Wiring a relay switch to power up a machine using remote control?

[Robbiemikeyd]

So this is a question around my woodworking workshop. I have a dust collector which is connected up to various machines around the shop and want to be able to switch it on with a simple remote control I carry with me.

I purchased this relay from Amazon:
QIACHIP Universal Wireless Relay Module 12V 1CH Remote Control Light Switch Receiver RF 433 Mhz with 2 Smart Transmitters for Entrance Control, Car Light 164ft Long Range https://amzn.eu/d/iXQKYmE

As I understand it I believe I can use an old 12v adaptor linked up to the dc input.

And then rewire the dust collector power supply from the mains through the COM and NO.

I'd really appreciate it if someone can just check me on this, or tell me I'm way off the mark and go get learned.

 

[Lucien Nunes]

In concept, yes. Points to consider:

Is the extractor safe to start remotely, e.g. can the impeller be accessed while dismantled for cleaning, requiring local isolation for safety during maintenance to prevent unexpected starts? You do the risk assessment, we can't do it remotely.

Is the relay on the module rated to switch the extractor motor? Ominously, I don't see a rating in the module description, only the silly '1. Maximum input power is 250 V' where of course 250V isn't a power rating. The relay seems to be marked 7A/250V (I can't see clearly) but that would be resistive load unless otherwise marked and not necessarily adequate for 7A of induction motor load.

The module will need mounting in an enclosure with adequate restraint for the cables.

It might not provide strictly compliant creepage distance between the 230V and 12V circuits, so it would be prudent to consider the 12V circuit hazardous live and not electrically separated from the mains.

 

[Carolina]

What about adding a N1 contactor with a 12V DC coil after this relay to let it handle any high currents? I wouldn't trust the relay mains voltage and 7 amps. And a switch to turn off the relay and de-energise the coil.

But something like that would go in a proper circuit, not one built with an old 12v adaptor in mind. Will it work without the contactor and switch? YES. Will it be super safe? no idea.

 

[brianmoooore]

That's the exact same module that I bought a couple of months ago to replace a failing control system on one of my roller shutter doors. Haven't got around to fitting it yet, but when I do, it will do so via a contactor. I very much doubt that the relay is capable of controlling the inductive load of a motor for long.