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

Update


I thought I would post an update on my recent efforts.

Since I have had to move my coil out of the basement I haven't had it fired
up since last November.  We have had a serious winter this year (Washington
state).  I now store it in the garage and move it outside to fire it up.
 With the arrival of Spring, naturally my thoughts turn to getting the coil
fired up again.

I wanted to move the location of operation from the back yard to out in front
of the garage on the cement apron.  This will make moving it and setting
everything up much easier.  First I moved my 240 and 120 volt power outlets
from the back of the garage out to the front. Then I started on the new RF
ground system.  I drove three ground rods in with much sweat and anguish.
 When I got done, I could hardly move my hands or arms.  This is the third
ground system I have put in and it had better be the last.  Next I plan to
dig a trench between the three (they are in a triangle configuration 8.0 feet
apart) rods down about 1.5 feet.  Then I will solder galvanized steel
flashing to each rod, connecting all three.  Then I will cover everything
with water softner salt pellets and bury it all.  I will connect the ground
system to the coil with a three foot piece of flashing.  This should be the
best ground system I have built to date and will be located closest to the
coil.  All my other grounds have been about 20 feet away and connected to the
coil with # 6 AWG copper house ground wire.

I also completely disassembled all the spark gap, capacitor and primary
connections.  The rotary gap, cylindrical gap and capacitor are mounted on a
lower shelf below the coil on a roll around cart.  The lower shelf was about
thirty three inches below the platform the primary is mounted on and all the
interconnections were made with two pieces of RG213 in parallel.   I raised
the gaps up several inches and the capacitor up about 1.5 feet in an attempt
to shorten all the wiring.  Then I reconnected everything with 3/8 copper
tubing.  It was a fun job, kind of like plumbing with no water to leak when
you're done.  I am still not sure what to use for the moveable tap lead from
the capacitor to the primary.  I think I will use three pieces of RG213 in
parallel.  I hate for this to be the one low Q interconnection point.  What
is everyone else using for this??

When I had everything apart, I checked all the components of the gaps.  The
static gap looked somewhat cooked but I didn't see any maintenance needed.
 This gap is about one year old now.  The rotary was a different story.  The
fixed tungsten electrodes had been hot enough to melt the ends into balls.  I
reground nice clean radiused ends on them.  The stainless steel acorn nuts
used as contacts on the wheel have really taken some abuse.  They look like
hell.  I cleaned them up a bit and decided not to change them at this time.
 I have a whole box but they are expensive.  I reassembled everything and
reset the gaps to about .020" on each stationary electrode.  This is about as
tight as I could get it due to irrergularities in the acorn nut heights.
 When I first checked the gaps, they had burned themselfs open to about .050
or .060" on each side.

I hope all this will allow me to squeeze another foot or two of spark out of
this 6.0 inch coil.  I was up to about 73" with 7.5 to 8.0 KVA in.  I will
also measure the input voltage to the pig with the coil fired up and see if I
can rewire the Powerstat to raise the voltage.  It is a 14,400 volt pig with
240 volts in.  I am sure I have some voltage drop across the welder and oven
elements used as ballast.  I would like to get the input voltage dialed up to
250 volts so I am running at 15 KV in the primary.  This is the ratetd
voltage for my Condenser Products capacitor and I really don't want to exceed
this.

Ed Sonderman