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3 Position switch - how does this work?

soma

Apr 7, 2016
8
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Apr 7, 2016
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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.
2yoomfq.jpg

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.

etd3b4.jpg

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
2rh42ef.jpg
 
Last edited:

(*steve*)

¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd
Moderator
Jan 21, 2010
25,510
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25,510
ok, reading your images again, this switch cannot be used since, rather than having a "both off" position it had a "both on" position.
 

ramussons

Jun 10, 2014
462
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Jun 10, 2014
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462
Can we have a photo of the switch and the Terminals layout?
 

soma

Apr 7, 2016
8
Joined
Apr 7, 2016
Messages
8
ok, reading your images again, this switch cannot be used since, rather than having a "both off" position it had a "both on" position.


This happens in both my "on" positions, while the "off" position is unafected and works as it should.
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
f1w95f.jpg


This is the wiring/situation shown in my second diagram, however only one of the "power sources" is wired in.
19pflx.jpg

2ic8l5l.jpg

t4za1d.jpg

Here it is on ebay: http://www.ebay.co.uk/itm/182186184574?_trksid=p2057872.m2749.l2649&ssPageName=STRK:MEBIDX:IT
 
Last edited:

soma

Apr 7, 2016
8
Joined
Apr 7, 2016
Messages
8
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.
 
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