I have a HB B+ supply that uses a variac on only one side of the 240 vac. It
is a 115 volt unit rated at 18 amps. Works great. With the variac in line I
only drop 100 volts more than w/o. The dc filter network is a copy of the
Henry 2K, 3K, et. and is a resonant choke with 32uF of cap after it. I tried
a 240 vac 10 amp like the one used in the ARRL Handbook but it was dropping
an additional 250 volts. Since it has step-start and I do not need to go
below 2500vdc I decided to go with the 18amp unit on just one side of the
primary and it improved regulation quite a bit. I like the freedom the
variac gives me.
Lane
Ku7i
>
> >BUT I am still not convinced that the VARIAC is not a good idea !
> >
> With a resonant choke filter, Variacs are pretty much ok. With a
>capacitor filter, the regulation is not wonderful. .
>
>- Rich..., 805.386.3734, www.vcnet.com/measures.
>end
>
>
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