I'm trying to use a single 120v contactor to control a dpdt relay to. I want the on state to power one wire and the off state to power another wire, with the negative wire being the common wire that's always powered. The point of this is to control a motorized 3 wire valve for autonomously watering some plants. When opened it will water the plants and when closed it will not. (This is the intention anyway.) Please help me figure out what I'm doing. I'm thinking
2 separate 12v power supplies
One powering the closed wire all the time on the normally closed and powered side of the 12v relay, and another that turns on when the contactor turns on that some how automatically turns off the other one.
I'm not sure which relay to use to make this work and would actually prefer not to get two separate power supplies and make it work with one. Also it's really not possible to add another contactor there for reasons involving space and getting another waterproof contactor that's expensive.
Can someone offer some advice as to what I should do? Because I'm only 50% sure I know what I'm doing here. Everything else is done and I really want this working so my mom doesn't have to do it.
She's old af.
I do not see an Arduino or similar in the problem. You know more than I do. How about a simple sketch and links to technical information on the valves. Normally the - is not switched, to keep it more understandable can you switch the positive side? What is connected to the contactor? Some contractors have or can have added external contacts for control. Without knowing what you have there is no way I can give you an accurate answer.
In your sketch show what is powered by what and if there is outlets on the switched side.
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Do you have a link to your proposed solenoid? I am not getting why 3 wires verse two for just turning water On or Off? My thinking is using a simple water solenoid and a simple SPST relay driven by your uC. Why a 120 VAC contactor in this? You have a 120 VAC contactor driving a DPDT relay which I don't understand. This would go much, much better if you post an attempted schematic or drawing.
Automated watering systems are common based on soil moisture level or time and usually for example if I water every two days and want to have water on for a set time.
I'm going to make some assumptions and then some comments....
I assume the contactor is simply on/off and it goes to the relay coil, which is 120VAC.
I assume the relay contacts are connected to 12V and the solenoid valve (which won't work completely).
I assume 12V between one solenoid connection and common turns the water on. Then after you remove power it stays-on until you apply 12V between the other connection and common, and then it latches the water off.
So the contactor has 2-states (and the relay has 2-states) but you want three states/actions...
1 - Turn the valve on
2 - Turn the valve off
3 - Turn off power to the solenoid so it holds the current state.
If all of that is correct, you need three separate relays.
One to isolate the 120V contactor voltage and sense if it's on or off. This relay needs a 120V coil (with 5V on the contacts for the microcontroller). It can be SPST (or more).
You need another relay to turn on & off the 12V to the solenoid. This one can have a 12V coil and again it just needs to be SPST (or more).
The last relay determines which of the valve connections is being used and this one has to be SPDT (or more). Again, probably with a 12V coil.
And you need a microcontroller (or some kind of logic/timing circuit) to temporarily activate the solenoid whenever the contactor changes states.
The Arduino can't directly power a relay coil but there are "relay boards" with a driver circuit that drives the relay coil with 5 or 12V at more current than the Arduino can directly supply.
I'm not great with schematics I was actually not even using an Arduino board however this seemed kinda like the perfect people to help because it's a sub component of other Arduino things you can make. In this case substitute the Arduino with a z wave direct wire relay by ge.
Couldn't I have one side of a dpdt relay power one 12v adapter on the open circuit, while the other side disconnects another 12v relay connected to the close motorized valve circuit? It stops by itself when fully opened or closed(the valve)
OK so you have a motorized valve? Not a standard solenoid valve to turn water On or Off? Yes, some motorized valves have built in limit switches. OK I get that. Do you have a link to the actual valve, like maybe a data sheet? How are you planning to activate or deactivate the relay? What is going to make watering start / stop?
Motorized Ball Valve- 3/4" Brass Electrical Ball Valve with Standard Port, 9-24V AC/DC and 3 Wire Setup by U.S. Solid https://a.co/d/dwX25QP
Here's the valve
Enbrighten Z-Wave Plus 40-Amp Indoor/Outdoor Metal Box Smart Switch, Direct Wire, 120-277VAC, for Pools, Pumps, Patio Lights, AC Units, Electric Water Heaters, Gray, Z-Wave Hub Required, 14285 https://a.co/d/3qRsIir
Here's the contactor/relay activating i
Open when on or deactivating it and activating closed when of.
Anyone know of a 12v version of this? I have it all stuffed in a Tupperware container that I'm gonna seal with silicone if I can't find a smaller one to put in something smaller. Don't line having to run 120v live wire from the direct wire relay/contactor to a Tupperware container. Rather 12 in a smaller box with a few relays. Just not sure how to.
