A few quick questions....

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "by way of Terry Fritz <twftesla-at-uswest-dot-net>" <yevaud_new.uk-at-excite.co.uk>


Hi everyone -

I hope you can help with a few quick questions....

1. Variacs. My NST is a 10kV 100mA model run from the 230V UK mains.
Consequently I'm expecting that when the TC is operating the current drawn
from the mains will be 1000W/230V = 4.3 A and so am saving up to get a
variac rated at 8A (the nearest rating is 5A but I thought it might be wise
to get the next one up just in case....!). Now have I forgotten something or
is this estimate ok ? I'm sure I've seen a web-site in which someone was
using a similar size NST and yet was pulling currents from the wall much
larger than a simple application of P=IV would suggest....?

2. Power factor correction capacitors for the NST. It's a Tunewell
transformer and the makers suggest using a pfc cap of 40uF. Is it actually
worthwhile using a PFC in TC work.....if only to reduce the electricity
bills ?! 

3. Positioning of the NST. I'm thinking of putting the MMC etc under the
primary and secondary coils as in the most popular TC designs but was
wondering if there are any undesireable effects of having all this equipment
sitting in the magnetic field of the primary ? Particularly a huge lump of
soft iron in the form of the NST !  If the NST is under the coil so that the
mains leads run across the floor has anyone had a secondary strike the mains
leads ? At the moment I'm leaning towards having the NST and NST protection
filter at a distance from the coil and running the EHT leads across the
floor....

4. A question for Terry, I think: I'm thinking of using your multiple static
gap design (the one in which you have lots of short copper tubes fixed to a
wooden baseboard). Is that going to be ok for a 1kW coil run for short
periods or do I have to start thinking about cooling fans and perhaps the
TCBOR design ? How hot do the tubes get....I've visions of 3mm transparent
polystyrene sheet melting so I'm wondering what (cheap!) material for the
baseboard might do....un-copper clad matrix board...?

With thanks,

Alan.





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