Re: Carts

In a message dated 95-08-29 13:27:44 EDT, tesla-at-grendel.objinc-dot-com writes:

MC>Hi Ed,
ES>I don't know what voltage transformer you are using, but I had both of my
ES>capacitors fail when using them with 12kv neon sign transformers.  Are you
ES>planning to use them in series/parallel?  I would recommend that.  I think
ES>they will work with a good safety margin up to 15 to 18kv when two are
ES>in series.  You should run them for short periods for a few weeks
ES>increasing the voltage before going to full voltage.
MC>I have two 15kv 60 mA neon transformers that I will be using to power the
MC>beast. I plan to use my caps in series/parallel arrangement- I just hope
MC>heck that they dont blow. I made the caps using 1.5 mm (60 mil) thick
MC>polyethylene so technically they should be good for the voltage.


It sounds like you made the same capacitors that I did.  You should have
plenty of margin using two in series.  I ran mine that way for a couple of
weeks then blew the first one using 4  12kv 30ma neons and one capacitor.
 Then I removed that one and put in the last good one and tried to keep the
secondary voltage at 10kv max but must have exceeded it one day because I
eventually lost that one also.  My problem was I needed .02mfd and only built
two capacitors.  You are doing it the correct way to use two in series and in
parallel with two more that are in series.  You should have .02mfd at (my
estimate) about 18kv rating.
MC> Thanks for the advice on running them in gently - I will definitely do
MC>BTW- how did you blow your caps? I know you were trying to max out your
MC>do you reckon that you set your spark gaps too wide? Was it the same thing
MC>when your neons blew as well ( I sure dont want to blow my neons either- I
MC>couldnt find any old ones around so I bought 2 brand new imported Italian
MC>neons - they cost me about $150 US for the pair!)

The spark gap I was using at the time was the standard cylindrical gap as
outlined in the instructions that can be found at the ftp site.  Maybe it was
too much gap for one capacitor.

Two brand new neons - I am impressed - I have never even seen a new neon.
 The first neon I blew was a 12kv 60ma.  After I completed the capacitors,
one set of the construction plans suggested connecting the cap directly
across the output of a neon to "burn" it in.  This is a bad idea.  The neon
got very hot and lasted about 2 hours set at about 50% power.  Don't do this!
 The second neon I lost was a 12 kv 120ma (I was proud of this one).  It was
shorted when I got it.  I took it apart, removed all the tar, tested it and
it worked fine.  Then I made a nice plastic case for it and reassembled it.
 The first time I had it up to full power it lasted about 30 seconds and
cooked.  The third neon I lost was a 12kv 30 ma and I don't know why I lost
it.  I can tell you I spent more on neons than I did my pole pig and I don't
think I can kill this thing.  I still needed to go through the neon
experience.  I wouldn't recommed that anyone start out with only a pig for
ES>I use the same circuit you are describing - with the gap across the high
ES>voltage line and the capacitor in series with the primary.  I have had my
ES>safety gap fire at least a couple of times and would not personally run
ES>without it.
MC>Ok I will definitely be keeping the safety gap.
MC>Well things are finally starting to come together now- hopefully I will be
MC>producing spark (and not smoke from my caps or neon) in about a week or 2.
MC>(BTW Ed, I have to admit I am really impressed with how fast you have been
MC>making your Tesla coils- I still remember your first post from when you
MC>just starting to make your first Quick assisted neon power coil, and just
MC>few months later you are using pigs to power them!

I certainly couldn't have made the progress I did without Richard Quick's
help.  He has been invaluable.  I started the project in the winter when I
did not have anything else to do so I had a lot of time.  I also did build a
smaller Tesla coil in high school (about 30 years ago) - although I did not
know much about what I was doing.  It produced 12" sparks.

It sounds like you're having fun.  I would start with one neon, capacitors in
series and go easy with the power for a while.

Ed Sonderman
MC>Best Regards,