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Re: [Amps] MW Oven Transformer question

To: craxd1@verizon.net, amps@contesting.com
Subject: Re: [Amps] MW Oven Transformer question
From: Alek Petkovic <vk6apk@eon.net.au>
Date: Wed, 22 Mar 2006 06:16:46 +0800
List-post: <mailto:amps@contesting.com>
To reinforce what Will has just said, there is a good article on a ht 
supply in this month's edition of "Amateur Radio", the magazine for members 
of the Wireless Institute Of Australia.

The article is by Drew Diamond, VK3XU and it uses 2 of the transformers 
with the primary windings in series and the secondaries in series or parallel.

I do not have a website but I can email a pdf of the article to somebody 
who does.

73, Alek.
VK6APK

At 03:30 AM 22/03/2006, Will Matney wrote:
>Gerald,
>
>My guess by seriesing two will drop the flux density in each to around 10 
>kilogauss as each will have 1/2 the line voltage across it. That's well 
>below the bottom of the knee and in the linear region. It will raise the 
>power capability X2 also, but I can't say how much without knowing the 
>core dimensions. Two this way though will run as good or better than a lot 
>of off the shelf linear transformers because of the low flux density. This 
>means the efficiency is really high, probably 95% for a rough guess.
>
>Best,
>
>Will
>
>
>*********** REPLY SEPARATOR  ***********
>
>On 3/21/06 at 2:22 PM TexasRF@aol.com wrote:
>
> >Thanks Will and John; I now have an understanding of the heating issues
> >with
> >the MOT. It appears that these transformers are really a poor choice for
> >continuous operation such as a filament power source. Two transformers
> >with the
> >primary and secondary windings series connected will work and for  testing
> >the
> >traveling wave tubes is the quick method to be used.
> >
> >Many thanks for your help in my continuing education!
> >
> >73,
> >Gerald K5GW
> >
> >
> >
> >In a message dated 3/21/2006 11:10:15 A.M. Central Standard Time,
> >craxd1@verizon.net writes:
> >
> >If you  want to add turns to the primary (if there's enough room, and
> >should
> >be with  the secondary removed), you can do a simple test to see how many
> >turns to add.  First, use the formulas I published last week about
> >figuring the
> >core size and  number of turns to find the correct number of turns for the
> >core
> >size you  have. Next, connect the primary to 120 Vac and wind a 10 turn
> >coil
> >secondary.  Take that secondary voltage and divide it by the 10 turns.
> >That
> >will be the  turns per volt. Last, wind the extra turns you've found you
> >need by
> >the  formulas and the known turns per volt. One good thing on this
> >transformer
> >in  question, the primary is on the inside. If on the outside, you'd be
> >screwed on  removing the secondary.
> >
> >Best,
> >
> >Will
> >
> >*********** REPLY  SEPARATOR  ***********
> >
> >On 3/21/06 at 11:42 AM John Popelish  wrote:
> >
> >>TexasRF@aol.com wrote:
> >>
> >>> Not what I hoped  to hear but I appreciate the good info!
> >>
> >>If you have a supply  of this kind of landfill, you might put two
> >>similar units side by  side, wire the primaries in series (effectively
> >>halving the volts per  turn, so eliminating the saturation problems).
> >>Then you can knock the  shunts out and wind a similar secondary on each
> >>(doubling the number  of turns to compensate for the half primary
> >>voltage) and wire those  two secondaries in parallel.  This gives you a
> >>reasonably  efficient transformer (that won't overheat without a fan)
> >>with about a  kVA rating.
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> >
> >
> >
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> >
> >
> >
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>
>
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