[Hallicrafters] Bucking Transformer

[Carl]

The bucking transformer is such a simple and elegant solution that can be 
used to select whatever voltage you want and it wont be prone to possibly 
causing equipment damage as some other methods suggested. There are even 
commercial amps with buck/boost primary windings so voltages can be 
controlled as desired.

Carl
KM1H


----- Original Message ----- 
From: "David Thompson" <thompson at mindspring.com>
To: <hallicrafters at mailman.qth.net>
Sent: Wednesday, June 20, 2012 5:43 PM
Subject: Re: [Hallicrafters] Bucking Transformer


> Years ago I had a big auto transformer that we mounted above the power
> supply
> for a 4-400 amplifier.  Almost everything in those days was on 110V AC and
> we had a big 50A circuit.
>
> The auto transformer allowed me to step up the voltage to about 145V and
> down to less than 40 volts.  One of my elmers W5DYJ said this was better
> than a variac.
> I think it had at least 10 or 12 steps.  I recall the transformer weighted
> about 50 pounds and was made by transformer Corporation of America in New
> York.  W5DYJ had Masters and PHD's from Columbia so New York made sense. 
> I
> found Frank Lester W4AMJ Ex W2AMJ worked for them in the early 1950's.
>
> The main times the auto transformer was used was to slowly test out a new
> 4-400 and to reduce power to less than 150 watts input using a 4-125 so I
> could operate the ARRL Phone SS (AM phone).  I found one of the 4-125's 
> used
> back then in my junk box.  I always got a signed statement from a local 
> club
> official that I was running 150 watts input or less.
>
> So guess I ran a bucking transformer years ago.
>
>
> 73 Dave K4JRB
>
>
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