[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: [TCML] Pig SISG - Day 3





To help prevent those nasty pri strikes on high power coils try this:

Make up some stands that are approx 3 inches higher than your primary and
space them at 120 degrees around the coil.  I usually place mine approx 2
ft out away from the pri.  I make mine out of wood dowels and use a 14 AWG
wire running up the dowel to the top where I terminate it with a sewing
machine needle.  The 3 stands hook together at the bases with cheap
bananna plugs and receptacles.

This gives the stray sparks a definite strike point so they won't go near
your caps, etc.  It's cheap, easy, and works great.  Eliminates the
necessity for strike rails attached to the oscillator base.

Dr. Resonance



> Folks-
>
>     Well, I only had a little time after I got off work  before it got
> dark
> around here. So I only had time to check a few things before  running
> again
> tonight.
>     Once again, I decided "I gotta have more cowbell!"  So I added one of
> the
> Maxwell 37667's, for a total primary capacitance of .105  uF. To quote
> Richard Hull, "When we hear of a builder who uses more than .1 uF  of
> capacitance,
> we wonder about the builder." Well, it certainly ran better  with even
> more
> cap!  I had a friend over tonight who saw Nemesis run in its  heyday, and
> he said
> the little 6" coil on my driveway was more impressive - in  its own way.
>     It only ran for about a minute before it died  again. I forgot to put
> up
> the piece of sheet steel along the side of the primary  caps, and another
> nasty strike curved around and hit "down there" again. After  that,
> nothing. The
> current would peg, but there was no output. I didn't see any  obvious
> damage to
> any components. All the IGBT heatsinks were uniformly warm.  The rectifier
> was in one piece.
>     I put the stuff aside, and ran the X-ray  transformer into a Jacob's
> ladder for the audience. Then I decided to see if I  could get the 6" coil
> running
> again.
>     After a few tries, with an occasional faint corona,  it stopped
> pegging
> the meter at low variac settings, and started acting like it  was
> triggering at
> high voltage again. Then it started to run, but at only  partial power. So
> I
> shut it down, and checked the rectifier bridge. Sure enough,  another leg
> was
> blown to bits - it was like the solder joints had melted in  several
> places.
> The string of 40 diodes was now in five pieces!
>     So again I replaced the bad leg with another "bar"  rectifier from
> that
> AM radio station. And no more failures for the rest of the  night! Those
> HVCA
> pucks are looking more attractive... might be excessive RMS  current is
> the
> culprit?
>     Well, I didn't even bother tuning the thing with  the primary tap. And
> I
> still haven't played with the coupling. But the corona  was so bad from
> the
> strike ring to the secondary, that it started arcing from  the top third
> of the
> secondary to the opening in the strike ring. Mind you, I've  got a 2x10"
> toroid at the top of the secondary, and the 8x36 less than a foot  above
> that. The
> secondary arcs were so bad, it scorched the varnish cover, and  bubbled
> through in several points. At the worst spot, the varnish caught fire,
> the wire
> glowed halfway around the coil, and soot covered everything from that
> point up.
> One strike somehow lit up the entire top third of the secondary under  the
> varnish with spiderweb turn-to turn sparks! When I put out the flames, I
> figured
> everything was done for the night.
>     Then I remembered the recent thread here about the  futile, if not
> downright harmful, effects of running with a strike ring. So I  took mine
> off. Wow,
> what a tremendous help!
>     No more corona from the secondary! No more  secondary strikes! No more
> glowing secondary turns! And it barely stuttered when  it hit the primary!
> In
> fact, it just made some staccato blasts as the primary  arced
> turn-to-turn. Now
> I feel the only place I need a "lightning rod" is  *under* the primary so
> it
> doesn't hit components on the bottom!
>     I added several breakout points to the toroid. It  seemed to really
> like
> having the multiple breakout points, and in fact seemed to  run the same
> from
> three or four simultaneous breakouts as it did from one.  Probably that
> high
> BPS.
>     I noticed if I ran for about 5 minutes steady now,  the heatsinks
> actually got too hot to touch! It also seemed like the BPS started  to
> creep up, and
> the sparks started to get weaker. So I may be finally stressing  the
> IGBT's.
> OTOH, after it cools for five minutes, it starts back up again just  fine.
> A
> few fans might be all it needs. Now I just gotta find a muffin fan  that
> runs
> off 22,000 volts of unfiltered DC...
>     Maybe when I have time to run it again (in a coupla  days) I'll try it
> with .150 uF of primary cap, and then put some filtering on  the DC side
> for
> Scott Bogard's amusement. Anybody want to suggest how much  filter
> capacitance I
> should add?
>     Sparks must be bright - two of my neighbors who  were inside their
> homes
> thought I was doing some more welding!
>     Nobody complained about any kind of TV, radio, cell  phone, or
> computer
> interference. Only one digital camera out of four had a  difficult time  -
> and
> I'm not convinced that it was an interference  problem. But the SISG seems
> to
> run very "clean" compared to a normal spark  gap.
>
> -Phil LaBudde
> Center for the Advanced Study of Ballistic  Improbabilities
>
>
>
> **************Biggest Grammy Award surprises of all time on AOL Music.
> (http://music.aol.com/grammys/pictures/never-won-a-grammy?NCID=aolcmp003000000025
> 48)
> _______________________________________________
> Tesla mailing list
> Tesla@xxxxxxxxxxxxxx
> http://www.pupman.com/mailman/listinfo/tesla
>


Dr. Resonance

_______________________________________________
Tesla mailing list
Tesla@xxxxxxxxxxxxxx
http://www.pupman.com/mailman/listinfo/tesla