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Re: Impedance change in SST Magnifier



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

Hi John,

I don't know of any natuaral reason for this.  I would suspect something in
the electronics is doing something strange.  Perhaps something is shorting.
 The streamer impedance should be fairly consistant as far as I know at
220kOhms in series with about 1pF per foot of arc length.  It's hard to
guess what may be going on without seeing it first hand, but I sure can't
think of anything that would cause this.  There is a chance you are hiting
some other natural resonance somewhere.

Cheers,

	Terry


At 09:51 AM 12/26/2001 -0500, you wrote:
>
>Hi everyone, Happy Holidays!!
>
>I have a question about an observed impedance change in the operation of my 
>soild state magnifier coil. While operating in CW and interrupt modes the 
>impedance of the coil was constant at Fres for various power input levels 
>below 3 Kwatts. I changed the drive transformer to increase the power to the 
>magnifier coil to about 3.7 Kwatts based on the previously measured 
>impedance.  Everything was as expected in CW operation, with the impedance 
>constant as with lower power levels.  However, when running the coil in 
>interrupt mode, at Fres, under certain conditions (ingterrupt duty cycle 
>about 30%, frequency 107 Hz)the impedance of the magnifier dropped to less 
>than half of what it was before, then slowly oscillated between the two 
>values at about one to 3 hertz.  At this low impedance level the controller 
>was pumping about 10 K watts peak into the magnifier, producing 24" arcs to 
>a hand held aluminum rod (see picture attached).  Does anyone have an 
>explanation as to what's happening, and has anyone else observed this?
>
>John Tomacic
>
>
>
>
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