Powered Spawner

The Powered Spawner is a machine from Ender IO that spawns creatures when supplied power. It will spawn mobs as far as 4 blocks away.

After crafting the machine, it must be combined with a broken spawner on an anvil to set the type of mob it will spawn. Broken spawners can be acquired by breaking a Vanilla Minecraft spawner. Initially a broken spawner's type will be whatever it was when it was broken, but a broken spawner's type can be changed by combining it with a Soul Vial of the desired type in a Soul Binder. This allows the construction of spawners for creatures that do not have normal spawner blocks akin to Vanilla Minecraft's spawners.

The Powered Spawner is upgradeable with capacitors for increased power storage and spawn rate, at the cost for increased power usage.

More info

 * Powered Spawner on the Ender IO Wiki