Andrei S Posted January 6 Share Posted January 6 Hello. I bought a Shelly 3EM to monitor my energy consumption and use it as an input for a contactor to cut off the power whenever the voltage move above a certain level. I also bought a 32 A three phase contactor that I want to use combined with contactor control. Now... I've measured the voltage between I and O pins, but none of the gives me 230V. How can I connect the 230V contactor coil to my Shelly 3EM? Also, that turn on/turn off button should make it turn on and off contactor coil,right? Thanks! Andrei. Quote Link to comment Share on other sites More sharing options...
Members thgoebel Posted January 6 Members Share Posted January 6 Andrei, Pins I and O of Shelly 3EM are the contacts of a relay! Thus, you’ll have to connect the live wire to pin I, one end of the relay coil to pin O and the other end of the coil to neutral. Don’t forget to install a snubber (R/C combination) across the relay coil! Good luck, Thomas 1 Quote Link to comment Share on other sites More sharing options...
Andrei S Posted January 6 Author Share Posted January 6 Ohh, ok. I'm used with sonoff devices with live output. So it's an open contact that will close whenever I turn on/off that internal relay. I'll try this, thanks! Quote Link to comment Share on other sites More sharing options...
Andrei S Posted January 6 Author Share Posted January 6 (edited) @thgoebel Is the snubber really necessary? Edited January 6 by Andrei S Quote Link to comment Share on other sites More sharing options...
Members thgoebel Posted January 7 Members Share Posted January 7 Give it a try and test it without snubber. But don’t blame me if the Shelly is restarting frequently… Quote Link to comment Share on other sites More sharing options...
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