Re: High Power Dimmer, SS Relay ?inverter?

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Malcolm Watts by way of Terry Fritz <twftesla-at-qwest-dot-net>" <m.j.watts-at-massey.ac.nz>

Hi Jason,

On 7 Jul 01, at 10:01, Tesla list wrote:

> Original poster: "Jason Petrou by way of Terry Fritz
<twftesla-at-qwest-dot-net>" <jasonp-at-btinternet-dot-com>
> 
> Neilster,
> 
> I am planning an inverter system that will run up to 500W - I was going to
> have the fets chopping the DC thru the transformer at 50Hz, but since its
> just a simple 555 timing circuit with a varable resistor controlling the
> resonance, then I can run it anywhere between about 1Hz and 1800Hz (the
> saturating frequency of the xfmr core).

You will certainly learn everything there is to know about core 
saturation if you run the transformer at 1Hz.

 If I use a line filter after it, and
> a protection network (thx terry ;) after the NST then I could probably use
> the inverter for TC use. With a scope I could get the frequency exact... It
> would be interesting to see the effects of high frequency input  for TC
> use!!!

Are you talking about CW drive?
 
> On the subject does anyone have a design for a High Powered H-Bridge circuit
> (about 50A) because I would prefer to use 'proper' AC rrather than square
> DC....
> 
> Thanks,
> Jason
> 
> Geek # 1139 Rank G-1
> www.thegeekgroup-dot-org

I think some basic electricity should really come first ;)  You won't 
get "proper" AC from an H-bridge. It is a synthesized AC formed by 
PWM'ing the bridge, the modulating frequency being the desired output 
frequency. By that I mean that there will be some high frequency 
switching components in the output. Of course you could go linear but 
then your efficiency would drop in inverse proportion to the amount 
of heatsinking necessary to keep you power devices alive.

Malcolm