26VDC power, 12VAC output?

  • Hi all – I'm looking to control a legacy gate solenoid hopefully with a Shelly Uni.

    At the gate the existing control module has 26VDC power which I can tap into, and the existing control outputs a 12VAC signal to trigger the gate lock.

    Will a Shelly Uni be able to output 12VAC, assuming it's being powered by 26VDC? Thanks!

  • Indeed, a Shelly UNI may be powered with 26V DC. But the maximum current driven by each output of the UNI is 100mA. I assume the current needed by the solenoid will be higher. This must be objective of an investigation by measurement.

    „Habt Geduld. Alle Dinge sind schwierig, bevor sie einfach werden!“ (aus Frankreich)

    „Nothing in life is to be feared, it is only to be understood.“ (Marie Curie, 1867-1934)

    „Es reicht nicht“, rief Schiller, „Gedankenfreiheit zu fordern, man muß auch denken können, sonst fordert man Gedankenlosigkeitsfreiheit und die ist die Freiheit zur Dummheit, welche wiederum die schlimmste Unfreiheit überhaupt ist!“
    (Aus „Besuch aus Weimar“ von Gert Heidenreich, Schriftsteller, *1944 in Eberswalde)

  • Indeed, a Shelly UNI may be powered with 26V DC. But the maximum current driven by each output of the UNI is 100mA. I assume the current needed by the solenoid will be higher. This must be objective of an investigation by measurement.

    Many thanks for confirming! I'll investigate the solenoid further, the sticker on it says 12VAC and I think 15W, which I assume is the maximum rating.

    My second option is installing the Uni inside the phone unit and use it to close the small momentary switch (bottom right in this photo). Triggering the switch would force the control module to provide the 12VAC necessary to activate the solenoid.

  • 15 W at 12V AC gives more than 1 ampere! You’ll need a relay to drive the solenoid.

    „Habt Geduld. Alle Dinge sind schwierig, bevor sie einfach werden!“ (aus Frankreich)

    „Nothing in life is to be feared, it is only to be understood.“ (Marie Curie, 1867-1934)

    „Es reicht nicht“, rief Schiller, „Gedankenfreiheit zu fordern, man muß auch denken können, sonst fordert man Gedankenlosigkeitsfreiheit und die ist die Freiheit zur Dummheit, welche wiederum die schlimmste Unfreiheit überhaupt ist!“
    (Aus „Besuch aus Weimar“ von Gert Heidenreich, Schriftsteller, *1944 in Eberswalde)