[GreenKeys] Loop supplies

[epvgk at limpoc.com]

On Tue, May 17, 2016 at 07:18:01PM -0400, Ralph Mowery wrote:
> While I have not tried them, ebay has some modules from China that might
> just work for a local loop.  Buy one of the modules which is just a circuit
> board and look around for a 24 volt wall wart DC supply.  The modules are
> only about $ 2 to $ 6.  Some of them can be adjusted for a constant current
> and should be able to put out about 20 volts for the 60 ma loop.
> 
>  

You should be able to use one of those with my CL adapter board, but you'll need
a small current limiting resistor as the board already puts 187 ohms total in 
series with the loop. (plus the dc resistance of the selector magnet coils, etc)

eric

> 
> I have played with a couple of just the voltage regulated supplies.  If you
> need to measure the current, then a low cost ma meter or even one of the
> 'free' ones from harbor freight could be used.
> 
>  
> 
> Here are some of the ebay  links.
> 
>  
> 
> http://www.ebay.com/itm/191015464867?_trksid=p2060353.m1438.l2649
> <http://www.ebay.com/itm/191015464867?_trksid=p2060353.m1438.l2649&ssPageNam
> e=STRK%3AMEBIDX%3AIT> &ssPageName=STRK%3AMEBIDX%3AIT
> 
>  
> 
> http://www.ebay.com/itm/191015464867?_trksid=p2060353.m1438.l2649
> <http://www.ebay.com/itm/191015464867?_trksid=p2060353.m1438.l2649&ssPageNam
> e=STRK%3AMEBIDX%3AIT> &ssPageName=STRK%3AMEBIDX%3AIT
> 
>  
> 
>  
> 
> I would like to have a much higher voltage, but should be ok to run around
> 20 to 24 volts on a local loop.  You might even be able to get some of the
> modules to boost the 5 to 12 volt supplies to 30 volts or so.  Sort of a
> design waste, but  not very expensive either if you have some low voltage
> wall warts.  Then all  you need is a plastic box to put them in and maybe
> some phone jacks.  
> 
>  
> 
> I used a large empty pill bottle to put the computer to machine converter
> board in.
> 
>  
> 

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