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

status report, questions, etc.

Greetings all,

Last weekend was successful in the coiling area.  On Saturday I found a great
electronics store with lots of old junk.  I picked up a flexiformer and a 
cabinet for my power supply that I am starting to build.  The flexiformer 
is some sort of packaged transformer primary (their words).  It can be used
as a current transformer, which is why I bought it.  This leads me to my first
question:

How does one use and calibrate a current transformer?  More specifically, 
I know that you put one of the output (220V) leads through the hole, and 
then connect an ammeter across the output leads, but why would the current
be limited?  I thought non-current-limiting transformers would produce as
much current as the load can draw.  Since ammeters are low in resistance,
wouldn't this short out the meter?  Also, since there are 400 turns in the
current transformer, would I get a 400:1 transformation in voltage?  This would
be 88kV.  Also, how would I calibrate the current transformer?  Should I 
just use ohms law and a big resistor or a few light bulbs?

So on Sunday a friend came over and we played with the new vacuum cleaner
gap and tried to get it to work.  After some investigation, we think we found
out why it didn't.  It turns out that the arc between the copper pipes would
zap along the plexiglass at the end of the pipe.  This carbonized the plexi
and made it conductive, which wrecked the quenching.  I am going to put some
tiles at the ends of the pipe to stop the burning of the plexiglass.  I'll
report when I finally get it working.

With this failure, we tried the compressed air gap.  It worked well, so we
tried backing off the electrodes.   After a while, we had about 3/4" gap 
between the electrodes and were getting 50" sparks!  As we backed off the 
electrodes, we had to back off the saftey gap too.  This caused one of
my 30ma xformers to short out.  Oddly enough,  it didn't affect the spark
length.  This indicates to me that I can go further.

Next question:  Would a rotary gap help increase spark length?  I plan on
building one anyway, since I recently got a pole pig :-).

I'll post photos if they came out, as soon as the film is used up and
developed.

Chip