I need to plug two different sources of power into product (if exist) and this product change the power source automatic if the main source down to the second one.
I need the name and the brands if possible lot of thanks.
Diogo Serruya

Are you talking about a battery-backed up power supply? Power normally comes from the power grid, but in the event of a power failure, it comes from battery storage?

Google "uninterruptible power supply"
Let me google that for you (http://www.lmgtfy.com/?q=Uninterruptible+power+supply&l=1)

There are also automatic generators that will kick in when a power failure occurs. I'm familiar with Generac, but I'm sure there are other brands:

http://www.generac.com/Default.aspx

We need some info like DC, AC, Voltage, Current, power, # of phases?

Any chance your looking for a rack mounted trasfer switch?

Rack Automatic Transfer Switches (http://www.datacenterresources.com/Racks/Rack_ATS.asp)

More detail of what your situation is and what is needed will be helpful.

# of phases.
Thx!

tkrussell thanks for the answer its start point for me great.
Now I need to see other option loot of thanks.