hold up to those surges, each one makes a little pit, soon it looks like the moon.

Coilgun projects are fairly common fodder around the web,
sadly only two really stand out..
Sam Baros over at Powerlabs for the real
homebrew heavy artillery and Evgenij Vasiljev at this addy **broken link removed**

The best hand-held coilgun on the planet ?

WOW!!!!!!!!!

now thats a coilgun!!!!!

thanks,

George

I've seen Sams site, but never seen that hand held one. That is a precision piece of engineering, fantastic design!

tansis said:

Coilgun projects are fairly common fodder around the web,
sadly only three really stand out..
Sam Baros over at Powerlabs for the real
homebrew heavy artillery, Evgenij Vasiljev at this addy **broken link removed**
and Another Coilgun Site at this addy https://www.anothercoilgunsite.com


The best hand-held coilgun on the planet ?

Click to expand...

Use a $3.00 SCR in a small TO-220 package from digikey. Teccor is the manufacture name to select when digikey returns its many results.

In my opinion any spark or any heat created making craters or whatever is energy wasted. This energy will not reach the coil.