Hi.
I'm having a few problems to understand the backup rule, say something about use it during your build phase, that's all right, but when the power trick? inmediatly during combat phase? All my problem came from reading about quicksilver with fate artifacts attack and later transfer the artifacts to another character using tower's fate.
Any help would be brilliant to help me to understand this rule.
Thank you to everyone.

Well, the attack-and-transfer plan doesn't work within the same turn...

Backup powers are all activated powers that have a timing use restriction that makes them only usable in the build phase. Some have delayed triggered effects that set up events that fire off later (Samantha Parrington, Nova, Ghost Rider). Others create modifiers that take effect immediately upon resolution (Hellcat, Surveillance Pawn). Basically, just read the individual effect and realize that it's only usable in the build phase. You can attack with Quicksilver on 2 or 3, and then use the Tower to shift up the Artifacts on 3 or 4, respectively, to make the new character all Fated out. You cannot, however, use the Tower in the combat phase to let another character get the Artifacts for more cheating pump benefits.

So let see if i undestood the answer, you pay for example in turn 2 and the artefacts will transfer to another character in turn 3? in which phase the will move?

No. You are misunderstanding.
When you play the Backup ability (in this case, on Dr. Fate's Tower) the effect resolves immediately.

So what is really happening is:
Turn 2: Equip your 2-drop with the fate artifacts.
Turn 3: Recruit your 3-drop, activate Dr. Fate's Tower and move all the equipment to your 3-drop.
Turn 4: Recruit your 4-drop . . . . etc. . .

There's no 'delay' in the Backup effect, it happens immediately after you use it, once the effect resolves.