>> I was planning to use some combination of NST's
>> to get 12kV, 180 ma for resonant charging with the .04 mF cap but have been
>> reading lately about LTR caps and big caps, low bps and other conflicting
>> opinions i.e. small caps, high voltage. John Freau said that he had
>> previously posted on how to do something similar, I searched the archives
>> and no luck.
>> Any suggestions would be greatly appreciated
>> Michael Doyle - Lab Technician >>
>THe LTR caps with NST's are very good, but they won't work well
>with a static gap, a sync rotary is needed. Resonant caps can run at
>120 bps with a static gap, but the transformer may be destroyed
>because the gaps often need to be quite wide to give strong results.
>The technique I posted in the past is for use with a sync gap. I've
>since changed the writeup to include LTR operation. My set up is for
>obtaining the absolute max performance from an NST. Folks often
>prefer to to push a system less vigorously.
I have to disagree with the suggestion that LTR caps don't work well with
static gaps. All long I have been using a .01 uF cap with my 15KV/60mA
NST and static gap, and this was exactly mains-resonant, giving very
satisfactory 51" sparks. I just tried paralleling my .012uF MMC cap with
my .01uF Fair Radio Sales cap. I'm now getting 58" sparks with the
.022uF combo. Can't complain about that!
One further thing of interest here. The reason I migrated from the FRS
caap to an MMC was that the FRS cap became warm. With the two in
parallel, that is no longer the case. This isn't too surprising due to
the no doubt lower BPS occuring with the larger cap, but it does show
that the FRS caps can be made to work reliably.
Regards, Gary Lau
Waltham, MA USA