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Tesla is granted U.S. Patent 381,968 for an electro-magnetic motor

On 1 May 1888 the United States issued Patent 381,968 to Nikola Tesla for an electro-magnetic motor using a rotating magnetic field. In the causal graph this event strengthens Energy Security, a driver that strengthens Poverty headcount ratio at $3.00 a day (2021 PPP) (% of population) — a worsening welfare path.

Sources: [1][2]

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On 1 May 1888 the United States issued Patent 381,968 to Nikola Tesla for an electro-magnetic motor using a rotating magnetic field. Related patents issued the same day covered electrical transmission of power.

Patent 381,968 for an electro-magnetic motor (1888-05-01).

Context

Commutator motors sparked and wore. A self-starting AC motor without brushes is the system-relevant claim. Galileo Ferraris published rotating-field experiments in 1888 from earlier Turin work. Sharing priority of the physical idea is not a reason to drop Tesla’s U.S. instrument.

Nikola Tesla is not the sole author of every later object, law, or museum label that uses the name. Shared work with courts, excavators, printers, spouses, officials, and later states does not erase a documented role, and it does not make an ancient person the signer of a twentieth-century statute.

Why it matters

High confidence on the U.S. patent; medium on uniqueness against Ferraris.

Ferraris is not a rumour. Store the U.S. patent without erasing Turin.

Who was responsible

Contribution type and responsibility level for each recorded actor — not sole-author shorthand.

  • Nikola Tesla

    Person

    Direct responsibility

    responsibility level 0.7 · verified

    He is the named inventor on the 1888 federal patent. Ferraris’s Turin demonstrations are a parallel independent path.

What changed

Fact → Driver → Indicator. Relationship strength orders the paths; it is not the observed indicator movement.

    1. FactTesla is granted U.S. Patent 381,968 for an electro-magnetic motor
    2. strengthensDriverEnergy Security
    3. strengthensIndicators (4)Poverty headcount ratio at $3.00 a day (2021 PPP) (% of population)
    Mixed path

    impact weight 0.55 · Effect from 1 May 1888 · verified

    A brushless induction motor on polyphase current is a generation-and-drive component that made long-distance AC useful as mechanical power, not only as lamps.

    • Poverty headcount ratio at $3.00 a day (2021 PPP) (% of population)

      via Energy Security

      Worse

      Strengthens · Relationship strength 0.34 (weight 0.55 × strength 0.62)

      Observed

      10.4% · 10.2 above the normal line (2024)

      Worse than normal

      7 readings, 2018–2024: fell from 11.1% to 10.4%.

      Above normal = worse

    • Inability to keep home adequately warm

      via Energy Security

      Better

      Weakens · Relationship strength 0.33 (weight 0.55 × strength 0.6)

      Observed

      7.97% of population aged 16 years or over · 5.2 above the normal line (2025)

      Worse than normal

      8 readings, 2018–2025: rose from 7.77% of population aged 16 years or over to 7.97% of population aged 16 years or over.

      Above normal = worse

    • Access to electricity (share of world population)

      via Energy Security

      Better

      Strengthens · Relationship strength 0.28 (weight 0.55 × strength 0.5)

      Observed

      91.6% of population · 8.4 below the normal line (2023)

      Worse than normal

      4 readings, 2020–2023: rose from 90.4% of population to 91.6% of population.

      Above normal = better

    All indicators on this path (4)

    • Life expectancy at birth

      via Energy Security

      Worse

      Weakens · Relationship strength 0.26 (weight 0.55 × strength 0.48)

      Observed

      80 Years · 2.3 below the normal line (2023)

      Worse than normal

      6 readings, 2018–2023: rose from 79.5 Years to 80 Years.

      Above normal = better

Evidence

The sources behind this fact and its verification state.

Verified2 sources on file
  1. 1.U.S. Patent 381,968 — Electro Magnetic Motor (1888)United States Patent and Trademark Office / Google Patents · High credibility · verified
  2. 2.Engineering and Technology History Wiki — Nikola TeslaIEEE / ETHW · High credibility · verified
What the sources establish

The patent text is a federal instrument. IEEE/ETHW independently treats the 1888 motor patents as Tesla’s core industrial contribution.

Established: U.S. Patent 381,968 on 1 May 1888 to Tesla. Not established: that he uniquely invented the rotating field in all jurisdictions, or that household electrification was already complete.

Causal path

How this event connects to drivers and indicators in the graph.

  1. ActorNikola Tesla
  2. contributed toFactTesla is granted U.S. Patent 381,968 for an electro-magnetic motor
  3. strengthensDriverEnergy Security
  4. strengthensIndicatorPoverty headcount ratio at $3.00 a day (2021 PPP) (% of population)

Cite this page

Factrail. (2026). Tesla is granted U.S. Patent 381,968 for an electro-magnetic motor. Factrail. https://factrail.ai/facts/us-tesla-patent-381968-1888

https://factrail.ai/facts/us-tesla-patent-381968-1888

Accessed 16 October 2026.

By the Factrail desk · Method: how we source and score · Last reviewed

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