[Amps] An inexpensive choke for a resonant filter

[Radio WC6W]

   Here are some real numbers for simulation:

      A 3KW Varian plate transformer (85 lbs)
            240V Primary --  2.2 ohms DCR,  40 mHy
inductance
            3200V 1A Secondary -- 22 ohms DCR, 9H
inductance

      A Westinghouse 1A, 10KV choke (50 lbs)
            8H  & 30 ohms DCR

   Doing "research" for a plate supply using microwave
oven parts, I "recycled" a dozen microwaves, garnered
from the "curb exchange", appliance "rated" from 600
watts to 1 KW.

   The transformers were all wound with #14 on the
primary and #26 on the secondary.  The secondaries are
all grounded at one end, though most can be easily
lifted -- Negative lead filtering is a good option in
this instance.

   The secondary inductances measured between 9 & 22 H
with the shunts in place.  The secondary resistances
measured between 70 & 110 ohms.  They weigh from 8 to
10 lbs each.

   The capacitors run between .72uF and 1uF with the
median around .9 uF.

   Perhaps, two or three "matched" microwave
transformer secondaries connected in parallel with 3
or 4 of their caps connected in series, then across
the transformers would be a good substitute for a real
8Hy 1A choke. 

     And a couple more data points for the resonant
choke filtering thread:

     The Collins 30S-1 used 8H & .15 uF in the plate
supply and 3.5H and .5 uF in the screen supply.

     I once used the 8H Westinghouse part noted above
& .2uF at 5KV in a resonant configuration in my 4CX1000A
power supply.  See:
http://wc6w.50webs.com/wc6wamps/index.html?fr131.html

73 & Good afternoon,
   Marv WC6W

http://wc6w.50webs.com/







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