>
>Just a aquired a surplus 4cx5000 rf deck and power supply which is odd
>ball volts and frequency, looks a like a aircraft amp.
>I need to build a 7500 volts 2 amp pwr supply. What is the most suitable
>approach?
? For mine, I used a 3000Vrms Peter W. Dahl 68-pounder, which I potted
with laminating resin as per the info on my Web site. I used a FWD. No
load was 9100v. Transmitting on SSB, the supply delivered c. 7800v.
>. Where do you get 30000 volt 2 amp diodes,
? For a FWD, the actual piv is a bit under 10kV per leg. 15kV total per
leg would provide a 50% safety factor. Mount 2 x 15 1N5408s on a
perfboard, sans-"equalizers", sitting in the air stream and you have it.
. 1N5408s go for about 20 cents each these days
> and is a C filter suitable with this size power supply?
? Sure, for ssb and cw (by switching to a FWB -- ckt on my Web site).
However for RTTY and FM, a resonant-choke filter is way better. The
thing to keep in mind with C filter supplies is that the peak mains
current is about 10x that for a similar resonant choke supply. Thus, you
gotta use huge wire to the mains breaker box with a C filter. For a Dahl
68 pounder, #4 copper is adequate for up to c. a 30m run. ( notes /
Dahl's 68-pounder has a bar-stock primary winding with c. 0.078 ohms of R
/ To covert Dahl's "vA" rating to ssb pep watts out, multiply by c. 3,
).
> Also what minimum C should be used
? I would use (2 x 11) 470uf, 450wv, 105 deg C Panasonic filter caps
mtd. on an acrylic or g10 sheet with silicone rubber adhesive. Panasonic
100k-ohm, 3w resistors work well as equalizers. // If you could swap
for 4cx10,000D, the difference is a more efficient anode cooler. This
would allow you to use a 1700 rpm blower instead of a much more noisy
3400 rpm blower.
>.....
- later, Bill
Rich...
R. L. Measures, 805-386-3734, AG6K, www.vcnet.com/measures
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