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Re: Measuring secondary c

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 Te> e> Message-ID: <9503311730.AA25776-at-grendel.objinc-dot-com>
 Te> Newsgroups: tesla.list

 Te> From Esondrmn-at-aol-dot-com Fri Mar 31 10:17 MST 1995
 >Received: from mail04.mail.aol-dot-com by ns-1.csn-dot-net with SMTP id AA13963
 Te> (5.65c/IDA-1.4.4 for <tesla-at-grendel.objinc-dot-com>); Fri, 31 Mar 1995
 Te> 10:08:34 -0700
 Te> Date: Fri, 31 Mar 1995 11:42:19 -0500
 Te> From: Esondrmn-at-aol-dot-com
 Te> To: tesla-at-grendel.objinc-dot-com
 Te> Subject: Measuring secondary current


 Te> Wes B,

 Te> Last night I wound a small pickup coil using a 1.5" dia plastic
 Te> toroid.  I wound about 70 turns of #26 insulated wire on it and ran the
 Te> main secondary ground wire through it.  Running the coil about one half
 Te> power (about 24" discharges) I still measure no voltage from the pickup
 Te> coil - even on the 5 volt AC scale.  I can't figure this out, I thought
 Te> there was a lot of current flowing in the ground wire.  Is this a
 Te> frequency response problem with my Simpson volt meter?

 Te> Thanks,  Ed Sonderman

 MG> Ed, at these frequencies you must use a suitable core, an air wound
 pickup coil, or one wound on an inapropriate core will not work. I have
 built current xformers that work very well at Tesla coil frequencies using
 a core from an TV set flyback transformer, these cores are good from about
 10 Khz to about 500 Khz.
  
  Start by removing all the original windings from the core, then wind about
 300 turns of #24-#26 wire on the core evenly. Then run your secondary
 ground lead through the center of the core to your ground system, then run
 the output of your current transformer to a bridge rectifier and a filter
 of about .01 ufd. (no higher) Then use your VOM on its D.C. scale to read
 the RELATIVE current level in the secondary base lead. These type of   
 transformers can be calibrated to a good degree of accuracy with a few
 simple pieces of equipment, if the group is interested, I'll go into greater
 detail and include a manner of calibration.


                                Mark Graalman
                                mark.graalman-at-mediccom.norden1-dot-com
                                compuserve 71612,1234

 


... Alias, Mark the spark
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