[Prev][Next][Index][Thread]

Re: Initial run

In a message dated 97-01-06 00:48:36 EST, you write:

<< After more than a year of slowly gathering parts and assembling (and
 tearing down), my son and I fired up our first large coil today.  We got
 36" sparks with an input of 1.7 KVA.  The coil has a secondary with a
 diameter of 8" and is wound with 1000 turns of 20ga enameled copper
 wire.  Top capacitance is a 16"X4" spun aluminum toroid.  The primary
 has 10 turns of #4 ground wire in a saucer configuration spaced 1/2". 
 The capacitor is a 0.05 CP 20KV unit.  Power comes from a 10 KVA 14,400
 v pig with 240 volts input regulated with a Powerstat 1256D.  Current
 limiting is by a Century arc welder and 0.51 ohms of resistance in
 series.  We have a variable speed non-synchronous rotary gap with 12
 tungsten electrodes.  We also have 4 additional stationary gaps which we
 did not use during the initial testing.   Ground is made up of four 8'
 ground rods 8' apart tied together with 6" strips of copper roofing
 material.  Only three were in use for this test (just couldn't wait any
 longer)
 
 Conditions were not great for outdoor coiling today - winds gusting to
 over 20 mph and humidity very high.  All in all things went very well
 for the initial tests.  We'll work on higher inputs, fiddle with tuning
 and use some of the stationary gaps.  The secondary may be a bit
 over-coupled and we may have to raise it a bit - we are getting a few
 hits from the primary to the secondary.  No problems with interference
 on TVs or with any damage to solid state devices due to the use of 200
 amp line filters on each line in and out and with the use of a "double
 ground" system.
 
 Thanks to all on the list who have contributed to our education,
 especially Richard Quick who gave many helpful hints and Richard Hull's
 series of tapes.  We'll be continuing to improve on our system's
 performance.  Hope to get some pictures and videos tomorrow.  Will post
 when ready.
  >>


David,

Congratulations,  sounds like a great project.  Running a coil outside in the
wind is a problem.  I have had problems with my 6.0" coil running at 7 kva
outside with even minor wind. The wind disturbes the ion cloud around the
toroid and changes the frequency of the secondary, causing the coil to drift
in and out of tune.

You will want to use some static gaps in series with your rotary to get good
quenching and reduce the heat build up in the rotary.  You may also need to
put a strike ring around the outside of the primary, raised up just a bit.  I
have one and am having a problem with massive, sustained hits down to the
strike rail.  The 40" toroid has a raised ring all around the top outside
edge and it still likes to hit down toward the primary.

Ed Sonderman