High Voltage (600VDC)

[Krumlink]

Ugh, found what I was looking for. Overall none of you came close

Another Coilgun Site

Thanks anyways.

 

[Blueteeth]

Why not just design a boost convertor? Its pretty simple and only becomes 'tricky' when you want half decent efficiency....and use a transformer instead of a plain inductor.

You could use a 555 timer, with backward step down 'UK' transformer (230 - 6v @ 12w). Put in 12V and you'll get 460v on the output....clever use of the 555's pin, you could boost that to 800v. only 10mA current though

Blueteeth

 

[Krumlink]

Not to mention it would be huge. This circuit is compact and easy to integrate.

 

[Hero999]

Your circuit is a boost converter.

Good luck getting 600V from it at any decent power level though.

Look at the Maxim, Linear and Nationtal websites for boost converters and you're bound to come across some good ideas, even if they need adapting to get 600V.

 

[Ubergeek63]

Maybe you can get some insight from the following article.
**broken link removed**

Sleazy apps engineers! I did that before that article was printed and he got $100 for submitting it.

I do not think they should pay the apps engineers to advertise for their companies (a linear tech apps engineer using a linear tech component in this case)

 

[Ubergeek63]

Your circuit is a boost converter.

Good luck getting 600V from it at any decent power level though.

Look at the Maxim, Linear and Nationtal websites for boost converters and you're bound to come across some good ideas, even if they need adapting to get 600V.

The circuit mikebits posted the link to will do it without the diode capacitor tripler.

 

[Blueteeth]

Not to mention it would be huge. This circuit is compact and easy to integrate.

Who said anything about huge? Transformers are available in 1" cubes. And a 555 timer cicruit is nothing, even if you decide to go through-hole. A MOSFET could handle reasonable current with a small heatsink. Ever seen inside a PC's PSU? nothing major in there and they run at 600W+

If you want to charge a 960uF cap bank to 700-800V in seconds. Do the maths (I refuse to exclude the 's' ^^) , work out E, then you can work out what power you would need for a certain charge time. Of w're talking 20 seconds, then thats, what...er..12W? At 700V thats 18mA.

As someone has already pointed out, getting a large voltage from a boost convertor is tricky. Sure 12 -100V is simple enough...but 600? I'm sure theres plenty of info on the web about this. Not only for coil guns but exploding wires, lorentz cannons, rail guns...all require large joule cap storage for anything fun.

Blueteeth

 

[Ubergeek63]

Who said anything about huge? Transformers are available in 1" cubes. And a 555 timer cicruit is nothing, even if you decide to go through-hole. A MOSFET could handle reasonable current with a small heatsink. Ever seen inside a PC's PSU? nothing major in there and they run at 600W+

If you want to charge a 960uF cap bank to 700-800V in seconds. Do the maths (I refuse to exclude the 's' ^^) , work out E, then you can work out what power you would need for a certain charge time. Of w're talking 20 seconds, then thats, what...er..12W? At 700V thats 18mA.

As someone has already pointed out, getting a large voltage from a boost convertor is tricky. Sure 12 -100V is simple enough...but 600? I'm sure theres plenty of info on the web about this. Not only for coil guns but exploding wires, lorentz cannons, rail guns...all require large joule cap storage for anything fun.

Blueteeth

108J is not that much. J=W*S so to charge his 600uF to 600V takes 4 seconds at 27W, 35W or 5 seconds with losses.

 

[Krumlink]

@Blueteeth: No, Dknuygen's military charger.

It takes 5 seconds for that circuit to charge 288J. READ THE POSTS.

 

[Blueteeth]

I did read that post....I was merely plugging in numbers for an example. Nothing wrong with my maths I'm not sure what you're trying to say?

 

[Ubergeek63]

You could use a cold cathode tube inverter with a variable DC voltage on the input and a rectifier on the output.

Good idea, I am surprised I did not think of it... particularly since I just finished designing one!

That may or may not work. A crappy inverter will, but the good regulated ones will register an open tube and shut down.

The other thing is that most of them are only 4-6W and would take close to a minute to charge the cap. if you are a bit sneaky you might be able to get one of the good ones to work with the added advantage of the inverter automatically shutting down once it is charged.

 

[Krumlink]

what i meant was that on that website where I got the circuit he said that he could charge at that rate. (banana nut muffins OMFG!)

 

[Blueteeth]

what i meant was that on that website where I got the circuit he said that he could charge at that rate. (banana nut muffins OMFG!)

Yep, I saw that. Charging to 250V. The post topic is 600VDC. There is an obvious difference.

All I was doing was trying to steer you in the right direction for designing a boost converter for >300v, putting numbers into equations and giving you an idea of charging current vs charge time. I have no idea what you are on about. But I'm sure you've got it under control.

Blueteeth