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How to increase the current capacity of an XM17A or similar addressable PS?

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HA Man:
I need the functionality of an XM17A or similar X10-addressable DC power adapter (such as XM13A, XM16A, etc.), but need more current capacity.  (I would like to control surveillance cameras having IR illuminators, which can draw up to 500mA @ 12vdc).

Those XM addressable DC power adapters have a number of possible applications, so it's a shame that they have been discontinued.  :(

Anyway, does anyone have any idea whether there is any practical way to produce higher currents, with the full X10 control functionality of the XM device, including the mutually-exclusive action within four-unit-code groups?  If so, how?

I considered trying to rig up some sort of relay on the output of a conventional high-current DC power adapter, with the relay being controlled by an XM power adapter, but that turned out to be problematic operationally - not to mention being surprisingly expensive, and taking up twice the number of AC receptacles.
 
I also considered using an Appliance Module controlling a conventional DC power adapter that has the required current output - unfortunately, the "mutual-exclusivity" of units in the four-unit-code "group" is not provided by the Appliance Modules.

So, I even wondered if an Appliance Module could be modified so that it could be controlled by an XM module (rather than directly by the X10 signal), in order to plug in a higher-capacity DC adapter, while retaining the XM's full X10 control functionality.  But, that gets to be quite kludgey - not to mention using twice as many AC outlets!

So, at this point, I'm stumped and fishing for any practical ideas...

Thanks in advance!

Brian H:
The Appliance Module modification could be a safety issue.
They have a power line derived power supply and the AC Line maybe the common DC buss. Any external wiring could be 120 volts above safety ground.

Maybe a small DC controlled solid state switching module could be used to control the higher current DC you need. From the X10 switched output of the XM17A or any of the other X10 camera power supply models. As the solid state switching modules don't take a great amount of control current.

If I see anything of interest more information can be added.

If you decide on a relay. It maybe advisable to have a back biased diode across the relay coil. So when you turn it off. There is not a inductive spike on the controlled voltage connection.

Brian H:
I found this on the All Electronics web site.
http://www.allelectronics.com/make-a-store/item/srly-2402/1.5-amp-solid-state-relay/1.html

It can be controlled by the switched 12 volts from a XM17A to switch  AC power to a higher power wall wart.
It is rated for 240 VAC but I did not see a minimum AC voltage needed to switch On and Off. So 120 volts AC should also be OK.
Control voltage 9 to 16 volts DC with a maximum DC control current of 16mA.

Would require you to do some custom assembly and wiring.
Others may have an easier or smoother method.

I don't know if a resistor or zener diode could be used to drop the switched 12 volts from the XM17A to the 3-10 volts DC needed to control this Crydom module. It can switch a DC voltage directly On and Off.
http://www.allelectronics.com/make-a-store/item/srly-63/3a-solid-state-relay-for-dc-loads/1.html

HA Man:
Actually, my first thought had been to use a solid state relay on the output of a 500mA DC supply, controlled by the output of the XM module.  But, I kind of shied away from that for a couple of reasons:

* All of the SSRs that I found at the time were quite expensive (much more than the 1.5A device that you found)
* It looked like the arrangement would require a lot of special design work - that's a bit beyond my knowledge level
* The "packaging" of the add-on components looked like it would be difficult and rather costly
That led me to look for alternatives - such as using the Appliance Modules (to switch conventional DC adapters) in place of the XM power modules.  That should work, and would be relatively straight-forward to implement, but wouldn't turn off the other multiplexed camera(s) when another gets switched on...

I wonder if there is some way to emulate the XM's mutually-exclusive operation using Appliance Modules.  Probably could be done with AHP, but probably would need to "commandeer" the monitored House Code in order to track which camera is on.  <Sigh!  ::)>

A different approach would be to use the XM outputs to switch only the video signals from the cameras - but I'm not really sure what sort of switching device would be suitable for multiplexing the video signals... and one big disadvantage with this scheme would be that all power supplies would remain on all the time, wasting energy.

I dunno... it's seeming like there is some kind of significant gotcha no matter how I approach this.  :-\

Brian H:
I am not an AHP expert but it maybe able to emulate the mutually-exclusive action. Using Appliance Modules.

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