Short answers, pulled from the story.
Hippolyte Pixii invented alternating current in 1832 while building an alternator based on principles discovered by Michael Faraday. His device produced a current that periodically reversed direction rather than flowing in a single line.
The ZBD transformer patent applications occurred in 1885 by engineers Károly Zipernowsky, Ottó Bláthy, and Miksa Déri at the Ganz Works company in Budapest. Their closed magnetic circuit design was 3.4 times more efficient than the open-core bipolar devices that had preceded it.
The Niagara Falls Adams Power Plant began operation in August 1895 to prove that alternating current could transmit power over long distances from hydroelectric sources. This facility followed the 1893 contract Westinghouse secured to build the alternating current system for the Chicago World Exposition.
At 60 Hz the skin depth of a copper conductor is approximately 8.57 mm. This physical phenomenon forces current to flow away from the center of a wire and toward its outer surface within a thickness of a few skin depths.
Austria, Germany, Norway, Sweden, and Switzerland use 16.7 Hz power for their rail systems today. This frequency persists in European rail infrastructure as a standard for electric power distribution in these nations.
The peak voltage for a 230 V AC mains supply is approximately 325 V. This value represents the maximum swing between positive and negative values in the root mean square voltage cycle.