[Prev][Index][Thread]
No Rain=Test
Subject: No Rain=Test
Date: Sat, 31 May 1997 14:37:25 -0500
From: Chuck Curran <ccurran-at-execpc-dot-com>
To: Tesla List <tesla-at-pupman-dot-com>
Hello All:
We finally had a decent day here in south eastern Wisconsin and I was
able to run a successful test on my newest coil. I acutally got sparks
that were easily in the 12+ foot range, at 14 KW input. This is the
first real night with any type of success, so now the tuning will
start. I ran it four times about 1-2 minutes each time and ended up
with some of the neighbors out watching--they clapped at the end of the
runs!
I'll give the coil specs at the end, but I need to babble on for a bit
first. This was an all winter project and I was just blowing fuses the
first couple of runs, due to what turned out to be a faulty pilot light
holder, another long story. O.K., last night I set the coil up with a
breakout bump on the toroid, along with an aluminum ladder (grounded)
holding an aluminum handle extension for a paint roller for painting
ceilings. This provided a ground path with the end about 12' up and the
resulting strike distance of roughly six feet for the start. This
worked great and I then moved it out to eventually 11-12 feet which
still consistantly drew arcs along with the coil spitting out what
"seemed" to be longer sparks into free air and hits to the driveway
about every third or fourth spark (tough to count!) This story had to
be told today, otherwise it would be like a fish story--you know, the
fish gets bigger each time the fisherman tells the story! I am sure the
sparks were at least 12' long and I'm real excited about that.
On the fourth run, I was watching the meters and trying to generally
soak in anything out of the ordinary. I had inspected everything at the
end of the first short run and the spark gap wa humming real nice. Now
I suddenly saw some wisps of smoke or something coming from the
secondary. I shut it right down and found that 23" up from the bottom,
a turn or more (#15 wire) had gotten hot enough to bubble the Behr Super
Build 50 over coating and had really gotten it to smoke. I was having
so much fun I hadn't even tried to do any final tuning yet--I'm not real
sure yet why this occurred, but it will have to be resolved before any
more runs at full power are even considered.
I checked out the spark gap and both the new vacuum gap system and the
rotary built last year looked like the rotary loved it--no visible
problems there. However, the vacuum gap now in the daylight shows some
discoloration of the acrylic shell that holds the nine electrodes--that
needs a close look too. Absolutely no arcing was noticed anywhere, with
the primary now positioned about even to + 1/2" above the bottom primary
turn. If anyone has experienced a turn near the middle of the secondary
getting real hot, I'd appreciate any comments. Thanks in advance, coil
specs below.
Chuck Curran
Cedarburg, WI
Power Unit: 10 KVA 14,400 VAC pole pig, Fed by two Superior 1156D
autotransformers in parallel with current balancing choke. Fully
metered, with Century arc welder for current limiting and DC supply for
rotary gap motor. 50 amp breaker feeding power unit--it should have
popped!!
EMI Filtering: 60 amp EMI filter between power unit and wall connection
box.
Gap System: Vacuum stationary with American Science & Surplus 10 amp
120 VAC vacuum cleaner motor--uses nine 1" dia. by 3" long solid brass
electrodes with eight .025" air gaps. Rotary has 14" diameter 1/2 "
thick G-10 disk with 12 electrodes on 12" dia. bolt circle. Driven by 1
H.P. Carter 0-10,000 RPM universal motor, run at 2250 RPM for 450 BPS.
Dynamically balanced prior to use.
Toroid: 10 1/2" dia donut by 56" diameter made from aluminum flex duct
and aluminum foil covered 1" thick insulation sheet for center hub.
Duct covered in aluminum tape. Placed about 10" above top turn of
secondary. Used breakout bump during this run.
Secondary: 15 1/4" diameter by 55 3/4" long winding of #15 magnet
wire. (Note--magnet wire comes in 1/2 step increments, odd and even
sizes, if you work at a motor) manufacturing site like me. Form is PVC
sewer pipe with 1/2" thick walls
Primary: 5/8" diameter copper refrigeration tube, 21" I.D and 52" O.D.,
1/2" air gap between turns, 12 1/4 turns supported on acrylic plastic
forms.
Capacitors: One .05 mfd. -at- 30,000 VAC Plastic Capacitors cap in
parallel with one .025 mfd. -at- 20,000 VAC Condesner Productsl cap.
System Tune: Secondary & toroid resonant frequency is 64.78
Khz--primary was resonated at this point then 1/4 additional turn added
for expected drop during operation-must be in the ball-park!