Re: MOT mod.

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

Original poster: Terry Fritz <teslalist-at-twfpowerelectronics-dot-com>

Hi,

Trial and error ;-))

Using a volt meter and some heavy wire that can take the final 6.5 amps, 
just wind a few turns till you get to 5 volts.  It will not take many turns 
at all.  Then put the tube load on it and wind another few turns as needed 
to get your 5 volts.  the current will work out automatically once the 5 
volts is obtained.

Cheers,

         Terry

At 08:17 PM 1/16/2004, you wrote:

>In an attempt to throw together a tube style TC, I have
>determined (mainly by the state of my finances) that I
>will need to modify an old MOT to supply the 5 volts
>that the tubes use.  After about an hour of work, and a
>massive quantity of frustration, I was able to fully
>remove the secondary winding, and the original filament
>winding, leaving the MOT's primary and shunts unscathed.  Now I need to know
>how many turns of wire to insert into
>the MOT core to get the voltage and sufficient amperage to
>run the tubes.
>
>The tubes are a pair of 4-125A (Sylvania) radial beam
>power tetrodes, wired in triode mode.  The specs say the
>filaments require 5 volts -at- 6.5 amps.
>
>I'm sure with the huge collective of experience there is
>in this list, someone must have a pretty good idea of
>what I need to do to get the job done.
>
>Help!
>---
>C.L. Mayeux
>Owner, MSB Data Systems
>http://www.msbdatasystems-dot-com