Checkout Rich Measures web site on why you shouldn't use a variac in the
primary and also why older transformers designed for use with a choke
shouldn't be used with a capacitor filter.
If you need a custom made transformer or choke then I've already posted
the web site of one company I've used in the UK, and whom I'm pretty
sure will manufacture a choke to your spec - but when designing a power
supply with choke smoothing unless you either have a constant load
(FM/RTTY) or use a swinging choke then you may run into problems.
There a useful program on Duncan Amps website for designing power
supplies.
I also have a transformer which I want to dispose of...
110 or 240 volts input, centre tap bi phase output at 2.5, 3, or 3.5KV
per leg @ 248Ma.
Possible DC output voltages 3.5KV, 4.3KV or 5KV at 248 Milliamperes
after capacitor smoothing.
There'll be some leeway on these voltages if you move the primary taps
around. Also the rating is 100% duty cycle, if used in SSB for example
then the rating can be upped considerably.
Paul
In message <NEBBJCEAJLONNBGCHLCHEEJMCCAA.philhss@breathemail.net>, Phil
<philhss@breathemail.net> writes
>
>
>Gentlemen,
>
>I posted to this reflector late last year with a query regarding using the
>DJ5RE design with a GS35b on 144MHz - with great success! I am happy to
>report that the project is coming along just fine, with the only problem to
>date being the acquisition of suitable finger-stock to make a 'socket' for
>the tube. I know I can do this by other means, but I'd like to take this
>route...
>
>However, this is not the point of my posting.
>
>I'd like to feed the anode of the GS35b with 4 to 4.5Kv DC. Many others have
>had great success with this level of voltage on the anode so I've chosen
>this as my goal.
>
>I've managed to get my hands on an HV Transformer which features a
>3950-0-3950 secondary, and a 10-0-180-200-220-240 primary. The only ID on
>the unit is "M.E.P. M1921 SR/T 2468".
>
>The question is: How do I tame the beast so as to provide the required level
>of DC from a 240v AC supply?
>
>I immediately thought of placing a 240/110 transformer in the primary to
>feed the 'main' transformer with 110v onto the 240 primary tapping. This
>would be fine, except that sourcing such a transformer in the UK has proven
>difficult.
>
>So, a friend has suggested using a full-wave rectification setup with a
>filter choke - but by my calculation this requires a choke of some 5H or
>more! How do I build such a choke, or where can I purchase one?
>
>Maybe you know of a better way? Any help/suggestions would be greatly
>appreciated.....
>
>Happy New Year, Chaps!
>
>Phil Smeaton
>G0HSS
>
>
>--
>FAQ on WWW: http://www.contesting.com/FAQ/amps
>Submissions: amps@contesting.com
>Administrative requests: amps-REQUEST@contesting.com
>Problems: owner-amps@contesting.com
>
>
--
To try and not succeed is better than not to try at all (Anon)
--
FAQ on WWW: http://www.contesting.com/FAQ/amps
Submissions: amps@contesting.com
Administrative requests: amps-REQUEST@contesting.com
Problems: owner-amps@contesting.com
|