Re: Please Help! Trying to tune the primary coil (fwd)

["Tesla list" <tesla@xxxxxxxxxx>]

Moderated and approved by: Gerry Reynolds <greynolds@xxxxxxxxxx>



---------- Forwarded message ----------
Date: Sun, 24 Dec 2006 16:31:23 -0700
From: Terrell Fritz <terrellfone@xxxxxxxxxxxxxxxxxxxxxxx>
To: Tesla list <tesla@xxxxxxxxxx>
Subject: Re: Please Help!  Trying to tune the primary coil (fwd)

Hi Chris,

See the measurements section of this site:

http://myweb.tiscali.co.uk/teslatutorial/index.htm

http://myweb.tiscali.co.uk/teslatutorial/MEASUREMENTS.htm

Cheers,

         Terry



At 06:06 AM 12/24/2006, you wrote:
>Moderated and approved by: Gerry Reynolds <greynolds@xxxxxxxxxx>
>
>
>
>---------- Forwarded message ----------
>Date: Sun, 24 Dec 2006 20:34:19 +0800
>From: westland <westland@xxxxxx>
>To: Tesla list <tesla@xxxxxxxxxx>
>Subject: Please Help!  Trying to tune the primary coil
>
>Hi All:
>
>I've gotten to the stage where I need to tune my primary tap point, and
>I've run into a problem in trying to figure out how to wire up the
>primary coil to find the resonant frequency.    I initially pulled the
>secondary, put it on a plastic base, injected RF from my signal
>generator, and read the response off of my oscilloscope with a small
>antenna set as the input feed.  This worked well, and gave me a resonant
>frequency of 205KHz for a 4" x 22" coil with a 5x16 toroid topload.
>Here are pictures of the setup (sorry for the fuzzy initial picture)
>
>Secondary tuning setup 
>Antenna:    http://www.flickr.com/photos/51115445@N00/331719458/
>
>Secondary base (so it doesn't fall over when 
>measuring):  http://www.flickr.com/photos/51115445@N00/331719464/
>
>Secondary tuning setup:
>http://www.flickr.com/photos/51115445@N00/331719457/
>
>********
>
>So far so good.  So I hooked up the primary and the MMC (which I had
>tapped for 10.2 nF... see pic).  But I couldn't figure out how to wire
>up the tank circuit so that I could get a reading off my oscilloscope of
>the response to the injected RF signal (I tried several configurations,
>plumbing the Internet for sources, but couldn't get anything to work ...
>my voltage rises were all in the over 1 MHz area).
>
>I decided to compute from readings off my RLC meter, and found that I
>needed to tap near the end of my 14th winding (with the 10.2 nF cap) to
>get a resonance of 205K.  But even with this setup, I couldn't get the
>scope to give me any readings at all in the low kilohertz rang.  Here
>are more pictures of the setup.  I also tried to test the complete coil,
>but that didn't work either.
>
>Measuring impedance of 
>MMC:  http://www.flickr.com/photos/51115445@N00/331719460/
>
>Trying to measure resonance of primary 
>coil:  http://www.flickr.com/photos/51115445@N00/331719462/
>
>Measurements for complete Tesla 
>coil:  http://www.flickr.com/photos/51115445@N00/331719463/
>
>
>
>Can anyone give me advice on where I am making my mistakes here.  From the 
>descriptions I've read on the Internet, tuning the primary should be 
>straightforward (but no one tells you how to wire up the test setup).  You 
>are looking for two peaks with a valley at the secondary resonance 
>(indicating the secondary is drawing power away from the primary circuit)
>
>Thanks in advance for the help
>
>Chris Westland
>
>
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>
>--
>____________________________________________________
>
>J. Christopher Westland, PhD CPA
>Professor, ISMT, University of Science & Technology, HK Clearwater 
>Bay,Kowloon, Hong Kong
>Tel: 852 2358 7643
>Fax: 852 2358 2421
>Mob: 852 9528 1745
>URL: ihome.ust.hk/~westland
>Mobile e-mail: chris.westland@xxxxxxxxxxxx