gonmiguelPI
Posts: 2
Joined: Wed May 28, 2014 2:52 pm

24 VAC electrovalve

Wed May 28, 2014 3:15 pm

Hi, i would like to connect a 24 VAC electrovalve to the raspberry. I saw some pages on the web, but it´s not very clear for me.

Rasperry is 5v (dc)
Electro Valve is 24vac

I have a Relay so that i can connect a GPIO from the raspberry and turn that valve on.

For that what i understand, at this point i need two different power supplies...

Is there anyway to use just one power supply ? Like having a power supply 24VAC and somehow converting it to 5VDC to connect the rasperry pi? I was thinking about dc-dc converter, but the valve and the relay working on ac... Is there any alternative to use just one power supply ?

Thanks everyone :)

Let´s PI !

Relay: (http://www.opto22.com/site/pr_details.a ... em=MP240D4)
ElectroValve: (http://www.irrigationdirect.com/irrigat ... ves/dfv100)

klricks
Posts: 6549
Joined: Sat Jan 12, 2013 3:01 am
Location: Grants Pass, OR, USA
Contact: Website

Re: 24 VAC electrovalve

Thu May 29, 2014 1:20 am

The AC can be converted to DC with a bridge rectifier (4 diodes) and a capacitor:
http://en.wikipedia.org/wiki/Diode_bridge
From the output of that you can connect a 5V regulator. Best to get a switching or 'buck' type regulator.
Maybe something like this:
http://www.dimensionengineering.com/products/de-sw050
Last edited by klricks on Fri Jun 06, 2014 1:51 am, edited 2 times in total.
Unless specified otherwise my response is based on the latest and fully updated Raspbian Buster w/ Desktop OS.

johndough
Posts: 254
Joined: Sun Jan 13, 2013 2:00 pm

Re: 24 VAC electrovalve

Thu May 29, 2014 9:27 am

gonmiguelPI wrote:Hi, i would like to connect a 24 VAC electrovalve to the raspberry. I saw some pages on the web, but it´s not very clear for me.

Rasperry is 5v (dc)
Electro Valve is 24vac

I have a Relay so that i can connect a GPIO from the raspberry and turn that valve on.

For that what i understand, at this point i need two different power supplies...

Is there anyway to use just one power supply ? Like having a power supply 24VAC and somehow converting it to 5VDC to connect the rasperry pi? I was thinking about dc-dc converter, but the valve and the relay working on ac... Is there any alternative to use just one power supply ?

Thanks everyone :)

Let´s PI !

Relay: (http://www.opto22.com/site/pr_details.a ... em=MP240D4)
ElectroValve: (http://www.irrigationdirect.com/irrigat ... ves/dfv100)
Hiya

Yes it is possible.

Rectifying 24 vac to DC will give 24 * 1.41 = 33-34 vdc.

5v regulator will want to drop from about 13v to 5v. There are higher ranges available but beware of heat.

If you get a 12v + 12v @ 30va then perhaps you could series the 12v + 12v to get 24vAC. Then just take the 12v and run the Pi by rectifying and regulating to 5vDC.
The other 12 v winding would power be rectified and regulated for 12vDC to power a relay.

It sounds confusing, and really depends on your choice of transformer.

If in doubt please ask.

gonmiguelPI
Posts: 2
Joined: Wed May 28, 2014 2:52 pm

Re: 24 VAC electrovalve

Fri Jun 06, 2014 12:09 am

Hi again,
i´m sorry that i didn´t reply yet, but as i´m doing this in part time project i had not yet time to read awsers before.

At this moment i´ve got:

1. Power supply 24vdc
2. Relay (http://www.opto22.com/site/pr_details.a ... em=MP240D4)
3. ElectroValve RainBird (JTV)
http://rainbird.com/homeowner/products/ ... V-JTVF.htm


I can get the 5Vdc for the raspberry, but my problem at this time is with the power for electrovalve...
I read some people telling that i can use dc with ac valves, but i dind´t understood how i can get that.


A) Will my relay operate 24VDC ?
B) Can i use this 24VDC to Power my rainbird 24vAC electroValve ?

Thanks a lot for all your time and atention!

johndough
Posts: 254
Joined: Sun Jan 13, 2013 2:00 pm

Re: 24 VAC electrovalve

Fri Jun 06, 2014 9:58 am

gonmiguelPI wrote:Hi again,
i´m sorry that i didn´t reply yet, but as i´m doing this in part time project i had not yet time to read awsers before.

At this moment i´ve got:

1. Power supply 24vdc
2. Relay (http://www.opto22.com/site/pr_details.a ... em=MP240D4)
3. ElectroValve RainBird (JTV)
http://rainbird.com/homeowner/products/ ... V-JTVF.htm


I can get the 5Vdc for the raspberry, but my problem at this time is with the power for electrovalve...
I read some people telling that i can use dc with ac valves, but i dind´t understood how i can get that.


A) Will my relay operate 24VDC ?
B) Can i use this 24VDC to Power my rainbird 24vAC electroValve ?

Thanks a lot for all your time and atention!
Hiya

I said to use the 24 ac for the valve.

Take a second pair or 24 AC and rectify and regulate to get 5v DC.

But starting with a 24 DC complicates matters to get 24 AC
(At this moment i´ve got:

1. Power supply 24vdc)

So could you link to the transformer / PSU please.

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