[sdiy] Transformer question

[Bert Schiettecatte]

Hi Scott,

Thanks for the info. Why does the core have to be sheets of iron
seperated by an insulating material, and not a solid core? 
I have been trying to find a make-your-own transformers tutorial on the
net including all the math and details but haven't found anything. 

bert

-----Original Message-----
From: owner-synth-diy at dropmix.xs4all.nl
[mailto:owner-synth-diy at dropmix.xs4all.nl] On Behalf Of Scott
Gravenhorst
Sent: donderdag 22 juli 2004 16:05
To: synth-diy at dropmix.xs4all.nl
Subject: Re: [sdiy] Transformer question


I think you need iron, not aluminum.  These contactless charge systems
are based on a transformer principle, one half of the transformer is
inside the device, the other half is part of the charger/holder.  In
fact, I believe that there have been implanted medical devices made that
are powered or charged this way through the skin.

A transformer has an iron core made of leaves or sheets of iron
separated by an insulating material such as varnish.  You could probably
make a device by taking a transformer apart (preferably, one with a
burned out coil so you're not destroying something useful) but remember
that the sheets of iron must remain unsulated from each other.  If you
cut through the core, you'll have to deal with that.

"Bert Schiettecatte" <bschiett at etro.vub.ac.be> wrote:
>Hi All,
>
>After getting a Braun 3D toothbrush I was impressed with the 
>contactless charging mechanism that was used. I went on the net and 
>started searching for some info and decided to try my own contactless 
>charge transfer DIY project. To start, I took two square bars of 
>aluminum, about 1cm x 1cm x 5cm in dimensions. I wrapped standard 
>isolated solid core wire around them (28 turns), I think the wire 
>thickness is like 24 AWG or whatever the standard wire is used in 
>solderless breadboards (a little thicker than wire wrap wire). I was 
>hoping to hook up one of the two inductors I built to an AC power 
>supply (say 5V, 500mA), and hook the other one up to a multimeter 
>measuring volts, then bringing the two inductors close to each other 
>and hoping to get some current or voltage transferring from one 
>inductor to the other one. Of course it doesn't work. What am I doing 
>wrong here? I am totally clueless in basic electronics but I can 
>program in C++ :-)
>
>Any comments highly appreciated.
>
>bert
>

---------------------------------------------------------
- Where merit is not rewarded, excellence fades.
- Hydrogen is pointless without solar.
- What good are laws that only lawyers understand?
- The media's credibility should always be questioned.
- The only good terrorist is a dead terrorist.
- Governments do nothing well, save collect taxes.

-- Scott Gravenhorst | LegoManiac / Lego Trains / RIS 1.5
-- Linux Rex         | RedWebMail by RedStarWare
-- FatMan: home1.gte.net/res0658s/FatMan/
-- NonFatMan: home1.gte.net/res0658s/electronics/
-- Autodidactic Master of Arcane and Hidden Knowledge.