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parallel secondary coil
From: gweaver[SMTP:gweaver-at-earthlink-dot-net]
Sent: Friday, October 24, 1997 3:33 PM
To: Tesla-at-pupman-dot-com
Subject: parallel secondary coil
I connected 3 secondary coils in parallel and found they perform just as
well as one large diameter secondary coil, with some advantages.
My primary coil is 6.5" ID. x 23" OD. 30 degrees 3/8" copper 3/8" spacing.
Power supply is 15K 50 ma unpotted neon in HV oil with a variac.
Cap is .00635 uf rolled poly HV oil filled.
Variable speed vacuum fan spark gap is 8 gaps .025 each gap.
Chokes are 40 turns of #14 solid copper with vinyl insulation on a ferrite
donut.
All 3 secondary coils are 4.5" dia. x 13"long, 602 turns of #24 wire.
I placed a 12" diameter circle shape of plywood in the center of the primary
to hold up the secondary coils.
I tried each secondary coil one at a time to make sure each coil operated
the same. I can't turn the power up all the way because the secondary coil
is so short the sparks are striking the primary coil and strike rail. Using
a 5" x 16" toriod on one coil the output sparks are 21" long to a ground
target with the variac set at 80..
I set 2 secondary coils on the plywood. The 2 coils are 1" apart. The
ground end of the secondary coils are connected to the ground wire. I
tested it on low power and the 2 coils arc to each other. With the 5" x 16"
toriod the output sparks are 22" to the ground target with the variac set at 80.
Next I put all 3 coils on the 12" plywood circle spaced 1" apart. With all
3 ground ends connected to the ground wire and no toroid the 3 coils arc to
each other. With the 5" x 16" toroid the output sparks are 21" with the
variac set on 80.
Its interesting that the 3 coils all arc to each other at the top with no
toriod. The coils are all exactly the same. Resonance frequency is the
same and they should all be in phase with each other.
When I changed from 1 secondary coil to 2 secondary coils in parallel it
changed the primary tap from turn 8 to turn 6. When I added the 3rd
secondary coil in parallel with the other 2 it changed the primary tap again.
I test indicates that it is possible to build a large TC using several
secondary coils in parallel instead of 1 large diameter secondary coil.
Smaller wire can be used for each small coil. Each small coil will be much
easier to handle than one large heavy coil. Winding each small coil will be
easier than winding a large coil. Arc over spacing is adjustable. Ratio is
adjustable.
Another interesting thing is the coil ratio. Using 4 coils all 4.5" dia x
36" long wound with #24 wire spaced so the outside diameter of the 4 coils
are 12" gives a ratio of 12 to 36 which equals 3:1. The ratio can be
adjusted by moving the secondary coils IN or OUT. The arc over spacing
between the primary and secondary coils can be adjusted by moving the
secondary coils away from the primary.
6 coils on 4" PVC pipe 4.5" dia. x 42" long spaced so the outside diameter
is 14" gives a ratio of 3:1.
4 coils on 6" PVC pipe 6.5" dia. x 42" long spaced so the outside diameter
is 14" gives a ratio of 3:1.
Gary Weaver