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Thread: Possible to use NC/NO switches as 3-way switches?

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    thevillageinn's Tools

    Question Possible to use NC/NO switches as 3-way switches?

    Hello everyone,
    I'm trying to learn whether I can wire up a couple NC/NO switches to act like household 3-way switches on a gate controller? I tried as many combinations as I could guess at the other day and wasn't successful.

    The back story:
    Where I work we have a privacy gate to the entrance of the property and while we have a strobe sensor to open it, it also has a bypass key switch which the local sheriff and fire departments can use to open the gate. They have a key to that switch - I do not. I can open the panel the switch is installed in and access the wiring and rear of the switch. The key switch seems to be a NO/NC switch with 2 of the 3 pins connected to the gate controller board. Should the responders use the key bypass they usually leave without closing the gate - then we need to wait until they make a trip out to close it - which is a waste of time and effort.

    I'd like to have a second switch which would essentially swap the state of the key switch and allow it to function for them and close the gate for me...which is why I am likening this to a household 3-way switch setup.

    Any thoughts on this? When I was somewhat successful, I could get my second switch to reconnect the circuit but the first switch would not open it again.

    Thanks for any assistance.

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    Sleykin (09-16-2020)

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    A gate controller normally uses a momentary switch to cycle it to the other end of its range. At least that's the way the emergency services switch seems to be connected, and that is how the remote receivers are hooked up.

    A factory installed switch may use a directional switch with NC/NO/NC spring return to center. All it is doing is bypassing the reversing function in the control circuit.

    If all you want to do is cycle it closed or open, just put a momentary switch across the two wires on the emergency services switch.

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    Sleykin (09-16-2020), thevillageinn (09-14-2020)

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    thevillageinn's Tools
    Ah yes, the controller does use the momentary. But I guess I should have been clearer that this switch is attached directly to the opener not the main controller and it stays in the open or closed position so while a momentary could trigger it - the switch has opened (or closed) the circuit. Theoretically, I could add an extra wire to the switch which I could then manually swap inside the gate opener but I donít know how clear the conduit is between the post where the switch is and the opener panel and I also canít easily assign a non-technical person to restore the gate.

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    Try downloading an install manual for the gate operator.

    It sounds to me like a momentary switch should have been used for the emergency services key.

    Try disconnecting one wire from the switch then touching it back again and see if the gate closes, if so then it needs a momentary switch, or an instruction on the panel to return the switch to the off position after the gate opens.

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    If you find out that you still need to change the switch state to close the gate, try this diagram for a staircase light....
    Possible to use NC/NO switches as 3-way switches?-switch-diagram.jpg

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    Sleykin's Tools
    If the control voltages is DC you could use steering diodes to let the switches be isolated from each other. A couple pictures would be good. On our gates at the airport (before they got all crazy) The gates would unlock on power failure and you could just push them open. When power came back the gates would close. Some pictures of the control box and the switch box might be good if you want specific info. Or, call the manufacturer...

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    thevillageinn's Tools
    First, thanks for the replies. The diagram makes it seem simpler than what I had been looking at previously so hopefully I was just confused.

    Unfortunately, I forgot to bring my test switch setup home with me so I haven’t had a chance to test anything recently.

    The main controller ( doorking 1836 or something like that) has no knowledge of the gate opener’s (elite something - I’ll have to open it and look at the board) position as far as I know.

    I just was hoping that swapping the state of the two wires returning to the opener would be simple and I could add another key switch for the rare occasion that the sheriff uses their key and doesn’t close it.

    I’ll look up some details on the opener because it doesn’t seem as though it’s acting on a momentary signal though it may well respond to momentary on these terminals although when the key switch is turned it’s turned and the key is able to be removed. I’ve heard they like to leave it open while on scene for other responders who may need to enter but that could just be conjecture.

    Thanks again!

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    Quote Originally Posted by thevillageinn View Post
    Hello everyone,
    I'm trying to learn whether I can wire up a couple NC/NO switches to act like household 3-way switches on a gate controller? I tried as many combinations as I could guess at the other day and wasn't successful.

    The back story:
    Where I work we have a privacy gate to the entrance of the property and while we have a strobe sensor to open it, it also has a bypass key switch which the local sheriff and fire departments can use to open the gate. They have a key to that switch - I do not. I can open the panel the switch is installed in and access the wiring and rear of the switch. The key switch seems to be a NO/NC switch with 2 of the 3 pins connected to the gate controller board. Should the responders use the key bypass they usually leave without closing the gate - then we need to wait until they make a trip out to close it - which is a waste of time and effort.

    I'd like to have a second switch which would essentially swap the state of the key switch and allow it to function for them and close the gate for me...which is why I am likening this to a household 3-way switch setup.

    Any thoughts on this? When I was somewhat successful, I could get my second switch to reconnect the circuit but the first switch would not open it again.

    Thanks for any assistance.
    Yes these can be used as 3 ways ,you must use common of one switch as power,common of other switch as load and the no and nc become travellers ( they get connected together . eg nc to nc , no to no.THis will complete the wiring for a 3 way switching ciruit.


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