Yesterday, Monday, I operated from GB2CPM, not on LF but at the HF
permanent amateur station that forms part of the radio section of the museum.
At the Electricity Hall a group of Telso Coil builders had converged
for a Telsa coil session. This comprised two groups, an indoor
exibition using small coils ranging from 10cm long to 1m long; and
the second group with the big coils (up to 2m long) which had to be
done outside because of the very high voltages they produced.
The indoor goup had the advantage having a large room that could be
darkened allowing the spectacular display to bee seen to its best
advantage. The room had to be ventilated between sessions to clear
out all the ozone!
The outdoor group set up a test area in the afternoon, starting by
digging a cruciform shaped trench and laying down a lot of copper
tubing and soaking it in brine before filling it in. The components
of three large coils arrived in special vans and I was able to watch
and photograph these coils and the electrical control and power
systems being assembled.
The length of the main coils of the larger Telsa machines ranged from
1 to 2m with a length/diameter ratio of around 3:1. The inductance of
the main coils ranged from 400mH to 1.2H depending on the size of the
machine. All coils seemed to be close wound with 1mm enamelled copper
wire. The primary coils were made of 10mm copper tubing with clip
connections for 'tuning'.
This main set of experiments had to be done after the museum had
closed to the public and when it was getting dark. The corona
discharge from 1meV machine was truely spectacular and made our hair
stand on end!
I was much taken with the technology of these machines, particularly
the care with which the coils had been wound and the construction of
high capacity high voltage capacitors. Some members of the group were
interested in our activities in a similar technology.
If you want to know more about the Telsa Builders activities see
<www.tcbouk.org.uk>
--
Regards, Peter, G3LDO
<[email protected]>
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