The Repeater (or "Generator", depending on whether we will have it require an existing Reactor or not) is the little brother of the Reactor: While the latter provides power to the whole map and can only be built once, the Repeater is used whenever the human team wants to build many structures in one place. Just like the Reactor, it blows up in a huge fireball when destroyed.
Visually, we want it to pick up elements from the Reactor but be much smaller (less than ⅛ in volume). However, at the same time it should be significantly different from the similiarly sized Drill, which was also inspired by the Reactor design.
Here's a picture of the Reactor:
Here are some concepts originally made for the Reactor, but you can use them as inspiration for the Repeater:
The shape of the Repeater should be roughly like this (in fact this is a mockup made from a previous attempt) but more detail is encouraged:
Note that the animation should include some sort of arms rotating around the core.