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Magnifier #13 and a small coil.
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From: richard hull [SMTP:rhull-at-richmond.infi-dot-net]
Sent: Sunday, March 01, 1998 7:49 AM
To: tesla-at-pupman-dot-com
Subject: Magnifier #13 and a small coil.
MAGNIFIER #13 :
Taking a short sabbatical from my ongoing fusor work, I have assembled
TCBOR magnifier #13. I continues the down sizing tradition starded with
magnifier #12 and is just slightly larger than its predecessor. It
incoporates most of the features which were needed on maggey #12.
The driver, (which is how we number magnifiers), is unique in that the
primary is wound directly onto the secondary driver form directly over the
secondary turns.
The coupling has, thus, increased from the K=.5 of magnifier 12, to K=.73
(average depending on tap point) in magnifier #13.
Here are the driver specs.
16.5" OD PVC form 6" tall. (barely table top) It is wound with 43 turns of
#14 TW insulated wire. The top turn is a 7/8" diameter split ring of copper
tubing and acts as a corona ring. The resultant secondary inductance is
900uh If the coil is viewed as a standalone resonator it resonates at
1200khz (1.2mhz). It has a DC resistance of .37 ohms. It is held up 1.5"
off of the table by three PVC 1.5" pipe sections glued to the base. On of
these contains a bananna plug for the ground input to the base of the
secondary driver coil.
Over the secondary is wraped 7 turns of 6" wide 10 mil polyethylene sheeting
to cover the entire length of the secondary winding. A final smooth finish
winding of 2 turns of 6" wide 20 mil poly completes the secondary.
The primary is made up of 12 tight wound turns of #8 stranded ATW insulated
wire starting at the base and moving upward to a height of 2.5" from the
base. The top turn is allowed to feed off of the primary out 24" and ends
with a crimped lug. This leaves the top primary turn fully insulated and
unterminated on the driver.
Taps begin 5 turns down from the top turn and as you decend are 23, 32, 41,
52, 64, 75 and 89 uh respectively. This method of taking the top insulated
turn off to the tank circuit and taping down on the primary instead of up is
a feature used in all magnifiers since maggey #4.
Crude first tests were made with regular series static gaps and do not
optimize the system at all. A 7.5 KV transformer of 60ma was used and a .01
ufd tank capacitor was ultilized. the series gap system consisted of a 4
gap TCBOR cylinder vacuum gap plus a series magnetic blowout gap of TCBOR
design.
The resonator was chosen from about 20 resonators kept on hand for such
tests. It was an 8"X8" unit of 453 khz resonant frequency. Terminal
loading consisted of a 12X3 toroid and a step cone to a 14" hemispherical
terminal. The resonator system resonance now plunged to ~200 Khz.
The firing of the system showed about 390VA on the metering. A 5ufd optimal
PF correction cap was added and the meters indicated 300VA.
The system would produce occasional arcs to a grounded ball 25" away. A
continuous, unremiting, flaming white hot arc was drawn at 16". The driver
corona produced a 1" drawn arc to ground when so tested. This arc was of
blazing white intensity which produced an incredible sound which rattled the
nerves.
All in all not a bad test for a first pass.
The system is to be used with a new hydrogen thyratron driver system which
is to be assembled especially for it.
A SMALL COIL:
I have long worked with efficient little two coil systems. I have demoed
them to the amusement and amazement of many at the Teslathons here. The
latest is based on just how much arc one can extract from a small amount of
energy.
The transformer used was a 3KV 30ma neon unit. I power factor optimized it
with a 1.2mfd capacitor when in operation. The capacitor in the tank was a
.0033ufd unit made up from three.01 2KVDC micamold capacitors in series.
The gap was a 12 gap series static gap with machine ground tungsten points
(.0125" diameter) set for .002" gap each. A Variac controlled the input
voltage. An AC RMS wattmeter (0-100 watts full scale) was hooked in the
circuit, but was read as volt-amps.
The primary was a coned archemedian spiral of flat band (aluminum), the
resonaotr was a 3"X7" tall unit wound with #28 wire. It resonated unloaded
at 800Khz. I loaded it with a 10"X3" spun aluminum toroid. the new
resonance was 510 Khz.
When tuned and fired in the circuit above, I got 7.8" of arc to a 2" round
grounded ball. This was with 48 volts in from the variac and the watt meter
read 28 VA. The secret was to take the variac up to where the gap fired
and then advance it to the point where I got the maximum number of firings
per half cycle (3-4), and no further. This occured at 48 volts into the
transformer primary.
Pretty stunning performance. I was able to light a neon tube of 3 feet
length over 4 feet away from the unbreaking out system. Fluoresent tubes
would stay lit a little bit farther away. This is the best small system I
have ever assembled.
Richard Hull, TCBOR