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3 Position switch - how does this work?

Discussion in 'General Electronics Discussion' started by soma, Jul 5, 2016.

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  1. soma

    soma

    8
    1
    Apr 7, 2016
    I have a 3 Way AC rotary switch - and dont really know how it works.

    I need to wire a 3 position AC 240v switch, which will swap between 2 separate power sources, and an off position.

    The problem: the 2 power supplies must lead to the same appliance/load, while never both supplying simultaneusly.

    All diagrams show the same position switch.
    [​IMG]
    power sources are separate at the "AC IN" side of the switch

    I want them combined together at the "AC OUT" side of the switch, so the appliance/load stays the same while the power source can be changed using the switch. The problem: when I combine/connect the terminals at the "AC out" side of the switch, the switch no longer works! current is able to flow in and out of the switch through ALL 4 terminals/poles rather than just 2.

    This happens in both my "on" positions, while the "off" position is unafected and works as it should.

    [​IMG]
    If i do not combine the "AC out" terminals, the switch works as it should; only the appopriate 2 poles/terminals allow current through (the first diagram).

    This 3rd diagram shows how i expected the switch to work
    [​IMG]
     
    Last edited: Jul 6, 2016
  2. (*steve*)

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

    25,418
    2,788
    Jan 21, 2010
    ok, reading your images again, this switch cannot be used since, rather than having a "both off" position it had a "both on" position.
     
  3. ramussons

    ramussons

    367
    71
    Jun 10, 2014
    Can we have a photo of the switch and the Terminals layout?
     
  4. soma

    soma

    8
    1
    Apr 7, 2016

    This means I have a "both off" position, and a "both on position", but not a "one off" or "one on" position.

    Pics of my switch
    [​IMG]

    This is the wiring/situation shown in my second diagram, however only one of the "power sources" is wired in.
    [​IMG]
    [​IMG]
    [​IMG]
    Here it is on ebay: http://www.ebay.co.uk/itm/182186184574?_trksid=p2057872.m2749.l2649&ssPageName=STRK:MEBIDX:IT
     
    Last edited: Jul 6, 2016
  5. soma

    soma

    8
    1
    Apr 7, 2016
    WOW, i am very silly indeed... I just found out my input and output need to be swapped! I put the input at the even numberd side (2, 4, 6, 8) while they should be at the odd numberd side (1, 3, 5, 7). This way it works as i expected it to when the 2 outputs is linked into one output.
     
    (*steve*) likes this.
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