Re: filament trans.

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

Original poster: "Gregory Hunter by way of Terry Fritz <twftesla-at-qwest-dot-net>" <ghunter31014-at-yahoo-dot-com>

Recently my sister-in-law gave me an 833A power triode
she was using as a bookend.  She had no idea what it
was, and I bothered her about so much she finally just
gave it to me.  Anyway, the big tube called for a 10V,
10A filament supply.  In a big fat hurry, I chopped
the secondary off of a small MOT, taking care not to
damage the primary.  I left the shunts in, and rewound
it with a few turns of stranded 12AWG THHN wire.  It
puts out 10VAC exactly, and lights the 833A heater
perfectly.  It was cheap too (free)!  There's plenty
of room left in the core window should I care to add a
6.3V or 12V winding.

My $.02 worth,

Greg
http://hot-streamer-dot-com/greg

PS:  I've added some captured video pics of my
recently rebuilt 4" x 24" 1080VA NST coil:
http://hot-streamer-dot-com/greg/sparkz.jpg

--- Tesla list <tesla-at-pupman-dot-com> wrote:
> Original poster: "Metlicka Marc by way of Terry
> Fritz <twftesla-at-qwest-dot-net>" <mystuffs-at-orwell-dot-net>
> 
> hi all,
> for those looking for a filament transformer for
> there tubes in a vttc,
> i have made a nice one out of a 1000w 208\277v HID
> ballast transformer.
> i left the 208\277v primary in place a wound twin
> 12g windings around a
> home made bobbin for 12 turns each, this worked out
> to the 5v i need for
> my VT-127A'S. the trans. now gives me 5v from the
> 277v winding, 7.5v
> from the 208v winding, 10v from the two combined
> from the 277v winding
> and 15v from the two and the 208v windings.
> i left all the shunts in place because with the
> normal 330v-at-800ma
> output, the new windings should give 52 amp on the
> single 5v winding.
> much more then the wire will stand, i now wish i
> would have used 10 or 8
> g wire because i have the room. i have three more
> exact same ballast's
> so the next will use heavier wire.
> just thought i'd mention this cheap and easy
> filament transformer
> because most could get the ballast's from there
> local electrical
> contractors that deal with  high intensity discharge
> lamps.
> take care,
> marc m.
> 
> 
> 


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