Pyromagnetic Electric Generator

Patented in 1890 under U.S. Patent 428,057, Tesla's pyromagnetic electric generator converted heat into electricity using temperature-induced magnetic property changes in iron cores. The device cycled ferromagnetic materials through heating (above Curie point to demagnetize) and cooling (to remagnetize), inducing currents in surrounding coils via flux variations. Tesla's prototype used flames or steam for heat, aiming at efficient thermal-to-electrical conversion without moving parts beyond fluid circulation. This early renewable concept targeted waste heat from factories or solar sources. It built on his electromagnetic expertise, predating modern thermoelectric generators.

Though not commercialized due to low efficiency and material constraints, it influenced thermomagnetic research for energy harvesting. Historical context places it amid Tesla's AC innovations, showcasing his interdisciplinary approach. Today, similar principles apply in magnetic refrigeration and waste heat recovery systems, promoting sustainability. Tesla's generator highlights his vision for harnessing ambient energy, inspiring green technologies.