Re: MOT power supply

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

Original poster: "Finn Hammer by way of Terry Fritz <twftesla-at-qwest-dot-net>" <f-h-at-c.dk>

Ted, all!

The data was supplied by Helmuth Singer, a German 2nd. hand instruments
trader.

http://www.helmut-singer.de/

The MOT`s in question were wound without bobbins, and the insulation to
the core was "MICA-like". That is the best I can describe it. It seemed
like a good porous material, which would be able to benefit from
saturation in oil.

The bobbin wound transformers will be able to get even more oil btwn
windings and core, so they are probably even better.

I used to have great doubts about the MOT`s to start with, but after
having run a 4-pack at length, and reading about the 6-packs, I now am a
fan of the concept.

A 2pack is a fine alternative to NST`s in a beginners system.

The only problem that I see, lies in the ballasting. The ballast should
preferably be air gapped, and about the same size as a single MOT.

One day, someone is going to have to pry a MOT open, remove the
secondary and install a second primary, and assemble the core again,
with an air gap in the 1/8 inch 3mm range, and measure the current
trough it at line voltage across it.

With primary windings in series.

This way the MOT project would be complete, and we could recommend the
construction of this kind of psu without guesswork.

Cheers, Finn Hammer

Tesla list skriver:
 >
 > Original poster: "tesla by way of Terry Fritz <twftesla-at-qwest-dot-net>" 
<tesla-at-paradise-dot-net.nz>
 >
 >  >Thanks for this data Finn this is ther very first time I have seen a real
 > rating for core to winding for a MOT.
 >
 > Still this figure is in air so in oil I'd imagine the stresses of a 4 or 6
 > pak could be indefinate. My oil as I recall is rated at 70kv/mm
 >
 > Whatever the limits are I think good design with 6 paks in oil does not pose
 > a problem from my own experience and judging from reports on the list.
 >
 > Hate to think of the ratio of dead NST's to MOT's or worse $NSTdead/$MOTdead
 > Best to all
 > Ted L in NZ
 >  > Typical insulation from winding to the core in a MOT is 7.5kV for 1
 >  > minute. It is only a question of how long they last.
 >  > This may well be adequate for coiling, and I encourage your attempts to
 >  > find the limit.