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Re: Primary Tap



 
----- Original Message ----- 
From: Tesla List 
To: tesla-at-pupman-dot-com 
Sent: Sunday, January 09, 2000 22:49
Subject: Primary Tap

Original Poster: "J. B. Weazle McCreath" <weazle-at-hurontel.on.ca> 


>Hello Coilers:

>What do you fellows with the higher powered coils use for making
>the tap connections to your primaries while tuning? 
 
John,
 
I use wimpy aligator clips on 18 guage wire! On my "big' coils I do an
instrument tune with an o-scope and sine wave signal generator.  I
determine the Fo of the secondary system and topload attached with the coil
in the firing location (to accomodate outside capacitance coupling
effects).  I then find the tune point on the primary system at a frequency
which is about 6% lower than the Fo of the secondary resonator.  This helps
put the tuning right under streamer loading during operation.  I then mark
the primary tap point with a piece of tape, disconnect and remove the test
apparatus (a safe distance away!), make the bolted high powered tap
connection and do a test run.  I've seldom had to re-position the tap
following this procedure.  It works well for me.
 
> On my new,
>higher powered coil, I found that even a good quality alligator
>clip wasn't making a solid enough connection and I had to use a
>copper clamp bolted in place.  This obviously slows the whole
>tuning process down.  Any suggestions?

If you insist on doing power tuning, on NST powered coils you can solder
some copper braid taken from RG-8 cable shield for example, into the jaws
of the alligator clip.  It flattens to make a much better connection than
the little teeth of the clip alone can. I think this idea was posted a
while back by Father Tom. I guess you could use this trick on battery
booster cable jaws with some wide heavy braid for systems operating in the
10 kVA regime.  They would attach fine to your #2 or #1 AWG flying welding
cable leads used in the tank circuit.  Remove all power before reaching in
and changing the tap position though! :)
Robert W. Stephens
Director
AREA31 Research Facility
www.area31-dot-org

>73, Weazle, VE3EAR/VE3WZL

>Listening: 147.030+ and 442.075+
>E-mail:    weazle-at-hurontel.on.ca
>           or ve3ear-at-rac.ca
>Web site:  www.hurontel.on.ca/~weazle