Power supply sources

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Power supply sources

Postby VE7KHz » Tue Feb 04, 2003 5:03 pm

Hi Guys,

I just "rediscovered" 2 power supplies I forgot I had. They came from our local Telco surplus outlet several years ago. Built for Nortel, they are 48VDC at 25A each. :wink: I just found them today!!

I am going to lift the lid on one to see if I can combine 2 into 1 or split one into 2 supplies for the Class E requirements. 25A is more than enough but one of the supplies needs to float so I may have to reconfigure one of them.

You might get lucky and have one of these Telephone Pioneers stores in your area, and as most telephone systems are 48VDC in North America, you may just find a couple of nice regulated 48VDC supplies cheap in your town.

I'll post pics if anyone is interested. They are nice rack mount units, metered with resettable breakers, dual primaries, heavy line cord etc. :lol:

cheers! :D

Paul
VE7KHz
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Postby blaine » Tue Feb 04, 2003 5:17 pm

the powersupply doesnt need to float, just hooking them in series should do the job.
what does need to float is the small 24vct transformer that supplies the ±12 volts to the TL074(op amp A2) in the audio section. the centertap of that transformer is tied to the output of the modulator.

you should be fine with those two 48 volters 8)
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48VDC supplies

Postby k3xf » Wed Feb 05, 2003 9:24 am

They work well. . . I am using a dual 48V 10A supply for my 40M single FET station. 96V to the class H hi input and 48V to the low provides about 45W carrier and 200W PEP from a Norcal 40M TX. . . no fuss no muss.
That being said the voltage is fixed and I am building a variac/toroid/bridge/BFC PSU for variable voltage and higher current apps.
-ap
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Nortel Supply pics

Postby VE7KHz » Wed Feb 05, 2003 12:19 pm

Here are the links to pics of my Nortel supplies. And guess what! They are switchers!! :lol:

http://www3.telus.net/ve7khz/Dscn5146a.jpg

http://www3.telus.net/ve7khz/Dscn5147a.jpg

http://www3.telus.net/ve7khz/Dscn5148a.jpg

These babies otta make some smoke! :wink:
I used to keep an open mind.......but my brain kept falling out.
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Re: Nortel Supply pics

Postby VK3KRI » Wed Feb 05, 2003 5:47 pm

VE7KHz wrote:Here are the links to pics of my Nortel supplies. And guess what! They are switchers!! :lol:

http://www3.telus.net/ve7khz/Dscn5146a.jpg

http://www3.telus.net/ve7khz/Dscn5147a.jpg

http://www3.telus.net/ve7khz/Dscn5148a.jpg

These babies otta make some smoke! :wink:


Which inevitably leads to the idea.... If you replace the output filter caps with a 8Khz LPF, and apply audio to switch mode controller (fingers crossed about the linearity) do you have a 50 V 25A Pulse duration modulator?

Going one step furthur (into real dangerous territory)! if you were to rectify the mains (as in a switch mode power supply) you could use a PDM straight on this to give about 75V* on carrier and 150V* on peaks. If you used suitably high voltage insulation on input and output ferrite cores the RF amp could be live, but the input and output grounded.

Voila , no 60 lb power transformer (and if your not careful, no ham either...)

Ian VK3KRI

* Double that for those of us with 220/240V mains
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