Background and History
When Illyria began to become unstable, Wesley created the generator to remove her powers to stop her from exploding. While he initially claimed that it would kill her, he later admitted that this was a lie. This caused Illyria to slaughter Team Angel before her unstable powers allowed Angel to change time. When Illyria was close to exploding, Illyria reluctantly agreed to allow Wesley to use the device on her. Wesley drained a good deal of her power, leaving her significantly weakened but still very powerful.
After Illyria's and Gunn's victory its whereabouts are unknown, or even if it still exists or functions.
The generator created a pinhole to an infinite extra-dimensional space, which acted like a negatively-charged pocket universe. The artificial space could store immense amounts of radiant energy and demonic power, even that of an Old One.