[GreenKeys] Another idea for a loop supply transformer

[Gerry Block (sbcglobal)]

Ken I wouldn't recommend this as the insulation characteristics between two primary windings is not sufficient for safety reasons.  I would use the other recommended method - back to back filament transformers.  Much safer.

Gerry
-------------- Original message from Ken Schwieker <ksweek at mindspring.com>: -------------- 


> When building a ST-6 many years ago I used a transformer that had a 
> dual primary for 115 or 230 volt operation. The secondaries were used 
> for the low voltage and the second primary as a loop supply winding. 
> The total loads of the low voltage secondary and the new HV secondary 
> were checked to be sure they totaled less than half of the total 
> wattage that the transformer was rated for to prevent overloading of 
> the primary. Any sufficiently rated transformer can be used the same 
> way for a loop supply. 
> 
> The transformer used in my ST-6 is a Stancor P-6377. It has two 12 
> volt 2 amp secondary windings as well as the two 115 volt primary 
> ones. It made for a fairly compact ST-6. A link to a picture is 
> below. The outside transformer shell was lifted off of another 
> transformer for protection. 
> 
> http://www.mindspring.com/~ksweek/images/ST-6.jpg 
> 
> This or any other suitable transformer could have been used alone 
> with the two secondaries wired to buck either the input or the output 
> to give a somewhat lower output voltage if desired. 
> 
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