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Re: Rotaty popping, (Was Re: commercial cap failure)

In a message dated 4/22/00 10:23:53 PM Pacific Daylight Time, 
tesla@pupman.com writes:

<< 
 Ed,
 Jon Rosenstiel here. We corresponded a few times via email, ( Re:
 Sonderman's Saga). Your above comment in regards to explosions or backfires
 in the rotary made a light go on. With my system, (6" x 28" secondary, 5kVA
 14400V pig and 120bps srsg), I notice every once in a while, (particularly
 above 230Vac in), a sound like a car door slamming shut. I usually shut down
 and check for visitors, but never find any!
 Other than the infrequent car door slamming sound my coil runs fine, always
 nice and smooth, but  I have this nagging feeling  that something's not
 quite right. I think that I'm getting too much "inductive kick" from my
 welder ballast. The reason's that I think I'm getting too much "kick" is
 that:
 1. Any amount of parallel resistive ballast kills coil performance.
 2. Coil performance is better with the welder on "low" range. Let me
 explain; The welder that I'm using for ballast is a old Sears 185A model
 that has a low and high current socket on the front panel, (along with the
 variable inductance core).  I would think that I would be able to input more
 current, (and get longer sparks), using the high range socket. This is what
 happens when a Jacobs ladder is connected.  I figured the same would happen
 with my coil connected. It doesn't. My coil has best output on low range.
 When I select high range the input current stays the same and to get the
 same sparks I have to turn up the input voltage.
 
 I think that next time I run my coil I'll install a safety gap across the
 srsg and observe the firing of the safety gap while trying, 1:Parallel
 resistive ballast, and 2:Low and high range on the inductive ballast,
 (welder). I think that if I'm getting a lot of "inductive kick" the safety
 gap across the srsg will fire easier, (or more often).
 
  I will also try to watch the srsg closer to see if I can see any flashes of
 light associated with the "car door slamming" sound.  With 6' sparks flying
 around it's pretty hard concentrate solely on the gap. Maybe I need to have
 my coiling buddy come over so there are two of us to observe things.
 
 I'm chicken to wire the safety gap across the cap because when I once did
 the cap failed just as the safety fired.
 Maybe a coincidence, but I'm not pushing my luck!
 
 Regards,
 Jon
 
 PS: What is the current rating of your current control variac? 28A? Or
 larger?
  >>
Jon,

It sounds like our two systems are very much alike except that you are using 
a synchronous gap.  It does sound like your welder ballast is causing some 
strange problems.  I got lucky on the variac that I am now using for ballast. 
 I found it at a used electrical supply place.  It is a 5,000 watt 120 volt 
variac used for controlling high power lighting in theaters (I believe).  It 
should be good for 40 amps.  I had to put new brushes in it - which cost me 
more than the unit itself.  I did smoke the new brushes once by adjusting the 
variac when the coil was running at full power.  I still use some resistance 
in series with the ballast.

What size toroid(s) are you using.  What size primary cap?  I use two 
toroids, one 33" and one 44" in diameter.  I use two C.P. commercial caps of 
.025 uf in parallel.

I agree on the safety gap, it belongs across the rotary gap.

Ed Sonderman