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

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



---------- Forwarded message ----------
Date: Sun, 24 Dec 2006 23:13:47 -0300
From: Antonio Carlos M. de Queiroz <acmdq@xxxxxxxxxx>
To: Tesla list <tesla@xxxxxxxxxx>
Subject: Re: Please Help!  Trying to tune the primary coil (fwd)

Tesla list wrote:
> From: westland <westland@xxxxxx>
>
> 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)
>   
The method that I use is:
Connect a 1 Ohm resistor across the output of the signal generator, to 
have a low-impedance signal.
Connect the signal generator where the spark gap would be, with a 
low-frequency (1-10 kHz) square wave of maximum amplitude.
The secondary coil and top load shall be in place. Ground can be at the 
oscilloscope ground.
Look at the voltage over the primary capacitor, or over the primary 
inductor, at the transitions of the square wave.
Tune the system until you see full notches, like in this photo:
http://www.coe.ufrj.br/~acmq/tesla/tefpreg1.jpg

This is the ideal tuning without breakout. To account for streamer load, 
connect a wire to the top load with the length of a reasonable streamer 
and tune
in the same way. Mark the two positions found. The best point will be 
somewhere between these.
Note that the waveform shows also the resonance frequency of the two 
tanks, and allows the measurement of the coupling coefficient.

Antonio Carlos M. de Queiroz