[HomeBrew] Fw: My model train transfomer variac idea: clear-up comments

[DavidE Benedict]

(Some (most?) model train control units supply dc so the ac voltage output
would have to be tapped
ahead of the rectifier(s).)

My old Marx & Lionel were AC
David
W7DBH


meils at get2net.dk,Internet writes:
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>There seemed to be a misunderstanding -- the variable low voltage (0-
>about 30 Vac) is fed to 
>directly to a separate  filament (or old fashioned door-bell)
>transformer's low voltage/filament secondary winding and will thus
>produce from 0 to >120 Vac (0 to >240 ) at the primary winding, depending
>on the setting of the control arm on the train transformer and the rated
>voltage of the reverse connected transformer's low voltage winding(s). 
>
>This not  is a conventional series- connected  few-volt
>bucking/subtractive or additive configuration.
>
>My point is that variacs can be expensive (at least on this side of the
>pond) and this is 
>a  cost-free way of controlling low wattage gear if you happen to have
>one of these model train 
>units and a filament transformer at hand.
>
>(Some (most?) model train control units supply dc so the ac voltage
>output would have to be tapped
>ahead of the rectifier(s).)
>
>73, 
>Henry OZ1UF / N2NR
>
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