The majority of IBM-implemented (actual) passive Token Ring MAUs operated without the requirement of power; instead the passive MAU used a series of relays that adjusted themselves as data is passed through: this is also why Token Ring generally used relays to terminate disconnected or failed ports.
[2] The advantages of having a MAU operate without power is that they can be placed in areas without outlets, the disadvantage is that they must be primed each time the internal relays experience excessive force.
The IBM 8226 MAU, while containing a power jack, primarily uses this for the LEDs: relays are still used inside the unit but do not require priming.
[3] In theory, this networking technology supported large geographic areas (with a total ring circumference of several kilometers).
But with the bandwidth shared by all stations, in practice separate networks spanning smaller areas were joined using bridges.