Re: MOT stack rebuild

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: "Christoph Bohr" <cb@xxxxxxxxxxxxxxx>

Hello Paul.

Thanks for you offer, but since I live in germany
this would be too expensive.
Yesterday I took an 10MOhm resistance meter
and measured between pri/sec and each coil to core.
and could not observe even the smallest deflection
of the meter.... I guess even a light demage would have
left carbon that would show at least some resistive
path below 10MOhms ... at least I guess.
Wowever, using thicker wire on the primary side
won't do anything bad and I had a chance to
visually inspect the transformers.
Currently I fear I misinterpreted the heating which
might not have come from an internal arc-over but
from somthing else.
I suspect one of the cables that connects to one of
the primary connection terminals in the lid of the container.
I have to connect the wires and then put the lid on top,
therefore the wires are pretty long and might have touched
the core of one of the outer transformers. As the cable is only
cloth insulated, there would just be a small gap of cloth and oil
which I doubt would stand the 10KV, maybe not arcing but
some current flow or corona like leakage.

OK, so much for now, thanks a lot for you answer and kind offer.

best regards

Christoph


----- Original Message -----
From: "Tesla list" <tesla@xxxxxxxxxx>
To: <tesla@xxxxxxxxxx>
Sent: Sunday, July 03, 2005 8:06 PM
Subject: Re: MOT stack rebuild


> Original poster: "Paul B. Brodie" <pbbrodie@xxxxxxxxxxxxx>
>
> Christopher,
> Where are you? I'm afraid of the answer. I have a bunch of MOT's and would
> be more than happy to send you one. If you are overseas this might not be
> viable.
> Paul
> Think Positive
>
> ----- Original Message -----
> From: "Tesla list" <<mailto:tesla@xxxxxxxxxx>tesla@xxxxxxxxxx>
> To: <<mailto:tesla@xxxxxxxxxx>tesla@xxxxxxxxxx>
> Sent: Friday, July 01, 2005 2:37 PM
> Subject: MOT stack rebuild
>
>  > Original poster: "Christoph Bohr"
> <<mailto:cb@xxxxxxxxxxxxxxx>cb@xxxxxxxxxxxxxxx>
>  >
>  > Hello Folks.
>  >
>  > I am currently in the process of rebuilding my 6MOT
>  > stack as I wired the primary side with a too thin gauge
>  > wire and am expecting significant losses there.
>  > So I drained the oil, but now I have two more questions:
>  >
>  > Should I remove the shunts? I do not need more current,
>  > but I fear  with the shunts in place I might experience
>  > other negative effects, as lower output voltage or
>  > increased no load current draw.
>  > With no load it pulls around 8 amps which sounds pretty
>  > much to me, or am I missing something?
>  >
>  > The other thing is, I fear one MOT might have experienced
>  > a breakdown of the insulation. But when I do a low voltage
>  > test, everything works fine. ( However, I have no way to
>  > measure the secondary voltage with 230V in, only with 12Vin )
>  > I believe it might be possible, that the insulation broke down,
>  > but after switching off, the oil caused some kind of "selfhealing"
>  > action.... probably just wishfull thinking.
>  > The physical arrangment makes it impossible to access the
>  > possibly affected mot, so I have to disassemble the stack first.
>  > Is there a way to test the single xformer alone outside the stack
>  > for this kind of failure mode?
>  > Unfortunately I do not have access to more MOT's, otherwise
>  > I would simply change the one transformer...
>  >
>  > Thanks a lot in advance
>  >
>  > regards
>  >
>  > Christoph Bohr
>  >
>  >
>
>
>