Re: [TCML] Safety gap firing - (JAVATC Questions)

[Mddeming@xxxxxxx]

In a message dated 4/20/08 11:09:21 P.M. Eastern Daylight Time,  
resonance@xxxxxxxxxxxx writes:

This  sounds like you don't have enough primary turns to bring it into  proper
resonance.  that's why building a "scrap wire" pri on slitted  cardboard with
perhaps 16-20 turns is very important and will allow you to  select a full
tuning range to find best resonance.

Personally, I  never use safety gaps --- no reason to.  The low cap value
caps will  conduct any high freq currents to ground and the varisters will
clip any  overpotentials directly to ground.  I use a modified form of the
Terry  filter and definitely include two small inductors which clip any input
high  freq spikes before going thru the Terry filter.  Also, I break  the
resistances up putting one before the caps to ground and one after the  caps
to ground.  I then just use 25 Watt resistors (two in series on  each leg).
With the high speed varisters there really is no need for any  type of safety
gap.

If you contact me off-list I can email you the  schematic.  It works good as
our commercial small coils in museums  runs 6 days per week, 2-3 shows per
day, year after year without  failure.

Another mistake many experimenters make is using my plans and  then they
start modifying things.  The plans I send out work 100% all  the time --- as
long as you don't go off and start modifying things.   Then, you go out on a
limb where ferro-resonances and other interesting  things such as
constructive-destructive interference occurs, reflected  waves, etc, etc.
Many people will modify the sparkgap from what I  recommend, and this can
cause major performance changes in a small  coil.  Improper quenching and
improper coeff. of coupling are two  areas we test and research extensively
using expensive equipment to "see"  what is happening.  We adjust our designs
so problems do not  occur.  Modifying our design is asking for trouble unless
you have a  lot of test equipment to verify the outcome of any change.

Dr.  Resonance



Sounds like a good choice for the occasional user  who wants to show off his 
smoothly-running "Tesla Appliance" as a conversation  piece. And for many 
people, that is just what they want. Some may even like : 
_http://scientificsonline.com/product.asp?pn=3070301&cmss=tesla_ 
(http://scientificsonline.com/product.asp?pn=3070301&cmss=tesla)  ,  which is a table-top device with essentially 
"no user serviceable parts  inside" and requires no understanding.
    IMO, it is only when one starts playing "what if I  try changing..." in 
the real world, that things go wrong and understanding  begins. As an example, 
when my son was in high school, he made 9 modifications  to his Moped in the 
first six months he owned it, some of  which necessitated replacing the exhaust 
system twice.  My mother  drove various cars for 46 years without 
understanding how the ignition  switch "made the car go". while my son's Moped would top 
40 mph on a  straightaway. Both were quite satisfied.
 
Matt D.
 
 



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