In 1916, engineer Henry E. Warren invented the master station clock, revolutionizing power transmission by regulating electricity frequency. Until the late 1940s, Warren’s clocks controlled over 95% of US electricity lines. The frequency standard of 60 hertz was established globally. Warren had a grand vision for electric clocks in every household, aiming to increase power consumption and revenue for power companies. Different versions of the master station clock were developed for various applications. Eventually, electronic clocks replaced Warren’s electromechanical clocks. General Electric acquired Warren’s company and continued his work. Today, Electric Time Co. in Mass. preserves the legacy of Warren’s clocks.
https://spectrum.ieee.org/history-of-power-grid