Hi John,
I had the opportunity to examine one of those last year courtesy of the "curb
exchange".
Many are the reasons it would not be suitable as an amplifer supply:
There is no input filtering, so the output waveform follows the rectified
line.
The controller IC's interface would not allow for reasonable (quick response)
closed loop operation.
The topology is a forward converter which would not allow for a wide range of
power output.
The transformer itself is pretty cute, wound with Litz wire.
So...
Add real input filtering, a soft start, change the controller, install an H
bridge of FET's or IGBT's and their drivers, include some feedback from the
secondary side and one would have a KW (but, only a KW!) supply suitable for
perhaps a pair of 813's or 4cx250's.
Note that the only usable parts are the input rectifier, output rectifiers,
and the transformer.
Or just give the thing to a friend for use as a Microwave Oven and build
something more apropos from scratch.
73 & Good morning,
Marv WC6W 310 649 3111
--- On Mon, 1/17/11, G3UUT <amps@grebe.plus.com> wrote:
> From: G3UUT <amps@grebe.plus.com>
> Subject: Re: [Amps] Transformer-LESS advice
> To: amps@contesting.com
> Date: Monday, January 17, 2011, 8:01 AM
> On the subject of switched mode HV
> psus, I've just come across the
> following which may be of interest, especially if anybody
> has any
> information on the (probably custom) control IC.
>
> http://www.vk3hz.net/amps/Microwave_Oven_Inverter_HV_Power_Supply.pdf
>
> 73
> John G3UUT
>
> On 15/01/2011 08:17, Ian White GM3SEK wrote:
> > Rob Atkinson wrote:
> >> Well, Watts Unlimited was owned by W9QQ so if you
> could contact him,
> >> you might be able to get some information about
> it.
> >>
> > W9QQ died a few years ago. The Watts Unlimited company
> does not seem to
> > be active, but the design rights to the HV switcher
> must still belong to
> > somebody.
> >
> > Although a number of these HV switchers were made, and
> are possibly
> > still in use [1], the design did have some problems.
> One was the very
> > poor output regulation - according to the user
> documentation, the output
> > voltage dropped from 3600V @ 100mA to 2600V @ 1.0A.
> (We can only
> > speculate why the design did not include active
> voltage regulation;
> > there must have been a reason.)
> >
> > The other major issue was on the 115/230V mains input
> side, with very
> > little filtering and a serious confusion between the
> mains neutral,
> > 'chassis ground' and the green-wire earth.
> >
> >
> > [1] http://www.gare.co.uk/k5and/8877.htm
> >
> >
>
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>
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