Re: MOT power supply

["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>

Hi Johathon
Yes you can ground all the cores
I believe it is safer to do this to put an earth barrier between the HV sec
and mains. Granted the mains will sink any excess HV to ground but I like to
remove any chance of ths event. (see multiple earth neutral systems)

It does not get over the problem that the whole secondary of the outer MOT's
is elevated WRT to earth.
By careful selection of MOT's and the use of oil. (which is not messey if
correctly managed) the voltage does not pose a problem. Myself and many
experimenters have made 6 MOT systems without a hint of problems. As these
paks are phased around earth only half the O/P volt stress appears on the
last MOT

Also the outer sections of the last MOT secondary see the greatest stress
and fortunately this is the most exposed part so the oil has best access to
do it's job.

Best
Ted L in NZ
Where upgrade from 6 to 8 MOT's is on the dwg board


 > >It is not the voltage across the windings that is the problem.
 > >It is the secondary to primary voltage that is.
 > >
 > >When you string these transformers together, the last transformer in the
 > >string will have its secondary elevated to a potential that equals the
 > >sum of all the transformers output voltage in that string. From the
 > >ground point and out.
 > >
 > >Since the primary coils all are at relative ground potential, the sum of
 > >primary and secondary insulation to the core, on the last transformer,
 > >is stressed beyond the design mark.
 >
 >
 > Would it be practical to disconnect all secondary to core leads, and
ground
 > the cores?
 >
 > Jonathon
 >
 >
 >