Solidifying Power Electronics [Historical]

More than a century ago, in 1902, American Engineer Peter Cooper Hewitt (1861-1921) derived the mercury-arc rectifier, enclosed in a glass bulb, from his mercury-vapor lamp of the previous year. He devised its use for feeding dc motors from alternating currents. As the first rectifier for power uses (two years before John Ambrose Fleming's diode and four years before Lee de Forest's audion [1]), the mercury-arc rectifier marked the birth of power electronics. The device was used in 1905 in Schenectady, New York, for powering a dc line for incandescent lamps and, soon after, in rectifiers for battery chargers and electrochemical processes, including aluminum reduction and electroplating. Aiming for higher powers, Cooper Hewitt introduced the metal casing with water cooling in 1909.