Greetings Greg et al
Thanks for the note and appreciate the limitations re time and options to
respond.
If I have it correctly The core of the outer MOT will be at the potential of
the 2400 volt rms connection to the first MOT. This will place all the
voltage stress between that core and the 230v primary winding.
This may work well with the MOT in oil as this stuff has a dielectric
strength of 70kV /mm if I recall correctly (i.e. good dry xfrmr oil) A
better option IMHO is to lift the wire off the core of the outer MOT and
feed the first inner MOT into that. As I'm sure you recognise this will
distribute the voltage stress between the primary to core and the secondary
to core (note my thoughts about swamping stray capacity to equalise the
stress and the debate about earthing or not the core in this configuration)
I think you will be pleasantly surprised how well your configuration will
perform but at least if you do damage an outer MOT it is easily replaced and
an alternative configuration can be implemented. There are many
experimenters successfully running MOT secondary's in series (including me
with 3 in series) so it certainly works. My suspicion is you will find the
extra voltage it provides will be almost essential in getting the power thru
the coil that will provide the performance you can achieve with 3 phase
power. It would be cheaper to use a little more (and I think accessible with
your MOTs) voltage than look to make a bigger MMC. Your MMC configured for
56nF should hold off the voltage.
IMHO you will get more satisfactory and I think reliable if configured
correctly performance with a 2 in series MOT secondary arrangement than a
single MOT but time will tell
The pixs are great and they are showing us a really nice coil, good luck,
Ted in NZ
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-----Original Message----- From: Greg Peters Sent: Wednesday, November 27,
2013 10:43 AM To: Tesla Coil Mailing List Subject: Re: [TCML] DC Coil
progress. and housing MOT's
Hi Ted,
I dried the wood in the oven before I used it so hopefully it will be Ok. It
should only be a problem if the oil absorbs moisture which may allow it to
leech out the salts you mention. I can't imagine that anything soluble in
the oil itself would be particularly conductive.
I posted a few more coil pics yesterday. Unfortunately I only make time to
write posts on the bus so I don't elaborate too much. Feel free to ask any
specific questions.
I have some concerns about the MOTs holding up as I didn't remove the core
connection. I think they will be fine in parallel but series might be a
stretch.
Even in parallel I will still be charging the tank cap to over 11kV. This is
a tad lower than what I want, but it will still give me a few kW with
0.056uF. Or, I can run my mmc trays in parallel for over 0.2uF. Just not
sure if 8 caps in series would handle the current. Any thoughts anyone?
In fact, if the mmc held up I would probably rather go this way despite the
high gap losses.
Sent from my mobile.
<SNIPPED>
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