----- Original Message -----
From: "Carl" <km1h@jeremy.mv.com>
To: "Mike Lucas" <w5chr@bellsouth.net>; <amps@contesting.com>
Sent: Monday, March 16, 2009 7:20 PM
Subject: Re: [Amps] P/S upgrade
> Whats the value of the choke?? Old handbooks have all the info on thise
> selections that you will ever need.
>
> Yes a variac is just an added stage of regulation to contend with unless
> it is a monster.
Carl:
What qualifies as a monster?
On my largest power supply here, which is an early, untapped, Peter Dahl
unit that runs 5000 volts at 2 amps, I use a 30 amp variac.
Under a 1.5 amp load, with the output voltage set at 4200 volts, no load, I
see about 15% sag under key-down conditions.
Part of that sag is very likely the variac, but when I had the shack wired
for 240 years ago I specified number 8 wire. I got number 10. It's over a
hundred foot run, so I think I'm losing something there, as well.
73, Barrie, W7ALW
>
> Carl
> KM1H
>
>
>
> ----- Original Message -----
> From: "Mike Lucas" <w5chr@bellsouth.net>
> To: <amps@contesting.com>
> Sent: Monday, March 16, 2009 7:59 PM
> Subject: [Amps] P/S upgrade
>
>
>>I have an OLD homebrew supply for a single 4-1000,
>> that needs some re-work before using it with an amp.Transformer weighs
>> 103lbs, with a 28 lb choke input in the neg lead. Rectifiers are 3 amp
>> individual diodes in a bridge configuration.
>> Questions are: is 16Mfd enough at 5 Kv and 540mils, if not, how much?
>> And
>> why will a variac cause poor regulation?
>>
>> 73, Mike W5CHR
>> Memphis
>>
>>
>> _______________________________________________
>> Amps mailing list
>> Amps@contesting.com
>> http://lists.contesting.com/mailman/listinfo/amps
>
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