[Collins] Bucking Voltage

[Heinz und Hannelore Breuer]

Hi Dave,

this topic "Bucking transformer" has been discussed on various
boatanchor lists several times. I just don't remember if it showed up
here before.

A 5V transformer is too small. Better take a 10V or even a 12,6 V
filament transformer. Most line voltages are running at 125V or even
higher. Getting it down by 10V or even more would be for the benefit of
the transformers. The A-line might have been made with a 110V primary
back then.

Choose a transformer with a secondary current rating high enough to run
the primary current of the Collins unit you want to use. Connect the
secondary of this transformer in serial with the primary of the Collins
unit. Connect the primary to the line voltage. Just make sure it "bucks"
the voltage and does not "step it up". If it steps up just change the
wires.I made an external box containing the bucking transformer, it has
a power cord which goes to the power outlet in the wall and also an
outlet where I plug in my unit which I want to run on a reduced line voltage.

73
Heinz DH2FA, KM5VT




David Knepper wrote:
> 
> Someone mentioned that they use the unused 5 volt secondary winding to buck
> the primary voltage in an HT-37.  I wonder if the same could be done with
> the power transformer in the Collins 516F-2.
> 
> I wonder why this trick circuitry has not been discussed before to reduce
> the A.C. voltage on the primary, thus, giving some relief to the transformer
> from the over 120 volt line voltage in many areas.
> 
> Thank you.
> 
> Dave, W3ST
> Secretary to the Collins Radio Association
> Publisher of the Collins Journal
> www.collinsra.com