[Amps] SCR to adjust 240v to 200v

[Steve Wright]

If you can drop the filament voltage by winding an opposing turn 
somewhere, or maybe a large resistor - the rest of it can probably be 
ignored.

Test the 200V transformer running at 230V, by removing the tubes or 
disconnecting the filaments, then power-on and monitor the transformer 
core temperature.  Core temp shouldn't be "warming fast and getting 
hotter and hotter".  If you feel you can put a fan on the transformer 
and it will remain under 50-70 celcius, then I'd be tempted to run it 
like that.

Steve


On 16/08/16 01:45, Jim Durham <jimdur at gmail.com> wrote:
> Talked to Henry. They asked me the plate transformer number, which they
> looked up and said "Oh, that's the 200v European transformer". So, I put a
> hefty variac on the 240v AC incoming and all is fine, except I'd like to
> ditch the variac and was wondering about if anyone on here had any wise
> words about using an SCR instead to back the AC voltage off.
>
> My experience with big SCRs (TV studio lighting) was that they tend to
> put out a lot of RF hash.  I also wonder about how the choke and filter cap
> in the power supply would like non-sinusoidal AC waveform?
>
> Anyone have any experience with this?
>
> Thanks and 73,
>
> Jim, W2XO
>
>