交流電
The alternating current electric induction motor was independently introduced in 1888 by Galileo Ferraris and Nikola Tesla, by 1895 was beginning to allow electrical power to replace steam as a power source. The induction motor allowed alternating current to be used directly without any conversions. The first heavy AC motor users were various factories which typically replaced their steam power plants. Alternating current electrical power and its easy conversion with transformers from low to high voltage and back to low voltage made possible the widespread electrical grids we routinely use today for a myriad of tasks.