X10 Community Forum

🔌General Home Automation => Automating Your House => Topic started by: bitman on April 28, 2009, 11:06:41 PM

Title: 24VAC Water Valves.
Post by: bitman on April 28, 2009, 11:06:41 PM

Hello all.

Winter is finally loosing it's grip in the Colorado high country and I can see lots of grass.
Knowing that no way am I going to run my hose end traveling sprinkler without x10 control this year, I just got back from a 70 mile run to Home Depot where I bought an Orbit 24VAC water valve.

So, 24VAC hu.

Does AC really go directly to the solenoid or is it rectified first, using AC because of it's ease of transmission over distances? AC seems so inconvenient and I find it curious that it is the standard. Can someone enlighten?

I have a plethora of 19.5 VDC transformers from notebook pcs. Does anyone know if it is ok to send DC to these units?

Thanks in advance.
:Ron

 

Title: Re: 24VAC Water Valves.
Post by: JeffVolp on April 28, 2009, 11:50:59 PM

It is 24VAC, which has been the standard since way before notebook computers.

You should not feed DC to the valve's solenoid.  AC current is limited by the solenoid's inductance.  DC current would only be limited by the winding's DC resistance.  It would probably burn out very quickly if you fed it with DC.

I am puzzled why you find AC "inconvenient".  Just buy the appropriate 24V transformer, connect two wires, and plug it in.  You don't even have to worry about polarity.

Jeff

Title: Re: 24VAC Water Valves.
Post by: bitman on April 28, 2009, 11:57:45 PM

Oh because I have DC transformers around and would have to buy a AC one I suppose.  ;)

What kind of current capability should I look for in a 24VAC tranny?

Title: Re: 24VAC Water Valves.
Post by: JeffVolp on April 29, 2009, 12:24:34 AM

Quote from: bitman on April 28, 2009, 11:57:45 PM

What kind of current capability should I look for in a 24VAC tranny?

It depends on how many valves you need to switch on at the same time.  As I recall, the smaller sprinkler transformers are 10VA (.4A), and are meant to power the controller and a single valve.  The larger 20VA transformers (.8A) can power at least two valves at the same time.

Jeff

Title: Re: 24VAC Water Valves.
Post by: bitman on April 29, 2009, 09:02:05 AM

Thank you.

Just one.

I'm looking forward to x10ing my traveling sprinkler. On more than one occasion during any given summer I have tucked into bed around 10:00 pm and just before drifting off to sleep, remembered that the sprinkler was on and fixing to run away down the street. So I would go out in PJs with a flashlight, walk around on the wet grass to get to the valve on the side of the house. One time I got up it the morning to find it was headed off into the forest only held back by the weight of it's hose it was dragging.  ::)

That thing is going to shut off every night at 10:00.  ;D

Yes, I'm an idiot.