Re: MOT power suply, transformers in series...

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

Original poster: "tesla by way of Terry Fritz <twftesla-at-qwest-dot-net>" <tesla-at-paradise-dot-net.nz>

My observations
1) Similar core size matching is good, go for biggest volts you can find.
2) Outer MOT's select for best sec winding to core clearance and insulation.
Anchor lifted secondary winding an tag strip and fill area with hot glue. It
is surprising how much variation there is in core to secondary clearance.
3) Outer MOT's (the ones with secondary at elevated potential) need to be in
oil for reliability and helps heat removal. No problems so far with 4 and
limited running with 6. Cleanliness is next to godlyness here. Wash MOTS in
alchohol before putting in oil and dry under lamp to remove all traces of
alchohol and residual water vapours in MOT
4) Modest PFC is useful but not essential
5) I've placed 3 per side OK but tend to experiement with just 4 total .
Will use 6 total later when coil is perfected
6) Some modest inductive ballasting assists in managing mains current. ( I
use 11mH on each MOT side)
7) Currently trying running each 1/2 of the two groups of MOTs from separate
mains outlets (same phase different breaker) to assist is spreading the load
on the mains wiring. Can easilly parallel if required using "Tapon" mains
plugs. This can effectively double the available mains I/P. In NZ mains
outlets are 10A/230V max and I need closer to 30A total
8) 6" PVC downpipe and fittings make neat inexpensive oil containers for the
MOT's they just fit in (sometimes remove the old mtg feet)
9) I think it's possible to run one 1/2 of the MOT's from uncontroilled
mains and the other from a variac. This gives 1/2 power at first then ramp
up on the variac to full power. This helps for those who don't have a variac
capable of total mains draw. If only running up on the variac 1/2 short the
unused mains I/P of the other 1/2. Make sure variac is connected and on (but
set to zero) to provide an effective S/C when applying initial uncontrolled
power to other 1/2
10) The whole things lethal CARE !!
11) Run the thing with a fire CO2 extinguisher handy. (never need yet but
feel good idea)

Rgds
Ted L in NZ
----- Original Message -----
From: "Tesla list" <tesla-at-pupman-dot-com>
To: <tesla-at-pupman-dot-com>
Sent: Wednesday, June 12, 2002 12:40 PM
Subject: MOT power suply, transformers in series...


> Original poster: "MeT by way of Terry Fritz <twftesla-at-qwest-dot-net>"
<rasim-at-takas.lt>
>
> hiall!
>
> I'm kind of new to this list, mostly only reading it, but anyway, maybe
> someone could help with information...
>
> Currently I'm constructing my third system, it should be smth around 12kW
DC
> driven, I've allready built capacitor block (0.5uF; 40kV) and now looking
> for suitable power suply.. I'm thinking about MOT's, as they are
inexpensive
> (used of course), but on the internet I can't find good schematics (3
phase,
> 6 transformers, with voltage doubler). Could anyone explain why I just
can't
> connect all six transformers in series (secondaries) to get desired
voltage
> ???
>
>
> thanx in advance..
>
>
> Simonas Jurkonis
>
>
>
>