On Sun, Jul 25, 2010 at 19:06, Joe Mastroianni <joe@xxxxxxxxxxxxxx> wrote:
> That's a great question. Wonder if I could just slap a scope on it and get
> it to trigger/store on glitches...
>
> I'm also wondering - after all these years of coil making that people have
> done on this list - what's the best way to measure output power?
As far as I'm aware, not many people are concerned with "output power".
That's more of a concern if you're doing wireless power transmission.
> I mean, we have subjective streamer length. But I'm messing around
> between 240bps and 120bps and gap size and phase, etc. I can hear
> differences and see differences, but frankly, it's hard to really get
> anything quantitative without an actual side by side comparison.
Have you tried taking photos? That is the method I use, and it works quite
well for *quantitative* measurements. You just have to ensure that your
coil has something to hit every time, and then you can look at the photo and
find out where the streamer hit. Then all you have to do is measure where
the streamer hit to the breakout point.
> I run at 240 bps and then the exact same setup at 120 bps (by removing some
> electrodes) and I gotta say, at times they look the same - and maybe they
> are depending on how out of tune I am, etc.
>
> It would be nice if I could just measure and tune output power. I do the
> usual, wait for the safety gaps to fire and back off a little. But there
> are times I can have the variac on full power w/o the safeties firing
> (because the timing and tune are perfect) and then try the same
thing with a
> tiny difference, and pow. Safeties firing at 3/4 voltage.
>
Knowing the output power isn't going to help you tune the coil. The best
way is to tune until you get the longest sparks.
>
> So, this qualitative measurement stuff drives you toward lots of error
> prone trial and error. Maybe that's just "the way it's done", and frankly
> I'm ok with that if true (My wife says I must secretly wish my
coil is NEVER
> working right, so that I can keep twiddling with it.)
>
>
I generally compute the tune point using JavaTC and tune so that my primary
F0 is 14-15% lower than the secondary F0. If fine tuning is necessary, I'll
move the tap and test different points.
> But if there's a better way, I'd like to know. Like, I have some field
> strength meters. Perhaps I could set those up at some distance while
> running?
>
I think you'd want to have a scope measuring voltage and current going into
the spark channel to really measure output power on a sparking system. This
is quite difficult for obvious reasons. This doesn't really apply to SGTC,
but if you own a DRSSTC you can charge the bus capacitors up to normal
operating voltage and then remove the charging source. After the charging
source is removed from the bus you can enable the coil for one "pulse". The
resulting voltage on the bus will be lower than before. You take the
difference between the original bus voltage and resulting bus voltage and
plug that into the formula 1/2*C*V^2 to compute the energy consumed in one
"bang". This figure will include losses throughout the system, but provided
your system is not very lossy, most of the energy consumed will have gone
into the spark.
>
> Cheers,
> Joe
>
> On Jul 25, 2010, at 3:02 PM, Brandon Hendershot wrote:
>
> > I'd be really interested to find out exactly what's going on in these
> house wires that's wreaking all this havoc... Is there any sort of
> instrumentation or test equipment I could put in-between my coil and the
> outlet? Or is it as simple as a few amp/volt meters reading out?
> > Brandon
> >
> > On Jul 25, 2010, at 8:53 AM, Joe Mastroianni <joe@xxxxxxxxxxxxxx> wrote:
> >
> >> Hi Brandon
> >> When I ran my first coil - first light - I had the secondary, the strike
> ring, and the terry filter RF grounded to an 8' rod pounded into the earth.
> >> The Variac, of course, was grounded to the wall-socket 3rd prong. The
> line filter is grounded to the outlet 3rd prong. I had also connected the
> NST cases to the 3rd prong wall socket ground. (In fact, I've been running
> that way ever since.)
> >>
> >> But on my first run I had some difficulties with tuning - And several
> items on that same circuit suffered some sort of destructive forces. Most
> notably, I have a light fixture powered by a constant current LED driver I
> built myself. The output current adjusting resistor, which was a 2W deal,
> just simply "popped" wide open, in every respect - electrical and physical.
