On Fri, Feb 17, 2006 at 12:17:39AM -0500, Martin K wrote:
> Peter Todd wrote:
> 
> >Probably the way to go. Another poster mentioned a switch-mode supply
> >from jameco that looks like it'd work, and comes with an impressive list
> >of things it does. Expensive though, I may just find a bigger, higher
> >voltage, transformer and go back to my first diode bridge. I just gotta
> >find a 8v, 50A transformer.
> >
> >  
> >
> I've seen a 240v to 400A 5v transformer. I'm not joking.

Funny how you say that... I did a websearch to find a bigger transformer
and figure out pricing... Sure enough, I found a 220V to 600A 5V
transformer at a surplus place!

Found a 12V 60A transformer too, but I think I'll just go with a
switcher, same price.

> At lower voltages you could almost take a large toroid and wrap 10AWG 
> wire around it to get the voltage you need.

Good idea, I've got a source for cheap, $10 each, 250, 500 and 1000VA
toroids. Real heavy monsters.

> Another option would be a microwave transformer. The primary and 
> secondary are usually separated so you could cut off the HV secondary 
> and wind on a strip of copper foil for the secondary. This is assuming 
> you want something less expensive. It seems like you have a mid-range 
> budget for this project.

Yeah, it's cost something like $1500 already, and I'm looking to sell it
too, so I don't really wanna be messing around with making my own
transformers, making my own power supply was pushing it.

UL listing and all...

> I think you could get a surplus switcher to work. If not one unit then 
> two in parallel through some small value power resistors to share the 
> current.
> I'd be tempted to build my own push-pull switcher with PFC, but I'm that 
> kind of guy.

Haha, that'd be a fun project... Especially for me... I've long
forgotten my calculus, and currently know very little analog
electronics.

Anyway for this project I think I'll just buy a switcher from jameco
like some other posters suggested, but thans for the transformer tips, I
do have projects where that'd really come in handy, projects that I'm
not planning to sell to some poor unsuspecting art collector!

-- 
pete@petertodd.ca http://www.petertodd.ca
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