With this level of Ep I would consider 811As. I believe 813s work much
better closer towards 3kvdc Ep. My Heathkit Warrior HA-10 project I am
working on runs about 1600vdc on the plate and I am seeing about 650 to
750 watts out but the current capacity of the PS in the HA-10 is fairly
stout using a choke input filter network, etc.
LT Lane Zeitler
Ku7i
Currently onboard USS Peleliu LHA-5
-----Original Message-----
From: amps-bounces@contesting.com [mailto:amps-bounces@contesting.com]
On Behalf Of Vic K2VCO
Sent: Friday, March 19, 2010 11:33 AM
To: Amps reflector
Subject: [Amps] Utilization of old TV transformer
I have an old TV power transformer that I am thinking about using as a
plate transformer
for a medium-power amplifier (2 x 813).
It weighs between 15 and 20 pounds and the stack is 3.25" x 4.5" x 4".
It has a hv winding for 680v at 290 ma and four filament windings which
I wouldn't use.
The total VA output of all the windings is 313. But remember this rating
assumes
continuous duty.
The amplifier will be used on CW, so the duty cycle will be about 50%. I
would need to use
either a doubler or tripler circuit to get a reasonable voltage for the
813's.
My guess is that a doubler would give me about 1900v which would
probably drop to about
1700 under load. If the 813's were loaded to 400 ma that would be 680
watts input.
With a tripler I could get 2800v which would probably drop to 2400. At
360 ma plate
current that gives me 864 watts input.
My feeling is that the transformer would be OK with the first
configuration, but the
second would be too much for it.
Do you agree? Or should I forget about using this transformer and look
for a better fit?
The fact that it's free is a big incentive.
--
Vic, K2VCO
Fresno CA
http://www.qsl.net/k2vco/
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