On Mon, 19 Oct 1998 13:53:22 -0700 "Will K6NDV" <k6ndv@contesting.com>
writes:
>
>Here some interesting information about transformers.
>I asked Bob's opinion about transformers and this is what he send me.
>Will, K6NDV
All good advice Will. Just permit me to add a short comment.
Usually, transformers designed for full wave service AND tube rectifiers
make poor choices for SS service. The secondary resistance is typically
well over 250 Ohms for an example a 4-1000A E & I rating and when going
to SS rectifiers the regulation will be horrible. Yes there are
exceptions but I have been on the telephone or on the air with too many
hams who want to know why they go from 5000VDC key up to 3000 key down. A
good xfmr, even capacitor input, should hold regulation to a max of
roughly 12 percent. Except for AM service or maybe a monster amp, I see
no reason for a choke.
If I could make any suggestion it would be to stay away from non descript
flea market bargains, buy from someone that can describe the service the
xfmr came from and/or save your money and buy a new one. There are
several small xfmr manufacturers that can wind to your specs at
considerable savings over Dahl.
73 Carl KM1H
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