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'[EE]:: Inductive power transfer over 1 metre + at '
2012\02\07@081151 by RussellMc

face picon face
Much rubbish is written about IPT (Inductive Power Transfer) and many
patents seem to be trying to endlessly reinvent things that Tesla
played with. Or Prof Don Otto ** :-).

BUT it seems like Stanford may have found a way of increasing the
range over which very high efficiency transfer can be achieved
Their examples show transfer of around 97% efficiency at ranges of
about 1 metre and somewhat more than 80% at 3 metres. See figure 4 in
the free access paper below.

Their "enabling technology" appears to be "metallic planes" behind the
coils relative to an axis running between the coils. I've only glanced
at the paper so far but it looks promising - with the best efficiency
topology also being the most convenient one for many applications.

          http://www.stanford.edu/group/fan/publication/Yu_APL_99_214102_2011.pdf

It does appear at first glance * as if they may be reinventing a
near-field version of the Yagi-Uda antenna, in which case their
patents may be somewhat shaky.

            http://en.wikipedia.org/wiki/Yagi-Uda_antenna

Automotive on-highway recharging using this technique

              http://www.gizmag.com/stanford-wireless-ev-charging/21321/?utm_source=Gizmag+Subscribers&utm_campaign=4686329cac-UA-2235360-4&utm_medium=email

____________________

** 1971 IPT work - the late Don Otto, Auckalnd University.

           http://en.wikipedia.org/wiki/Wireless_energy_transfer

Says:

   ** 1971: Prof. Don Otto develops a small trolley powered by
induction at The University of Auckland, in New Zealand.[citation
needed]

I "drove"  it at one stage :-)



  Russell McMahon
  Applied Technology ltd

___________________________

* proper reading may show this impression to be wrong

2012\02\07@082753 by John Gardner

picon face
At 10 MHz 97% efficiency may not be enough to wave off  FCC
black helicopters..

2012\02\07@083831 by RussellMc

face picon face
On 8 February 2012 02:27, John Gardner <spam_OUTgoflo3TakeThisOuTspamgmail.com> wrote:
>
> At 10 MHz 97% efficiency may not be enough to wave off  FCC
> black helicopters...


Near Field / magnetic is the intention.
Keeping it that way is the trick.


         Russell

2012\02\07@122525 by Bob Blick

face
flavicon
face
13.56 MHz ISM band is close and the next two harmonics are also ISM. But
transmitting power at that frequency might keep my RFID access card from
working :(

Cheerful regards,

Bob


On Tue, Feb 7, 2012, at 05:27 AM, John Gardner wrote:
> At 10 MHz 97% efficiency may not be enough to wave off  FCC
> black helicopters...

-- http://www.fastmail.fm - Email service worth paying for. Try it for free

2012\02\07@123756 by Yigit Turgut

picon face
Actually it's the electric field which is being transmitted, not magnetic field.

On Tue, Feb 7, 2012 at 3:32 PM, RussellMc <.....apptechnzKILLspamspam@spam@gmail.com> wrote:
> On 8 February 2012 02:27, John Gardner <goflo3spamKILLspamgmail.com> wrote:
>>
>> At 10 MHz 97% efficiency may not be enough to wave off  FCC
>> black helicopters...
>
>
> Near Field / magnetic is the intention.
> Keeping it that way is the trick.
>
>
>          Russell
>
>

2012\02\07@143047 by Robert Rolf

picon face
The Stanford paper clearly says"

"Power transfer
between the resonators occurs in the near-field regime through
the magnetic field. The use of magnetic field as the coupling
mechanism is important for safety reasons and also minimizes
interference effect by off-resonant external dielectric objects."

On Tue, Feb 7, 2012 at 10:37 AM, Yigit Turgut <.....y.turgutKILLspamspam.....gmail.com> wrote:

> Actually it's the electric field which is being transmitted, not magnetic
> field.
>

2012\02\07@143828 by Yigit Turgut

picon face
I was referring to the original work of Tesla.

On Tue, Feb 7, 2012 at 9:30 PM, Robert Rolf <EraseMERobert.Rolfspam_OUTspamTakeThisOuTualberta.ca> wrote:
> The Stanford paper clearly says"
>
> "Power transfer
> between the resonators occurs in the near-field regime through
> the magnetic field. The use of magnetic field as the coupling
> mechanism is important for safety reasons and also minimizes
> interference effect by off-resonant external dielectric objects."
>
> On Tue, Feb 7, 2012 at 10:37 AM, Yigit Turgut <y.turgutspamspam_OUTgmail.com> wrote:
>
>> Actually it's the electric field which is being transmitted, not magnetic
>> field.
>>
>>
>

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