Re: Rogowski coils

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "David Sharpe by way of Terry Fritz <twftesla-at-uswest-dot-net>" <sccr4us-at-erols-dot-com>

Terry, ALL

One manufacturer of self balancing Hall Effect I sensors I've used on projects
is LEM (www.lem-dot-com).  Bandwidths to several hundred kHz for sure.  Used
in variable speed drives, and railroad/light traction service.  Need
+/-12-15vdc
to power, output is 0-10V scaled to FSD current reading of sensor.  Watch
mounting, they are polarity (current direction) sensitive.  Units up to several
hundred amps in standard catalog.

Regards and Happy New Year to all...

Dave Sharpe, TCBOR
Chesterfield, VA. USA

Tesla list wrote:

> Original poster: "Terry Fritz" <twftesla-at-uswest-dot-net>
>
> Hi All,
>
>         It would appear that Rogowski coils may be a fairly promising way to
> measure primary currents in Tesla coils.  It is not straight forward and
> would need some R&D work but the advantage of super high current ability is
> really neat.  One of the best papers on this is at:
>
> http://www.pemuk-dot-com/pdf_files/816epe99.pdf
>
> Many of the commercial designs (that are published) seem to be rather
> limited by the simple op-amp integrators.  "I" would think one would not
> worry with the integrator but rather pick up the di/dt waveform with a
> digital scope into a data file and let Excel do the integration.  That
> would do away with a lot of the mess involved.
>
> The high voltage could fairly easily be shielded by putting the coil in a
> metal (non-ferrous) box with a split in it to avoid the shorted turn effect
> (although the split may have to withstand 10's of kV...).
>
> I always worry about current transformer type circuits since if the burden
> resistor fails, it forms sort of a little tesla coil with the output being
> the scope's input electronics =:O
>
> I will put this info away for a day when the need comes up.  Thanks to all
> who helped me spell it and all ;-)
>
> I'll look into Hall sensors next...
>
> A great overview page of current sensors is at:
> http://www.pcim-dot-com/articles/1998/art0001/art1.html
>
> Cheers,
>
>         Terry     Happy New Year!!