> >>
> >> That device was NOT grounded in any way. So whatever had killed it was
> running along either neutral or hot, because it's too far away physically
> from the coil to have suffered any RF or EMP or whatever you want to call
> the coil's electric field.
> >>
> >> I guess what I'm saying is that even with filters and safety gaps and
> ground rods and whatever I still had currents running through the house
> power.
> >> Lucky for me there's very little on that garage circuit to worry about
> (now that my LED driver is blown).
> >>
> >> I did fix the LED driver and am running it on the same circuit again.
> Call me daring or a fool - it hasn't had any issues since I've
been running
> properly tuned.
> >>
> >> Cheers,
> >> Joe
> >>
> >>
> >> On Jul 24, 2010, at 5:46 PM, Brandon Hendershot wrote:
> >>
> >>> Hi Gary,
> >>>
> >>> It's never done this before... Only when I attached the dummy load. Of
> course, I've never had the primary coil in place either... Shouldn't the
> Terry Filter prevent this kind of stuff?
> >>> And "midpoint ground", does that mean the ground connection on the case
> is wired to the midpoint of the secondary windings, Or am I mistaken?
> >>> And the computer is alive and well. I assume that beeping was a
> signifier of an internal GFI being tripped. Everything else on the circuit
> is fine...
> >>> Oh! Could it be that adding the coil on the wiring circuit was drawing
> too much power (a lot of power strips in use anyways) caused it? That seems
> a bit illogical though...
> >>> Thanks,
> >>> Brandon
> >>>
> >>> On Jul 24, 2010, at 4:45 PM, Gary Lau <glau1024@xxxxxxxxx> wrote:
> >>>
> >>>> I just noticed - you said your NST case is connected to the Variac
> green
> >>>> wire (mains safety ground). This is wrong, IMO. The NST case should
> be
> >>>> connected only to the RF ground, although there is some controversy
> here.
> >>>> But this still doesn't explain what zapped your PC.
> >>>>
> >>>> Regards, Gary Lau
> >>>> MA, USA
> >>>>
> >>>> On Sat, Jul 24, 2010 at 7:36 PM, Gary Lau <glau1024@xxxxxxxxx> wrote:
> >>>>
> >>>>> Oooo - not a good sign! I would have guessed that using the dummy
> load
> >>>>> would have been a more benign case than normal operation, since
> there's no
> >>>>> RF oscillations without a primary. I'm at a loss to suggest a fault
> >>>>> mechanism. Any possibility the primary circuit or dummy load could
> have
> >>>>> made contact with the mains? Is the PC still dead?
> >>>>>
> >>>>> Regards, Gary Lau
> >>>>> MA, USA
> >>>>>
> >>>>>
> >>>>> On Sat, Jul 24, 2010 at 5:59 PM, Brandon Hendershot <
> >>>>> brandonhendershot@xxxxxxxxx> wrote:
> >>>>>
> >>>>>> Hi All,
> >>>>>> Ran my coil the other day to test out that primary coil simulator I
> just
> >>>>>> recently made. It worked great! (Thanks again Gary) But when I shut
> it down
> >>>>>> and pulled my ear muffs off, I noticed my computer was making this
> loud
> >>>>>> solid "BEEEEEEEEEP" noise and wouldn't respond to keyboard or mouse
> input.
> >>>>>> What concerns me, is that the coil wasn't grounded at all except NST
> case
> >>>>>> to Variac to Green Wire Ground... Could it have interfered just
> through the
> >>>>>> mains power wires? My computer's only the next outlet down in the
> same
> >>>>>> circuit...
> >>>>>> All input appreciated here,
> >>>>>> Brandon
> >>>>>>
> >>>>>> Note: no safety gaps fired, nor were there any abnormalities...
> (arcing,
> >>>>>> smoke, etc.)
> >>>>>>
> >>>>>>
> >>>>>
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