Recommendation for switching a 12vdc 1A load with 120vac

Thread Starter

rmarkin

Joined Nov 27, 2016
4
Hello all,
This is my first post on AAC and I will try to make it succinct.

What I wish to accomplish:
I would like to safely switch a 1A 12vdc fan motor on/off when a 120vac signal is active/inactive.

Research:
My first thought is to use something like this http://www.opto22.com/site/pr_details.aspx?cid=4&item=120D3 relay but it is unclear to me whether it can switch with 120v and control 12v and whether or not it is the best way to do so.

More detailed description:
In a 25' cabin cruiser, I have a small refrigerator that runs off of an inverter from the 12v batteries in the boat. The fridge will always, (unless the main perko switch is off), have 120v going to it's control board but will only engage it's compressor when necessary. Due to the tight installation requirements, there is not much room for natural air flow across the cooling coils of the fridge. I would like to tap in to circuit that runs the compressor and engage a cooling fan, (run directly from the batteries for efficiency), to cool the coils.

Any thoughts or observations would be greatly appreciated!

Robert
 

crutschow

Joined Mar 14, 2008
23,533
That relay is for switching 120Vac from a DC control voltage, so won't work for you.

The easiest is to use a mechanical 120Vac coil relay.

All solid-state relays operate from a low voltage DC control signal (such as this) so, if you want to go solid-state, you will need to make a small rectifier circuit to convert the 120Vac to DC.
If you want to go that route I can show you how to do the rectifier circuit.
 

Thread Starter

rmarkin

Joined Nov 27, 2016
4
That you for the reply Sir.

I have no preference over solid state or mechanical, as long as the mechanical has a decent life span. (I truly don't envision more than a few hundred cycles per year).

What would you recommend for a mechanical coil relay?

Robert
 

MaxHeadRoom

Joined Jul 18, 2013
19,198
For that low current you can select from several termination styles, there is pins for printed circuit, plug in type for screw terminal sockets, and spade terminal or push on connectors.
For that low a degree of current you should have no problem finding one in any configuration.
Search OMRON, TYCO, IDEC etc for just a few manuf.
Max.
 

Thread Starter

rmarkin

Joined Nov 27, 2016
4
Thank you guys very much! I think I have just enough information now to be dangerous (yet cautious) :)

Have a great day!

Robert
 
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