[Amps] Small transformer evaluation

Vic K2VCO k2vco.vic at gmail.com
Sat Sep 1 16:37:10 EDT 2012


Some of you will remember that I was wondering about utilizing a small Philco power 
transformer (model 45-7011-7) for a screen supply. It puts out 380-0-380 vac plus 5 and 6 
v for filaments. I have hooked it up jn a full-wave ct circuit feeding a choke-input 
filter and 20 uf capacitor. It is feeding a 4300 ohm 50w resistor for a load.

I measure an AC voltage of 378v on either half of the secondary and 315v DC across the 
load (83% of the AC). Current is about 73 ma. It has been sitting for about 20 minutes and 
I can detect a very slight rise in temperature of the transformer. I am going to let it 
sit for at least an hour.

I think that I am proving that I will be able to draw this much current, but the voltage 
is too low. Next I am going to try it as capacitor-input and see what happens.

-- 
Vic, K2VCO
Fresno CA
http://www.qsl.net/k2vco/



More information about the Amps mailing list