John,
It's according to what type of rectifier circuit you'd use with the capacitor.
For a full wave bridge and capacitor input, the secondary current is from 1.6
to 1.8 times the DC current. That variance I don't know for sure where both
came from as some formulas I've seen use either. It has a lot to do with the
size of capacitor of course. Hammond has a downloadable pdf with these formulas
in it, and I'm pretty sure they use 1.6. Ohter transformer manufacturers though
I've seen use 1.8.
The one you found, didn't the primary have it where you could change the
voltage? Most always had this because there are some places using 220/240 VAC.
Best,
Will
*********** REPLY SEPARATOR ***********
On 3/21/06 at 5:39 PM John T. M. Lyles wrote:
>Before I start searching for 3 KVA pole pigs I will ask here. I have
>a UTC LS-184, a beautiful transformer from the 1950s, weighs 102 lbs.
>It is 7 kV RMS CT. With a choke input, it would do a 3 kV DC 500 mA
>supply all day long, according to UTC. I need ~ 4 kV at 0.6 - 0.8
>Amps. If I ran it into a capacitor only, and it charged up to near
>peak, it should do the voltage fine. However, I am not certain how
>much current derating it would need for running into a Capacitive
>load.
>
>Does anyone have a single phase plate transformer, which has 220/240
>primary and good for ~4 kV DC @ 0.6-0.8 Amps? I would prefer to us a
>full wave bridge but two diodes and a center tapped pig would work
>too. I just found a 4.1 kV @ 2 Amp today at a junk yard in town, but
>it has 480 VAC primary, and is LARGE. I have several pieces for 3 kV
>DC supplies, but nothing for a higher voltage tube. Numerous
>broadcast transmitters and RF industrial generators used such power
>in the good old days.
>
>There were some very nice 3 kVA 4160VAC/220 dry distribution
>transformers made by Westinghouse years back, before ABB bought them,
>and they outsourced to China. Into a choke, they would be fine. I am
>not planning on using this for SSB.
>
>Thank you.
>73
>John
>K5PRO
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