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Re: status report, questions, etc.
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To: tesla@grendel.objinc.com, KLINEDA@univscvm.csd.scarolina.edu, QUANTUM@univscvm.csd.scarolina.edu, WMEYER@scientia.up.ac.za, bhaley@shore.net, frerichs@zfe.siemens.de, froula@cig.mot.com, haba@snakemail.hut.fi, jetter@ix.netcom.com, scott@csustan.csustan.edu
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Subject: Re: status report, questions, etc.
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From: Esondrmn@aol.com
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Date: Thu, 16 Nov 1995 12:27:14 -0500
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In a message dated 95-11-16 02:17:10 EST, tesla@grendel.objinc.com writes:
>Most (not all) CT's I've seen have the ratio somewhere on the unit. If
>that's the case, you really shouldn't have to "calibrate" anything. The
>transformation ratio is simply the current in to current out ratio (ex. - a
>200:1 CT that you're running 50A through would give you 50A/200 =
>250mA short-circuit current between the CT output terminals). In this
>example, you would use a 250mA full-scale AC ammeter to monitor up
>to 50A. You would then "calibrate" your ammeter by simply multiplying
>the values on the faceplate by 200. I imagine that you could put a
>known resistive load across the CT terminals to monitor the current
>indirectly from the voltage (V=IR), but just using an ammeter would be
>simpler and more direct (COMMENTS from anyone welcome?).
><<<
>I'm not trying to argue, just to understand...
>The CT has 400 turns, which would, I assume, give a 400:1 ratio.
>Why don't I just get a run away current if I use an ammeter? What's
limiting
>the current? Mark Barton suggests a burden load, which makes sense as an
>answer to me. I'll try things out, but I hope to understand things a little
>better, so the I can keep the smoke inside the meter. :-)
>
>Chip
Chip,
The above description is correct. A current transformer is made to be
connected directly to an AC ampmeter. I bought a surplus current transformer
and a surplus amp meter and then relabled the scale on the meter so it would
read correctly.
BTW, 50" of spark from a 4" coil is great. What is your input, 12kv at
120ma? If so, you are getting the same performance at that power level that
I got from my 6" coil - or better!
Ed Sonderman