Hi Alex,
The cores are Magnetics 44916-TC-J.
The original article stacks 10 of them (enough core for 8-10 KW!) which
allows for the meager winding.
I did the math long ago; The cores are run at 1200 gauss which results in
circa 60 watts core loss.
73 & Good evening,
Marv WC6W
http://wc6w.50webs.com/
--- On Tue, 3/31/09, Alex Eban <alexeban@gmail.com> wrote:
> From: Alex Eban <alexeban@gmail.com>
> Subject: Re: [Amps] winding an HV transformer
> To: "'Paul Decker'" <kg7hf@comcast.net>, amps@contesting.com
> Date: Tuesday, March 31, 2009, 1:04 AM
> ...none!
> With full wave rectification of a square wave you get the
> peak to peak
> voltage of the secondary as the DC output.
> What scares me after having worked on off line converters
> for about 6 years
> is the primary number of windings: it seems much too low
> and since you give
> no information on the core, I can't verify the number
> of turns. I would
> expect to see 20 turns or so in the primary.
> Please give me more info and I shall try to make sure you
> don't send the
> power transistors to the grave.
> Alex 4Z5KS
>
> -----Original Message-----
> From: amps-bounces@contesting.com
> [mailto:amps-bounces@contesting.com] On
> Behalf Of Paul Decker
> Sent: Tuesday, March 31, 2009 12:37 AM
> To: amps@contesting.com
> Subject: [Amps] winding an HV transformer
>
>
>
>
>
> I've been holding this question for a couple of days
> now, I'm sure it is
> very simple and perhaps I just need some reassurance on the
> answer.
>
>
>
> If you have been following some of this smps discussion,
> I've got 100Khz
> pulsed DC (0 - 340v) which is generated by directly
> rectifing and filtering
> the 240 V AC mains and providing that into an h-bridge.
> The h-bridge dumps
> the 340 V 100Khz square wave into the transformer.
>
>
>
> As the QST article recomends, I've wound the
> transformer with five turns on
> the primary and had calculated that I need 30 turns on the
> secondary.
> Performing some small signal tests, inputting 3.4v pk-pk
> square wave from my
> signal generator yeilds about 20.4 volts pk-pk square
> wave. I believe this
> relationship should be linear and inputting 340 V will
> yeild 2040 volts on
> the secondary.
>
>
>
> At this point the secondary dumps into a full wave bridge
> rectifier followed
> by a filter capacitor. This is where I am
> unclear. When I rectify this
> with the full wave bridge, will I get 2040 * 0.90 or
> will I get 2040 *
> 1.414 as the final DC output? Part of me says I get
> the 1.414 value of
> 2885 VDC, however reading through the handbook, I seem
> to be reading I'll
> get 0.90 the output voltage.
>
>
>
> thanks,
>
> Paul
>
>
>
>
>
>
>
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