Re: Request for help with air core transformer/power transfer system

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: David Speck <dave@xxxxxxxxxxxxxxxx>

Dave and list,
Thanks very much to all who responded to my query about transmitting a 
little power through glass with analyses both simple and complex.

I have to admit to getting more than a little sentimental (or is it just 
mental?) around the holiday season, and I want to make a nice show scene 
inside an old (150 years!)  glass terrarium jar.  I have some small LED 
Christmas lights that I'd like to light inside the jar, but because of the 
age and value of the container, I'd rather not ruin it by drilling 
it.  With my luck, it would break just as I finished the hole, anyway.
It would also be neat to lift the scene off its pedestal and have the 
nephews and nieces try to figure out how the lights were being powered.
There isn't time to experiment with the multi kHz arrangements, but I might 
take a stab at the doubled E/I core system.  I only need a few volts inside 
the jar, so I don't think I'd need a lot of turns inside.
I think I'll try a couple of scrap transformers from MWO control boards.  I 
must have 50 of them from salvaged ovens laying around.  I'll see what kind 
of secondary voltages I can get with a 1/4" separation.  I suspect that a 
larger core set where the width of the pole pieces is larger than the 
interposed gap would be a more efficient setup, but my space is a bit 
limited.  Just have to give it a try.
Best wishes for a happy and healthy holiday season.
Dave

Tesla list wrote:

> Original poster: "Dave Halliday" <dh@xxxxxxxxxxxxxx>
>
> I would try two filament transformers with an E+I core system. Pop the I
> lamination off and place them face to face.
>
> Is there a reason you cannot go through the glass?  Drilling glass is
> very doable. Use brass "hobby" tube as your bit and use 600 grit
> abrasive powder and water (with a bit of soap) as the cutter - build a
> dam out of toothpaste to contain the slurry.  Use a drill press and feed
> very very _very_ slowly.  You can then use any manner of electrical
> feed-through.