Re: Why people don't use MOTs in a TC

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

Original poster: "Jason Johnson by way of Terry Fritz <twftesla-at-qwest-dot-net>" <hvjjohnson13-at-hotmail-dot-com>

I don't see that oil can penetrate the
> impregnate of the secondary coil, but I believe that coil can
completely
> penetrate the primary, adding substantial insulation.

In my experience, the oil has no problem penetrating both windings, all
the way through. The only MOT I ever lost in service, I took apart and
ended up cutting through the secondary with a hacksaw, and there was
really quite a bit of oil in there. I could get quite a bit to squeeze
out from even the very center of the windings. The primary coil was also
saturated, and though I never cut it in half, it still oozes oil over a
year later. It makes quite a mess.

Oil should also do
> wonders in preventing external arcing, especially very clean and
moisture
> free oil.

Well what you said was probably the exact opposite of my oil. I use the
cheapest motor oil I could find, which is now about two years old, and
it has got polyureathane varnish in it, water, sawdust, carbon, dirt and
dust. It seems to perform just fine. As always YMMV.

>
> Also I think that insulation materials can be underestimated.

Definately. Manufacturers have to make very sure that the HV doesn't get
back into the LV side even under the very worst case scenarios. And
there is at least 4KV on a 2KV MOT that could get back into the 120 volt
side, due to the doubler circuit in the microwave. So they insulate
against at least this much, and alot of manufacturers have a safety
factor of 2 when it comes to this kind of stuff, just to avoid lawsuits.
So probably most MOTs could take 8KV without breakdown dry. And I say
this conservatively, because I have put a 12KV NST across a floating
secondary coil and core of one my MOTs w/o oil, just to see if it would
handle it, which it did just fine. It still works great.

 One time I
> brought together two leads of magnet wire connected to a 10kV NST. I
was
> surprised that no arc formed between the leads and I feared that the
NST had
> gone dead. Then I realized that the enamel on the magnet wire was hold
off
> the 10kV!
>

I believe this, but I wouldn't trust enamel insulation as HV wire
wherever there is a possibility of coming in contact with it.


<< Jason R. Johnson >>
G-3 #1129
The Geek Group
http://www.thegeekgroup-dot-org/

"The two most common elements in the universe are hydrogen and
stupidity."
 -Albert Einstein