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Re: Fired, but need help
Hello Patti,
It sounds like your coil is being overdriven (overcoupled) very seriously. You
are getting a good output, tho. You will have to correct this, otherwise your
secondary will burn up. The points where multiple waves are meeting (forming
the sparks you are seeing) get very hot.
You have three ways to change the coupling:
a.) Raise the secondary up higher
b.) Make a flat or conical primary. They couple less.
c.) Adjust your tap on your primary turn (This would be the least desirable)
BTW: Go for a higher H/D ratio on your next coil. The ratio is too low for
high power coils. I would go for a 4 or 4.5er ratio for the power you are
pumping in. This will reduce your number of strikes to the ground rail.
Coiler greets from germany,
Reinhard
Original Poster: "Patti" <asrai-at-palmnet-dot-net>
Hello Listers,
This weekend the weather held out so I was finally able to achieve first
light. Results after safety gap, RSG, secondary height and toroid
adjustments was 68" to a ground rod suspended on a ladder. I did have a
number of strike rail hits, so I raised the toroid up to a height of 18"
above the top of the secondary. My final voltage was about 196 VAC at 22
amps to the 10KVA 14.4kv pole transformer that is current limited by a
variable inductor with a range of .68 MH to 8.9 MH (setting was 6.9) and 2.9
ohms of 10kw heater elements in series.
One problem though, and I need some help.
I'm getting numerous strikes along the outside of the secondary, starting
with the top winding to the bottom winding. Also I suffered some damage two
turns about 5 inches up from the bottom of the secondary. It got a bit
cooked. Right now I have the secondary bottom winding sitting about 1.25
inches above the primary. I'm running safety gaps at the caps at 1/2 inch
and 5/16 inch on each side of the ground post tied to RF ground for the pole
transformer. The specs are:
Capacitor: 2 .22mf 50KVDC csi caps in a series for .11mf total
Toroid: 48" x 12" Aluminum duct wrapped with aluminum tape 53 pf
Primary: 100ft of 1/2 diam. copper tubing starting at 7.3125 inch radius
and ending with 19.8125 on turn #15. Spacing between turns is .250 inches.
Lpri needed for cap and toroid 50.8uh. Currently tapped at about 8.5 turns.
Secondary: 1000 turns of 22 AWG magnet wire wound on a 10.5 inch PVC duct
that was coated with .125 inches of polyurethane before winding for a total
winding length of 32 inches. wire measures .032 in diam. Coated with 1/16"
of polyurethane.
C=16.5 pf Lsec+ 80.5 mh
Resonance frequency of secondary with toroid installed: 67.3 Khz Without
toroid: 138.3 Khz
H/D ratio: 3.0 to 1
Used Medhurst constant of .61
I've worked the calculations using the formulas from the archives, other
list memeber's web pages and Wintesla program to make sure I'm getting
approximatly the same results. Any help would be appreciated especially on
fixing secondaries and how to stop the cookage.
Patti