Re: gEDA-user: [OFF] high current amplifier

[Peter Clifton <pcjc2@xxxxxxxxx>]

On Wed, 2009-05-20 at 11:27 -0500, Mark Rages wrote:
> On Wed, May 20, 2009 at 11:16 AM, Levente Kovacs <leventelist@xxxxxxxxx> wrote:
> > On Wed, 20 May 2009 10:48:53 -0500
> > Mark Rages <markrages@xxxxxxxxx> wrote:
> >
> >> What kind of transient are you trying to simulate?  Maybe it would be
> >> easier to make a circuit to add the transient to mains power, instead
> >> of recreating mains power with an amplifier.
> >
> > 230V times 100A is something I dont want to even calculate.
> >
> > --
> 
> You need a high-current, low-voltage transformer:
> 
> http://www.cooperhandtools.com/brands/CF_Files/model_detail.cfm?upc=037103079480

I'd second the idea of using a transformer, although you'd have to check
the resistance of the filaments on those soldering guns to be sure what
currents they would actually deliver.

You might consider how to get wider bandwidth than the 50/60Hz that
these transformers are probably designed for... One option might be to
deliberately choose a transformer with a higher voltage rating than you
need. (E.g. feed a 240V transformer from 110V). The lower voltage should
keep the flux levels in the core down, and (hopefully) help with the
bandwidth of the system.

It isn't too hard to obtain the required currents from a chunky H-bridge
and a suitable PWM generator. It doesn't need a significant power level
to achieve, and in my case, I used the resistance + inductance of about
10metres of fat cable as the load.

-- 
Peter Clifton

Electrical Engineering Division,
Engineering Department,
University of Cambridge,
9, JJ Thomson Avenue,
Cambridge
CB3 0FA

Tel: +44 (0)7729 980173 - (No signal in the lab!)



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