[GreenKeys] inexpensive loop supply transformer wanted

[Ed Sharpe]

Some one needs to get with it and build a group for sale at a reasonable price... usb in... 20 & 60 mil out

Ken Schwieker <ksweek at mindspring.com> wrote:
>If you don't want the approx 160+ volt loop supply with some of the 
>problems associated with that high of a supply there are inexpensive 
>lower voltage transformers available.
>
>Here is the info I posted about this particular transformer some time 
>ago. These transformers look to be well made and most likely in US.
>
>Just a heads up on a source of very reasonably priced transformers 
>suitable for loop supplies.
>Can be used to construct a supply with a somewhat lower and safer 
>voltage than the usual 140 volt or higher ones.
>Did some tests, primary at 120 v;
>74 v ac no load
>70 v ac with 100 ohm load (700 ma)
>One hour with 100 ohm load connecter, transformer temp 110 F (ambient 
>about 70 F).
>Size,  3" x 2 1/2" x 2 1/2" high not counting chassis mounting tabs. 
>Mounting holes 3 1/2" between centers.
>Only two terminals on the bottom (pri) and three on the top (center 
>tapped secondary) are used.
>I purchased 3 and the total was around $25 including shipping
>
>http://www.apexelectronic.com/TR5-W-26
>
>Ken S
>
> >At 11:56 AM 12/20/2013, you wrote:
>I'm working on a small project to have a Single Board Computer such 
>as a Raspberry Pi or Arduino drive my TTYs (Model 15 at 45 WPM and a 
>28 RO at 75 WPM) with some canned messages from memory.  As part of 
>that effort I'd it to have it's own loop supply (120VAC to 120VAC 
>isolation transformer, bridge rectifier, filter cap, 2800 ohm 20 watt 
>limiting resistor).  Does anyone have suggestions on where I might 
>find a low cost isolation transformer for this purpose?
>
> >Paul Newland, ad7i
>
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