Switch to change between three different power sources

[OneZ]

Greetings,

In my friend's house they have three different power sources:
Main
Generator
Inverter + Batteries

There is already a switch that does the following: in position 1 it make lights work on Main, on position 2 it makes light works on Generator. Can someone explain how is this switch connected with wires ?
How can I make/convert this switch to include the third power source ?

Thanks.....

 

[OneZ]

So is this for a building, or a boat or other such recreational vehicle?

For thier house. Electricity goes down here for up to 16 hours a day.....

 

[Deleted member 9648]

Only other way I can think of is to have the mains input through a dropout contactor and then bring in the other supplies through a manual changeover switch when mains failed.You would have to wire the contactor coil through a link of some sort to the changeover switch so that when mains came back on the contactor could only be reset manually with the changover switch in the off position.

 

[JD6400]

Only other way I can think of is to have the mains input through a dropout contactor and then bring in the other supplies through a manual changeover switch when mains failed.You would have to wire the contactor coil through a link of some sort to the changeover switch so that when mains came back on the contactor could only be reset manually with the changeover switch in the off position.

I know it is not in the UK but i think it would be a lot safer to have a secondary change over switch , at least then you can guarantee safe isolation at all times .

 

[Deleted member 9648]

I know it is not in the UK but i think it would be a lot safer to have a secondary change over switch , at least then you can guarantee safe isolation at all times .

Could be...how would that be wired though?

 

[JD6400]

This may take me awhile to explain ( one finger typing !) so may not post back for a bit !

 

[Deleted member 9648]

This may take me awhile to explain ( one finger typing !) so may not post back for a bit !

Leave you to it mate....brain disengaged temporarily...partaking of refreshment.

 

[JD6400]

If the house is on the load side of the original change over switch , i would take mains in on supply side number one and on supply side number two take the load side of the new change over switch .

Bearing in mind that the load side of this new change over switch goes into the number two supply side of the existing change over switch , now feed this new switch with the inverter on supply side number one and the generator on supply side number two .

I can see why you like the contactor idea but we attend at least half a dozen break downs a year in grain stores and the like where a contactor will have failed in the energised position thus often holding it in .

 

[JD6400]

Leave you to it mate....brain disengaged temporarily...partaking of refreshment.

About to do the same !!!:17:

 

[Deleted member 9648]

Yep...better idea all round.

 

[JD6400]

Why , thank you kind sir !:blush2:

 

[Engineer54]

There is another way, with a standard auto changeover switch, by using a UPS, the main power supply running through the UPS. When the power fails the batteries take over the load until the generator runs up to speed and the auto change over switches to generator power. Basically the same system used in hospital medical Operating rooms/suites. One things for sure, whatever way these 3 power systems are incorporated into an installation, it isn't going to be a cheap exercise!! lol!!

 

[Engineer54]

What i'm saying above is that the UPS battery power is only used as a short interim power source, between main and stand-by generator supply. It wouldn't really be feasible to run a household needs on battery power, you would need a hell of a lot of batteries to do that anyway.

On medical rooms that use the above UPS system, ...performs both as an interim power source and as a fail safe supply if the generator fails to start, or fails during operation while the main supply is still out. But then the battery storage is rated to give a 3 hour duration, plenty of time for the surgeons to make the necessary arrangements to the unfortunate patient on the table ...lol!!