Re: Another 942 run

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

Original poster: "Harold Weiss" <hweiss-at-new.rr-dot-com> 

Hi Dave,

On my controller I have an ammeter and voltmeter on the main variac output.
Non-PFCed, the current can range anywhere between 14-19 amps for the pair of
12/60s, depending on SRSG phasing.  During a run, the current will jump
around a bit.  The current will drop in the sweet spot as the phase control
is adjusted.

David E Weiss

 > Original poster: "Dave Kyle" <dave-at-kyleusa-dot-com>
 >
 > John,
 >
 > I am not the expert as others on this list are but your popping a 20 amp
 > breaker with a 12KV -at- 120 with PFC caps is suspicious to me. I had a
similar
 > experience with 15KV -at- 90 running a SRSG. My gap was about 90 degrees off
 > and caused me no end of blown 20 amp fuses until I corrected the timing.
It
 > was later determined that due to my odd timing the NSTs were saturating
and
 > drawing significantly higher currents than they would be normally limited.
 >
 > Note that the coil appeared to perform normally despite the dramatic
current
 > the NSTs were pulling. I was using Maxwell's and did not note any heating
of
 > the caps or primary but my runs were very very short owing to the fuses
 > blowing almost immediately; perhaps saving my caps and NSTs for another
day.
 >
 > Can you measure the line current while the coil is running? Compare that
to
 > the NST running a Jacob's ladder (non-inductive load). I bet if the
 > difference is substantial you have a SRSG phasing issue and if so maybe
this
 > is the reason for the excessively high currents on you caps.
 >
 > Dave
 >
 > =========================================
 > Dave Kyle
 > Austin, TX USA
 > Email: dave-at-kyleusa-dot-com
 >
 >
 > -----Original Message-----
 > From: Tesla list [mailto:tesla-at-pupman-dot-com]
 > Sent: Monday, March 08, 2004 9:56 PM
 > To: tesla-at-pupman-dot-com
 > Subject: Another 942 run
 >
 > Original poster: "John Richardson" <jprich-at-up-dot-net>
 >
 > Hello,
 >
 > I replaced the cap that blew yesterday, and reset all of my safety
 > gaps.  7/32 on the NST and 1/4 on the SRSG.  I think that I will set the
 > RSG a little tighter than the NST gap, because if the RSG gap doesn't
fire,
 > the NST gap will, popping the 20 amp breaker!  (Why?  Time to hook up my
 > Corcom?  Or is it because I don't have a dedicated RF ground?)  This is
 > with 300uf of PFC caps.  I did a quick alligator clip lash of of John's
 > phase controller, and with the 1/20 hp Teletype motor, about 50uf seems
the
 > best.  The voltage rise is about five volts above line voltage, or
 > 125.  Not sure if this matters.  75uf doesn't seem to make much more of a
 > difference than 50, except I get a lot more of a growl out of the
 > motor.  As I thought, the RSG phasing was pretty close before, but there
is
 > a subtle difference in output.  Zero inductance to about 25% variac travel
 > seems to be the sweetest spot, anything more and the safety gaps fire like
 > crazy.  Primary is still getting warm, but not hot like it did with the
 > last bad cap.  The dog is going ape with this thing running, so I did have
 > to keep runs short.  Caps are getting slightly warm.  Re-checked RSG
 > spacing, and the 5/32 tungstens are starting to erode.  Is this normal for
 > such a short run time?  This is my first foray into SRSGs, so I don't
 > know.  This weekend or later this week, I plan on running for an extended
 > period of time to check for tank heating and more caps popping.  I have
 > found one cap with the "sand size piece" under the first layer, per David
 > Weiss.  Will see if that one goes first.  One more thing:  Anyone running
 > their coils in a basement have some stray streamers up and hit the house
 > wiring?  It's not a good thing, but sometimes hard to avoid in close
 > quarters.  All of the incandescent bulbs in the room, maybe six or seven,
 > light up when a streamer hit the 12-2 light wiring.  Each bulb had the
 > equivalent intensity of about a 25 watt unit.  Pretty neat, albeit rather
 > unsafe.  Obvious the toroid is too small, as I can get 46-50 inchers and
 > still have multiple streamers coming off of other areas of the toroid.
 >
 > Thanks to all who are helping me.
 >
 > John Richardson
 >
 >