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What kind of switch is best for a coil gun? ? Answered

Im making a coil gun for a final project and I am wondering what kind of switch to use to fire the gun. I cant find a powerful enough switch, the highest rating ive found is 480v but they just burn out. I'm using a knife switch know but it robs a lot of the potential power and the gun doesn't shoot as far. I am using 15 300v 100uf capacitors in parallel

5 Replies

Kiteman (author)2012-06-11

Why not make your own switch?

Squeeze to contact two thick pieces of metal, you could wrap it in a layer of rubber (say, bicycle inner tube), and build it into the grip of the gun (squeeze the grip to fire the gun).

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Jack A Lopez (author)Kiteman2012-06-12

I think I have seen this done by way of a modified rat trap. By "seen" I mean I saw it on Youtube, here, at  t=14s:

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iceng (author)2012-06-11

Here is a switch that can handle Very high Currents and as much
voltage as a mylar thickness determines.

The radio or light beam causes the mosfet to red heat a failure
in the insulating between the 1" thick iron plates and a Bang later
you have a discharged capacitor bank and a hot launching coil.


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steveastrouk (author)2012-06-11

You're looking at the wrong rating. You need extremely high current handling as WELL as a high voltage isolation, assuming you HAVE a high voltage in your cap banks.

The BEST thing would probably be a really big Thyristor.

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iceng (author)steveastrouk2012-06-11


That is an SCR silicone controlled rectifier

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