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Re: MOT - PSU
Hi Herwig,
> Original Poster: "Herwig Roscher" <herwig.roscher@gmx.de>
> Hi fellow MOT coilers,
>
> For my new VTTC unfortunately I havn't found a
> suitable plate xformer yet. Therefore I'm
> thinking of using a couple of MOTs instead. My
> YU-204 tube is intended for pulse use and will
> require more than 2.5 kVdc I can get out of the
> 1.8 kVrms MOTs used in this part of the world.
Snip.
Try looking for bigger microwave ovens with Gardner (U.K.)
MOTs. These put out 2.3kV at 650mA rated (measured,
too). Antiparallel both on the 230V side and series the two
on the secondary side. Center tap the connection coming
from MOT #1 and going into MOT#2 and ground it. That
way, you will get 4.6kV@ 650mA (making ~3kVA) without
overvolting the secondaries of the MOTs. These Gardner
MOTs are up to the job and their insulation is better than
most of the MOTs, I have seen. If you want to go to the
trouble to build a set of two (meaning 4 MOTS) isolation
xformers you could use 4 of these Gardner units to get
9.2kVAC at 650mA (~6kVA). That should give your VTTC
a smokinŽ (pun intended) hot output. Actually, I have run 4
of these in series w/o isolation xformers and they held up
beautifully in air. There was no corona to be seen in the
dark. A 5th one in series (NOT of the Gardner type) didnŽt
last long, before it arced to the core (not surprising).
However, even then, the Gardner MOTs did NOT arc over
or die.
The only problem is FINDING these brutes, but maybe
youŽll have more luck than I did ;o))
Coiler greets from (and back to) Germany,
Reinhard