Re: An Economical Magnecharger (inductive charger)

[Lee Hart <leeahart@earthlink.net>]

Justin Southam wrote:
>             what is the impact of not interleaving?

Think of a transformer somewhat like a torque converter. If the primary
and secondary are tightly coupled, then efficiency is highest and we
have a precise ratio between input and output voltages. Like a torque
converter or clutch that is locked up; nearly 100% efficiency, exactly
the same speed in and out.

As you separate the windings, the coupling gets looser; it can "slip"
like a torque converter, which lowers efficiency. But it can also change
the voltage and current ratios (like a torque converter can multiply
torque and reduce speed).

> If we mount the primary bobbin and the I stack in a frame with a
> handle, can't we slide the bobbin over the E then the I stack meets
> the E stack as normal with maybe a quarter turn of the handle to lock
> and clamp (some sort of taper arrangement) them together.

I think you mean like this (view with fixed width font):
 ___________________
|                   |
|___________________| paddle assembly
     PPP     PPP
     PPP     PPP

 ___     ___     ___
|   |   |   |   |   |
|   |   |   |   |   |
|   |SSS|   |SSS|   | secondary assembly
|   |SSS|   |SSS|   |
|    ---     ---    |
|___________________|

Yes, this works. It is exactly how I tried the idea, with a little 6v
2amp Radio Shack transformer. I took the mounting bracket off, and the
core fell apart into two pieces; the I's and the E's with the plastic
bobbin. I sawed the plastic bobbin in half so the primary and secondary
were on separate pieces.

It worked just as well (i.e. as badly) as it did before I took it apart.
It buzzed and hummed unless you clamped the core tightly together.
Efficiency was low, but no lower than it was when I started, due to the
substandard core and undersized wire it was built with. The core pieces
were not precisely cut, so there were noticeable air gaps between them
even when clamped as well as possible.

I think you could build a better version of this, by starting with a
quality transformer. But the paddle will be heavier (the I's are longer
and thus heavier than just enough core to fit inside the primary). And
it is a mechanically awkward assembly.

Thus I was trying to improve on the design mechanically.
-- 
Lee A. Hart                Ring the bells that still can ring
814 8th Ave. N.            Forget your perfect offering
Sartell, MN 56377 USA      There is a crack in everything
leeahart_at_earthlink.net  That's how the light gets in - Leonard Cohen