[Amps] 3 phase power supply?

[GeorgeWallner]

I used a rotary single-to-3-phase converter for 12 years. 
(It is not really a 3 phase converter, as the original 
phase is re-used - and only to phases are added) to power 
a 2 x GU84B (4X1500B) amplifier. Yes, the other voltages 
were all over the place but the filament voltage was 
pretty steady at 31 volts AC.  (The spec for the Russian 
tubes calls for 28 V AC). After 12 years (when I got a 
real 3 phase supply), I could not detect any deterioration 
in the tubes. So I would not worry about it too much, as 
long as the tubes are not under-heated.  Overheating is 
OK, probably up to about 10% over the filament voltage 
specs.

GW


On Sun, 2 Apr 2017 21:56:06 -0400
  Ron Youvan <ka4inm at gmail.com> wrote:
>   Steve NR4M Bookout wrote:
> 
> /* snip */
>> But, another thing to consider.  I was looking a the 
>>schematic and saw
>> where some of the smaller transformers were fed from one 
>>phase, while
>> the HV was fed by two phases.  Again, from what I read, 
>>the voltages of
>> the 3 phases created from a rotary converter, vary 
>>according to the
>> load.  My concern is with the filament supply.  If it's 
>>off one leg, and
>> I was to vary the 240 input to get exactly what I need 
>>for the filament,
>> what happens when I start drawing power and that leg now 
>>changes by 10
>> %, or so.
> 
>> Other choice is to just build a new 240 volt single 
>>phase supply for all
>> the required voltages.  It's just that the 3 phase 
>>supply is part of a
>> really clean 'system' and it would be nice to keep it 
>>original, if
>> possible.  This seems like it would be the most stable 
>>and reliable.
> 
>> Thoughts?
> 
>   It looks like it is not actually a three phase device 
>and it most probably can be run on `210 Volta (or so) 
>possibly with the aid of a
> buck boost transformer or two.
> I would look into the current consumption of the smaller 
>transformers to see if they can be paired up to run in 
>series.
> I would also look for primary taps on the smaller 
>transformers, if so
> perhaps pairs could be run on 240 Volts.  My thoughts.
> -- 
>   Ron  KA4INM - Youvan's corollary:
>                 Every action results in unwanted side 
>effects.
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