[Amps] SCR to adjust 240v to 200v

[Peter Voelpel]

Racal regulated all power supplies in their TA1800 amp with SCRs except
anode voltage.
They used transformers with 205V primary for the heater, the bias and the
screen of the 4CX10000. 
The screen voltage was also used to supply the three 4CX350A drivers and
predriver.

No interference at all!

73
Peter

-----Original Message-----
From: Amps [mailto:amps-bounces at contesting.com] On Behalf Of Manfred
Mornhinweg

conduction doesn't cause big trouble.

I agree with those who warn that interference could become a big 
problem. Unlike MOSFETs or bipolar transistors, the switching speed of 
SCRs cannot be controlled. Once triggered, they switch on very fast, and 
that creates a very considerable amount of RF energy. You will have to 
control that noise purely with filters and possibly some shielding, and 
it may not be easy.

Considering the tremendous advantage in terms of size and weight, and 
even in cost, I think that you should try it. But if you cannot get the 
noise under control, in the end you might have to resort to the external 
bucking transformer anyway!