Re: transferring electrical energy through metal wall

[EMAIL PROTECTED] (Everett M. Greene) wrote:

>Jim Klein <[EMAIL PROTECTED]> writes:
>> [EMAIL PROTECTED] ([EMAIL PROTECTED]) wrote:
>
>> >I am doing a project to transfer electrical energy (about 1 W, pulsed)
>> >through the metal wall (5-10 mm thick) of a pressurised vessel with an
>> >efficiency 10%. I have considered the options to transfer acoustically
>> >or optically, but the only suitable method turned out to be the
>> >magnetic one. A primary coil on one side of the wall is fed with
>> >pulsing/AC current, the resulting pulsing/AC magnetic field is
>> >transferred through the metal wall, and the secondary coil on the
>> >other side transforms the magnetic field into electrical current.
>> >
>> >The only problem was that the steel wall absorbed all of the magnetic
>> >field. I had to drill a hole in the wall of the physical model, so
>> >that to allow the passage of the magnetic field. I inserted the
>> >primary coil into the hole perpendicularly to the wall, and put the
>> >secondary coil behind the wall with its axes parallel to the wall (for
>> >certain reasons). Without the metal wall, the configuration of the
>> >primary/secondary coil worked fine. But the introduction of the wall
>> >into the system brought the voltage in the secondary coil close to
>> >zero. It got me thinking -- I decided that even if the magnetic field
>> >lines could get through the hole in the wall along the inserted coil
>> >core, the lines had to return to the other magnetic pole of the
>> >primary coil. And this was where the metal wall was the barrier to the
>> >lines ! I thought that I would have to enlarge the hole and introduce
>> >an air (magnetically easily penetratable) gap between the primary coil
>> >and surrounding metal.
>> >
>> >The question is, how large the hole has to be, so that to allow the
>> >return passage of the magnetic field lines into the opposite pole of
>> >the primary coil ? I thought I could use a simulation package to
>> >analyse the distribution of magnetic lines, and thus I could find out
>> >the effect of the size of the wall's hole on the efficacy of
>> >transmission of magnetic energy through that hole. Can you recommend
>> >me the simulation package which has a short and not-so-steep learning
>> >curve ?
>> >
>> >Your advice would be appreciated.
>
>> I aready told you how.
>> 
>> 1/2" high speed steel drill bit and drill followed by an extension
>> cord. :-)
>
>You're being very generous with the size to transfer 1 W.
>
>This OP reads like a blond joke:  The blond needs to transfer
>energy into a sealed container but can't get the magnetic
>flux to pass efficiently so drills a hole to help.

How'd ja know. :-)