Transformers can increase a turret's fire rate or reload speed within its radius. They cannot be placed right next to each other in a radius, but there is a bug that allows it. One turret in range of more than one transformer will only receive the bonus from the transformer with the most energy.
The bonuses will split and round down between all turrets in range, even if some are already fully powered.
When the power plant is destroyed, all Transformers will take damage equal to 90% of their current HP if they are still standing. If they are destroyed, the turret will lose it's boost.