220v switching Relay?
Dixon
Edited Having read your comment describing what you are actually doing and want, BillRussel has correctly commented on how to do this with one SPDT relay or a SP (NC) relay, whereby the mains powers the coil and the inverter feeds the fan via normally closed contacts. Note that "normally" means no power to the coil. However, I suspect that you will ultimately want more control over the fan, such as turning the fan off when using the inverter (eg you are in another room, it is cold etc.) or indeed turning the fan on when the mains is available (eg just using the fan and not the A/C). Define Automatic operation as fan off when mains is present, fan on when mains fails. Define Manual operation as when you can turn the fan on/off yourself right now with an on/off switch. There is then a light switch unit with two switches. One switch selects between automatic and manual operation. The other switch is the on/off for manual operation (regardless of mains present or not). I don't know the US terminology properly but this type of light switch is basically a downstairs hallway switch, ie one SPST switch (for the hallway) and one SPDT (for joint control of a landing light). Failing that, it can be a "two gang three way" ie DPDT with one unused terminal. The Relay is DPDT.
billrussell42
use some logic (XOR) before the relay, then a simple SPST relay would work. What are the input voltage? or 3 relays wired together. see schematic below. You can eliminate the extra contacts on the left if the controls are DC, just use two diodes. edit: for some reason Yahoo is distorting my drawing. I'l try again.
frank lynn
You need an Exclusive OR (XOR) function relay. Standard relays do not have this kind of built in logic. There are quite a few schematics on how to build one that require at least two, if not three, relays to perform the function you desire.
Steven
Just wire two spdt relays like a stairway "three-way" switches. ie connect NC to NO on the other relay, NO to NC, and then the two "poles/C" connect when only one relay is activated.
Bob
You need to control it with an EXCLUSIVE OR gate.
lee26loo，異域秦後人
All relays have just one input !! To do your task, using logic " 2 input AND gate " can do.