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Re: Thoughts about sync..



The number of gaps will depend largely on your voltage.  15K volts will be
able to
jump more gaps than 10K volts.  With the fan turned OFF test your coil to
see if
it will jump all 9 gaps easily.  If not try 8 gaps.  Then try 7 gaps.  More
gaps
will not always make it perform better.

Example.  Lets assume you decide to use 7 gaps. Turn on the fan slowly
increasing
the fan speed with the room lights turned OFF or turned DOWN.  As the fan speed
increases the spark output at the toroid will increase too.  As you continue to
increase the fan speed at some point the spark output will begin to get
shorter..
When you notice the sparks getting shorter slow the fan down again and stop it
where it operates best.  Notice the fan speed might be 50% for example.   Lets
assume your output is 20" sparks

If you use 8 gaps instead of 7 gaps you will have to reduce the fan speed
to get
maximum output. Lets assume your output is 19" sparks.

If you use 6 gaps instead of 7 gaps you will have to increase the fan speed
to get
maximum output.  Lets assume your output is 19.5" sparks.

6, 7 and 8 gaps are all very close to the same output, all you have to do it
adjust the fan speed to fine tune the gap.

I like to fine tune my coil for best performance.  The best way I have
found to do
this is by using a little trick I learned when working at a local radio
station 30
years ago.  We would power the transmitter down after hours and run it at
about 5%
power.  Then when your make adjustments you could see a very noticable
difference
in the output.  If you are running 100 watts and you make an adjustment that
increases power by 1 watt you can see it.  If your running 10,000. watts
and you
make the same 1 watt adjustment you will see it.

Power your coil down so the output sparks are only about 1 inch long.  Turn the
fan speed down on the spark gap at lower power settings.  Now make some
adjustments.  Change the coupling, change the primary tap, change the top load.
Make notes.  Its very important to make notes.  With the power setting in
the same
place, if the 1 inch sparks increase to 2 inches then when you turn the
coil up to
full power you should technically get sparks twice as long as before. If
your coil
was way out of adjustment to start with and you were getting only 12"
sparks from
a 15K30ma neon on a 4" coil you will probably get sparks some place in the
neighbor hood of 22" to 24".

Notice that all the parts in the system work together.  If you change one thing
you will have to change something else too.  If you change the top load you
will
have to change the primary tap and also the spark gap.  Every time you change
something it effect the entire system and then it all has to be re-adjusted for
maximum output.  Its fun to tweek out the coil to see what it will do but
after an
hour of making adjustments all you gain might be sparks that are only 1"
longer.
I am not fussy about my coil, if it makes 22" sparks and I know it can
produce 24"
sparks I am happy with 22" sparks.

Gary Weaver






Tesla List wrote:

> Original Poster: Parpp807-at-aol-dot-com
>
> In a message dated 3/5/00 5:28:12 AM Central Standard Time, tesla-at-pupman-dot-com
> writes:
>
> <<  I use a
>  variac to adjust the fan speed.  I use this on all my coils from 1.5"
> diameter
>  up to 10" diameter.>>
>
> Hi Gary,
> I have just completed a very nice Scot D. gap using 9 pcs of 1.5 inch copper
> sweat fittings. I use a Sears shop vac for the blower. I have managed to
> learn that
> I am probably blowing too much air (from the fan :-)) ), and using one or two
> gaps too many for my 1350 Watt bipolar.
>
> Would you please give a little more mechanical information on the fan size
> and operating speeds? How can I tell when there is too much air? Am I correct
> in
> assuming that the rate of air flow is purely an experimental, trial and
error,
> determination?
>
> Happy day,
> Ralph Zekelman