Rogowski coils

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

Original poster: "Terry Fritz" <twftesla-at-qwest-dot-net>

Hi All,

I did some experiments with my Rogowski coil tonight.

They really do measure current.  The signal level is fairly low so they are
best used for large currents as opposed to mA stuff.  They seem to be
fairly immune to how you place the conductor through them.

The phase response is very good!  They are 90 degrees out (un-integrated
output) and the signals are pure.  The phase is probably stable over a very
wide bandwidth.

Frequency response...  Oops!  looks terrible!!  Has its big "ups and downs"
you could say ;-))

Perhaps with a careful design, one could get them stable over Tesla coils
frequencies (50 - 500kHz).  But there are a lot of "issues" with wide band
amplitude frequency response.  Perhaps I am spoiled by Pearson.  However,
$450 for Pearson compared to 45 cents for Rogowski coil is a big difference!  

I imagine the commercial makers have all the "tricks" figured out.  All
kinds of options on exactly how one winds these things and why...

Work continues...

Cheers,

	Terry