Re: VERY HIGH BPS at 6kw!

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "colin.heath4 by way of Terry Fritz <teslalist-at-qwest-dot-net>" <colin.heath4-at-ntlworld-dot-com>

hi
i think 9' from a 47nF cap is going to be very dificult indeed if at all
possible in a two coil system unless you are going to up the voltage
cheers
colin

----- Original Message -----
From: Tesla list <tesla-at-pupman-dot-com>
To: <tesla-at-pupman-dot-com>
Sent: Friday, May 09, 2003 5:14 AM
Subject: Re: VERY HIGH BPS at 6kw!


 > Original poster: "Malcolm Watts by way of Terry Fritz
<teslalist-at-qwest-dot-net>" <m.j.watts-at-massey.ac.nz>
 >
 > Hi Steve,
 >
 > On 8 May 2003, at 21:46, Tesla list wrote:
 >
 >  > Original poster: "Steven Ward by way of Terry Fritz
 > <teslalist-at-qwest-dot-net>" <srward16-at-hotmail-dot-com>
 >  >
 >  > Hi all,
 >  >
 >  > I built a 4 pack MOT supply and it works ok.  There is no limiting
besides
 >  > the wires that come from the 240V outlet.  But thats not so
 >  > important.  This coil is running with a static sucker gap, and only
about
 >  > .0475uf of capacitance.  In this scenario, the arcs SCREAM!  It sounds
like
 >  > 1000bps or maybe more!  The sparks are WHITE and hot when the arc to
the
 >  > ground.  But, the coil is dissapointing with only 6-6.5 feet of
 >  > spark.  Also, the sparks will start downward, and end up vertical in
the
 >  > air!  This is common for high BPS i guess.
 >
 > It is common where there is effectively continuous heating of the air
 > channel.
 >
 >    But, i want about 9 feet or
 >  > more, so i need to lower the bps.  So, im thinking of making the cap in
the
 >  > .09 to .1uf range!  I know, this is HUGE.
 >
 > I wouldn't regard it as such. I've happily used caps of that size in
 > the past.
 >
 >    Right now, im using 13 turns on
 >  > the primary (7"ID  23"OD
 >  > .25" cu) with a 6.5"x36" 24awg secondary and a 4.5"x30" toroid.  I know
 >  > that with that huge cap, i will only use a small fraction of those
primary
 >  > turns.  But, just how BAD is this scenario?  Im basically limited to
9kv or
 >  > so.  I do plan to eventaully (if a 5 turn primary works good for
example)
 >  > make the primary from .5" copper or something bigger.  How bad will the
 >  > caps be stressed?  I have 3 strings of the geek type MMC caps, maybe 4
or 5
 >  > with the larger cap values (those nearing .1uf).  Are there any coils
 >  > similar to mine out there?  IF so, what is the typical output?  Id like
10
 >  > feet if possible.
 >
 > It is *not* the number of turns that count (how many times have I
 > said this before??) - it is the *inductance* that matters and if you
 > are concerned about very high primary currents and consequent gap
 > losses, then build a much lower frequency coil to get Xp (Lp) up. I
 > think your biggest problem is going to be a voltage limitation with
 > your relatively short secondary as Ep climbs.
 >
 > Malcolm
 >
 >
 >