I highly advise you to
        1) rethink using a push-pull for 3kW (there *will* be losses and it
is not 100% efficient), and
        2) read at least some introductory material

Please understand that point 2 is not meant to be derisive. But this is an
extremely involved process. You cannot separate the transformer from you
topology. They are intertwined. And ferrite selection is also influenced by
the topology. In fact, ferrite selection and transformer design tend to be
somewhat iterative. You need to understand why you might not want to use a
push-pull at these power levels. A decent introductory book is by Abraham
Pressman. There are a lot of other books, but this one is pretty good at
explaining the basic differences between the topologies and providing
general background

To reiterate, this is NOT a trivial subject. There is a lot of information
you need to know. There are massive amounts of books and college courses
(mainly post-grad, at least in my time) aimed at this subject. No one book
is really complete with all the details. The list cannot realistically hope
to give you all of this information. There is just too much of it. You need
at least a background so you can ask more specific questions.

And finally, there is no answer to your question, because it really depends
on the rest of the design.


> -----Original Message-----
> From: Justin Grimm [mailto:Justin.Grimm@SOUTHCORP.COM.AU]
> Sent: Wednesday, August 21, 2002 11:31 AM
> To: PICLIST@MITVMA.MIT.EDU
> Subject: Re: [EE]: How to make a transformer
>
>
> The input is a push pull arrangement so there will be 24 v at
> any time on
> the input.
>
> Justin
>
> -----Original Message-----
> From: Thomas Sefranek [mailto:tcs@cmcorp.com]
> Sent: Thursday, 22 August 2002 0:00
> To: PICLIST@MITVMA.MIT.EDU
> Subject: Re: [EE]: How to make a transformer
>
>
> You are NOT up to the task if you have to ask.
> Designing a 3,000 watt inverter, is a NON-trivial task.
> Finding a core that can handle that gauss will be a daunting
> challange.
> BTW: 48 volts times 18 is NOT 432 volts.
> Trying to wind a 50 AMP primary is a good challange too.
>
> > -----Original Message-----
> > From: pic microcontroller discussion list
> > [mailto:PICLIST@MITVMA.MIT.EDU]On Behalf Of Justin Grimm
> > Sent: Wednesday, August 21, 2002 9:33 AM
> > To: PICLIST@MITVMA.MIT.EDU
> > Subject: [EE]: How to make a transformer
> >
> >
> > hi everyone
> > Does anyone know (or know where to get info) on how to
> design an inverter
> > transformer?
> > Its input is 24-0-24 V square wave 100kHz or 20kHz (havn't
> decided yet)
> > Its outputs are- 1x 432 V at 2400W
> > and 1x 12 V at 6W.
> > The turns ratio is 1:18. Do I use a ferrite core? It needs to be
> > as small as
> > possible.
> >
> > How do I design this transformer?
> >
> > Thanks
> > Justin G
> >
> > --
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> >
> >
>
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