Author Topic: Whole-house fan controler - need a relay capable of 5.9A (120V)  (Read 3048 times)

nfriedly

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Hi everyone,

I'm building a replacement controller for my whole-house fan, and I have a couple of questions:

* The digispark relay shield is only rated for 3A@125VAC, but my fan motor says it's 5.9 amps (115v). Can anyone recommend an alternate relay that's a little more beefy? And would I be able to just swap out the relay on the digispark shield or is the rest of the shield also unable to handle the increased power draw?

* I'd like to have everything fit inside of the 2-gang square electrical box that houses the current broken fan controler, but I'm a little unsure how to handle power. I know I could just plug in a wall wart somewhere outside the wall and run the wire to inside the wall, but that seems a little silly. Is there a good way to make this work entirely inside of the electrical box?

robmack

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Re: Whole-house fan controler - need a relay capable of 5.9A (120V)
« Reply #1 on: October 04, 2015, 04:54:40 am »
Bit late now maybe, but you could attach the output of your whole house fan controller to an external 120V relay that has a greater power handling capability than the Omron onboard the shield.  The coil of the external relay will connect in series with the header on the shield.  The contacts will connect to the fan.  Choose a relay with contacts rated for inductive loads and with a current capacity of 15A.

nfriedly

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Re: Whole-house fan controler - need a relay capable of 5.9A (120V)
« Reply #2 on: October 04, 2015, 05:00:14 am »
Yea, I ended up with one of these: http://www.digikey.com/product-detail/en/AQA211VL/255-2977-ND/2364682 which seemed to work well in my testing... But I had some bugs in other parts of my design and then we had a baby... So I reassembled it with the old switch and never got back to finishing the project.