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Re: Rotaty popping, (Was Re: commercial cap failure)
Hi jon, Ed.
I noted to the list, last month about this same occurence.
Have you checked the firing point on the incoming wave form
in relation to your SRSG. If mine is at the wrong point, the thing
sounds like a 'dog' and I get continual 'backfires' across the
safety gap. Just changing the firing angle turns it into a pussy-cat.
Could it be that as you change the level of control inductance with
the welder, you are also shifting the phase of the waveform in
relation to the srsg firing point? - I bet the srsg motor supply is
not coming out of the welder - it's coming straight from the wall.
Any comments list?
Best Regards
Robin Copini.
Tesla List wrote:
> Original Poster: "Jon Rosenstiel" <jonr-at-pacbell-dot-net>
>
> <snip>
> >
> > If you had a safety gap across the cap, I would think that you did not
> kill
> > it with overvoltage. What is the gap width set to? What are you using
> for
> > ballast for the pole transformer? When I was having this problem, the
> sound
> > coming from the rotary was not nice and smooth, there was frequent odd
> noises
> > that sounded like small explosions or backfires - not exactly, but I don't
> > know how else to describe it. When I changed the ballast from the welder
> to
> > a large variac, this all went away.
> >
> > Ed Sonderman
> >
> >
>
> 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?