[GreenKeys] 120vdc at 4-5 amps?

[Bob kb8tq]

Hi

Well …. there *are* some isolation transformers that already have the 6V / 12V windings on them to fudge the output voltage. 
The very expensive one I mentioned earlier is one example With some heavy duty shopping  the price (even with the extra 
windings) can be pretty reasonable. Another option is a 208 to 230 V transformer. Just run it at 120V.

Bob

> On May 1, 2018, at 9:51 PM, drlegendre <drlegendre at gmail.com> wrote:
> 
> Not sure if it's already been mentioned, but you could use a 12V 4-5A transformer to buck-off the extra voltage at the output or input of a 120:120 isolation transformer. Bucked down to 108V, rectified and filtered, you should end up just about where you want to be.
> 
> On Tue, May 1, 2018 at 8:19 PM, <hwhall at compuserve.com <mailto:hwhall at compuserve.com>> wrote:
> Couple ideas:
> 1.  Start out with the isolation transformer idea, find out what the final DC output is when rectified & filtered, cut into the transformer & take off some turns.  
> 2.  Make the above power supply but feed it with a variac instead of cutting up the isolation transformer.
> 
> Wayne
> WB4OGM
> 
> -----Original Message-----
> From: ken Schwieker <ksweek at mindspring.com <mailto:ksweek at mindspring.com>>
> To: GreenKeys <GreenKeys at mailman.qth.net <mailto:GreenKeys at mailman.qth.net>>
> Sent: Tue, May 1, 2018 6:25 pm
> Subject: Re: [GreenKeys] 120vdc at 4-5 amps?
> 
> If you use an isolation transformer you will end up with considerably more than 120 volts dc after rectifying and filtering. One possible solution is to get a variac, remove all the center hardware
> and wind enough turns of insulated wire for the secondary to produce the needed voltage.
> Ken S 
> 
> At 11:13 AM 5/1/2018, you wrote:
> No, I don't need to run 100 loops at once. I have several pieces of gear with 120vdc motors and it would be nice not to have to plug/unplug them one at a time on my 1A supply.
> Any suggestions about where to find a suitable transformer? -Â  Diodes and caps are no problem. I'll keep an eye out at the Dayton hamfest.
> 
> Nick England K4NYW
> www.navy-radio.com <http://www.navy-radio.com/>
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