[Prev][Next][Index][Thread]
More Fun with Bottle Capacitors
rom: ghunter-at-mail.enterprise-dot-net [SMTP:ghunter-at-mail.enterprise-dot-net]
Sent: Tuesday, November 11, 1997 3:45 PM
To: Tesla List
Subject: More Fun with Bottle Capacitors
Did some more tests with 750ml wine bottle saltwater & foil caps.
Today I used a Fluke tabletop digital multimeter to do the current
measurements instead of the Fluke 87 pocket model.
With four bottle caps (two in series with two) I got a really
peculiar result. When I applied power to my 15kv/30ma neon xfmr, I
heard a loud snapping sound. To my amazement, I saw (& heard!) a
spark periodically jumping AROUND the standoff insulator to the case
of the neon! An incredible jump for 15kvac. I'm using the outdoor
model "Transco" xfmr with ribbed, ceramic HV terminals on each end.
The jump distance around the insulator to the case is probably a
couple of inches. I'd love to know how it was doing that. I got in
such a hurry to kill the power I forgot to measure the series
current.
In the next test, I ran six bottle caps--three in series with three.
The anomalous spark did not reappear. The Fluke meter said the
series current thru the caps was 32ma--max current for my neon.
Obviously, the bottle caps have even more capacitance than I
estimated earlier.
I ran the six caps for several minutes at 15kvac. They didn't fail.
I'm going to go with this "sixpack" configuration for my little 4.5"
x 23" coil and see how it does. I wish I had a real capacitance
meter. Maybe I'll build or buy one before I start my next coil
project. 15kv is more trouble than it's worth. My next neon will be
9 or 10kv -at- 60ma. I'll get more power with less voltage--much easier
on the caps! I've also got a matched pair of 900w microwave xfmrs.
These would make a robust low voltage/high current supply. I've
already started thinking about my 6" coil...
Greg