Re: MOT Powered Coil

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

Original poster: "Luc by way of Terry Fritz <twftesla-at-qwest-dot-net>" <ludev-at-videotron.ca>

Hi Steve,

I used the method 3 in my present PS but I leave the MOT B core
floating, may be I'll try the resistor divider. The 2 Mot are in
oil and screw to piece of wood that I boiled in oil before I used
it the wood permit the core B to electrically float, I used this
method because I want a ground reference in my PS:

http://pages.infinit-dot-net/luc2/ps_mot_3.gif

Cheers,

Luc Benard

Tesla list wrote:
> 
> Original poster: "S & J Young by way of Terry Fritz <twftesla-at-qwest-dot-net>"
<youngs-at-konnections-dot-net>
> 
> Mark, see comments below:
> ----- Original Message -----
> From: "Tesla list" <tesla-at-pupman-dot-com>
> To: <tesla-at-pupman-dot-com>
> Sent: Saturday, January 12, 2002 5:12 PM
> Subject: Re: MOT Powered Coil
> 
> > Original poster: "by way of Terry Fritz <twftesla-at-qwest-dot-net>"
> <A123X-at-aol-dot-com>
> >
> > Will an MMC rated for 12Kvdc be enough for the twin MOT supply with an
> output
> > of 8Kvac or technically a round 11KVDC?
> ANSWER:  I believe Terry would say yes.  If it was me, I would feel more
> comfortable with at least a 15 KVDC MMC.
> >Also, if I used 4 MOT's in series how
> > much will it matter if some are kinda a bit smaller and the voltage output
> of
> > them varies?
> ANSWER:  It will be OK.  The smaller one(s) may get a bit warmer under load
> than the others, but that's ok.
> 
> It would seem to me that the large MOT's would put out more of the
> > power [ANSWER - usually true] and even if this isn't the case wouldn't an
> 1800v MOT put out more
> > current than the 2000v or 2100v ones causing things to get messed up? or
> do
> > things just even out?
>  > Mark
> 
> ANSWER:  The 2000 or 2100 volt MOTs may put out more current if, for
> example, the 1800 volt model was for a 500 watt oven and the 2000+ ones were
> from large or commercial ovens.  Whether more or less, it won't "mess up"
> things.  Most MOTs can put out more current than you need anyway for small
> and medium sized coils.
> 
> Ideally, you would like 4 matched MOTs, but that is tough to find.  So just
> use what you have.
> 
> Now I have a question about putting two MOTs in series.  Three ways of doing
> it are 1) connect the secondary outside winding of MOT A to the core of MOT
> B.  This puts voltage stress between the MOT B primary and the core.  2)
> connect the secondary outside winding of MOT A to the inside winding
> (disconnected from the core) of MOT B and ground the core.  This puts
> voltage stress between the inside of of the MOT B secondary to the core.  3)
> (I have never heard of this being done) connect the outside winding of MOT A
> to the disconnected inside winding of MOT B (same as 2), and use a high
> value resistor divider across MOT A to make the core of MOT B be about half
> the voltage of MOT A.  This would share the voltage stress between the MOT B
> primary and inside winding of the secondary.
> 
> Which method is most likely to avoid insulation breakdown in MOT B?  Anyone
> know the typical breakdown voltage of a MOT primary to the core as compared
> to a disconnected MOT secondary to the core?
> --Steve