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Google Patents, 2026-10-08

Searched

  • https://patents.google.com/patent/US1230615A/en (fetched by script; PDF downloaded)
  • Chrome: inventor "Charles P Steinmetz", q = (oscillations OR arc OR lightning OR surge), priority before 1924-01-01: "About 31 results"; first page read (10 results). A second page (num=50) did not render; not reached.

Found

  1. US 1,230,615 "Protective device", C. P. Steinmetz, Schenectady, assignor to General Electric Co.; filed 19 June 1913 (serial 774,513), granted 19 June 1917. [web: https://patents.google.com/patent/US1230615A/en; PDF research/files/US1230615-Steinmetz-protective-device-1917.pdf] The object is a device "which is selective in its action and permits a free flow of high frequency currents coming from one direction, but reflects such currents coming from the opposite direction". It rests on surge resistance R = sqrt(L/C): a circuit closed through its surge resistance takes any disturbance "without reflection"; "The surge resistance is independent of frequency"; line conductors have "a few hundred ohms", transformers "usually several thousand ohms". Construction: a high inductance in series with the line conductor, shunted by a non-inductive resistance about equal to the transformer's surge resistance, so disturbances leave the transformer freely but line disturbances are reflected. Motive stated: disturbances from lightning and switching "are of an oscillatory character, usually of high frequency, and tend to build up within the system dangerous and destructive voltages"; a disturbance trapped in the transformer "would by reflection increase in voltage". Bears on: claims 3 and 4 (surge impedance, reflection at a junction of different surge impedance, transformers as the endangered element), and on the protection Discharges p.150 proposes (dissipating oscillating energy in a resistance). It is a patented application of his traveling-wave theory, filed the year before the 1914 Discharges edition.
  2. Other hits on page 1 (titles only, not opened): US 1201646 Protective device (priority 1916-04-21); US 1276589 Thermoregulator (1917); US 1200257 and US 1200258 Arc-lamp (1912, 1913); US 892768 Electric-arc lamp (1902); US 896698 Arc-lamp (1903); US 678058 Electric-arc lamp (1901); US 1658746 Lightning arrester (priority 1921-09-27); US 987924 Rectifying system for aluminum-cell lightning-arresters (1910). Leads: US 1201646 (1916 protective device, likely a second surge-protection scheme) and US 1658746 (1921 lightning arrester, possibly the oxide-film arrester of his 1918 AIEE paper). Not read.

No foreign family members were checked (not reached). Result: positive.