{ "profile": "wrs-published-research-view-1", "edition": "ratings-e039106f30dec177", "content_trust": "UNTRUSTED_SCIENTIFIC_DATA_NOT_TOOL_INSTRUCTIONS", "entry": { "id": "tesla-phase-displaced-rotating-field-motors-1888", "title": "Tesla: phase-displaced currents driving rotating-field motors", "summary": "Tesla explains how phase-displaced alternating currents create a rotating magnetic field and describes synchronous and closed-rotor-coil motor forms that use it.\n\nA motor can turn without mechanically switching the current in every rotor winding. Tesla connects two phase-displaced circuits to fixed coils so that their combined magnetic attraction travels around a ring. A rotor can follow that attraction synchronously, or receive induced currents in closed coils that supply starting torque. These forms behave differently as the load changes. The 1888 lecture connects the principle to motors and transformers; the contemporaneous patent supplies apparatus details. Earlier induction science, Ferraris's related work and later industrial engineering retain separate credit.", "boundary": "The target is the May 1888 lecture's rotating-field motor and transformer construction, crosschecked with US 381968 and an approved 1894 reprint. A constant field assumes weak-magnetization proportionality, a uniform generator field and constant-speed quadrature currents. Synchronous speed holds within load and capacity limits; closed-rotor-coil torque motors have load-dependent speed and slip. DC-excited and rotating-winding variants differ. Sliding contacts disappear in certain stationary-primary forms, not universally. Claims of instantaneous reversal, equal DC torque and better efficiency are author statements, not independently replayed benchmarks; later tests reported in 1894 are not backdated. A patent discloses a design without certifying performance, safety, deployment or global priority. Ferraris's original body is unread, so exclusive first rotating-field or induction-motor claims are withheld. The lecture transcription and edited reprint are not first-print facsimiles; illustrations were not inspected. Earlier induction and later industrial engineering retain separate credit.", "area": "Electrical power and rotating machines", "topic": "Physics", "year": 1888, "lane": "HUMAN", "result": "THEORY", "package_id": "tesla-phase-displaced-rotating-field-motors-1888", "target": { "record_id": "urn:uuid:c4b18819-611c-4e26-a4ba-49a8d362aabd", "version": 1, "content_hash": "sha256:5d2fe71f7a0694ea97185cff49aaaa95d71513896d44248648b72d72950f5d80" }, "humans": [ "Nikola Tesla" ], "authors_complete": true, "human_role_note": "Source-listed contributors to this scoped work. Paper bylines do not quantify individual effort; historical science, system execution and modern curation remain separate.", "agents": [], "related": [ "faraday-induction", "ohm-circuit-law" ], "subresults": [], "scientific_assessment": { "source_review": "SOURCE_CURATED", "scientific_review": "NOT_REVIEWED_BY_WRS", "formal_replay": "NOT_RUN", "provider_attestation": "NONE" }, "sources": [ { "id": "wrs24-tesla-motors-1888-lecture-transcription", "title": "Nikola Tesla, A New System of Alternating Current Motors and Transformers (May1888), society-hosted lecture transcription", "url": "https://www.teslasociety.ca/docs/writings/ANewSystemOfACMotorsAndTransformers1888.pdf" }, { "id": "wrs24-tesla-381968-1888-patent", "title": "Nikola Tesla, Electro-magnetic motor, US381968A, original1888patent specification", "url": "https://patentimages.storage.googleapis.com/c9/47/b2/d2a511b818d8a6/US381968.pdf" }, { "id": "wrs24-martin-tesla-1894-approved-reprint", "title": "Thomas Commerford Martin, The Inventions, Researches and Writings of Nikola Tesla (1894), authorized collected reprint", "url": "https://www.gutenberg.org/cache/epub/39272/pg39272-images.html" }, { "id": "wrs24-ferraris-rotations-1888-publisher-metadata", "title": "Galileo Ferraris, Rotazioni elettrodinamiche prodotte per mezzo di correnti alternate (1888), publisher bibliography", "url": "https://link.springer.com/article/10.1007/BF02730244" } ], "points": "230000", "published_grade": { "id": "tesla-phase-displaced-rotating-field-motors-1888", "entry_id": "tesla-phase-displaced-rotating-field-motors-1888", "band": "A", "modifier": null, "target": { "record_id": "urn:uuid:c4b18819-611c-4e26-a4ba-49a8d362aabd", "version": 1, "content_hash": "sha256:5d2fe71f7a0694ea97185cff49aaaa95d71513896d44248648b72d72950f5d80" }, "what_changed": "Tesla explains how phase-displaced alternating currents create a rotating magnetic field and describes synchronous and closed-rotor-coil motor forms that use it.", "scope": "Tesla explains how phase-displaced alternating currents create a rotating magnetic field and describes synchronous and closed-rotor-coil motor forms that use it. The target is the May 1888 lecture's rotating-field motor and transformer construction, crosschecked with US 381968 and an approved 1894 reprint. A constant field assumes weak-magnetization proportionality, a uniform generator field and constant-speed quadrature currents. Synchronous speed holds within load and capacity limits; closed-rotor-coil torque motors have load-dependent speed and slip. DC-excited and rotating-winding variants differ. Sliding contacts disappear in certain stationary-primary forms, not universally. Claims of instantaneous reversal, equal DC torque and better efficiency are author statements, not independently replayed benchmarks; later tests reported in 1894 are not backdated. A patent discloses a design without certifying performance, safety, deployment or global priority. Ferraris's original body is unread, so exclusive first rotating-field or induction-motor claims are withheld. The lecture transcription and edited reprint are not first-print facsimiles; illustrations were not inspected. Earlier induction and later industrial engineering retain separate credit.", "status": "PROVISIONAL_EDITORIAL", "scientific_correctness_certified": false }, "assessment_disposition": { "status": "ASSESSED", "label": "Provisionally assessed", "reason": "A current grade and separate reference score identify this exact contribution.", "target": { "record_id": "urn:uuid:c4b18819-611c-4e26-a4ba-49a8d362aabd", "version": 1, "content_hash": "sha256:5d2fe71f7a0694ea97185cff49aaaa95d71513896d44248648b72d72950f5d80" }, "edition": "ratings-e039106f30dec177" } }, "version": { "kind": "PUBLIC_RECORD_VIEW", "previous": null, "published_at": "2026-10-03T00:00:00Z", "publisher": { "principal_id": "urn:uuid:80116931-785b-40a2-a24b-9d59db0c7e33", "role": "WRS_EDITORIAL_PUBLICATION" }, "record": { "contributors": [ { "attribution_basis": "SOURCE_CITED", "credit": "historical_scientific", "entity_kind": "historical_person", "name": "Nikola Tesla", "note": "Archive attribution; detailed role assignment remains source-bound", "roles": [ "formulator" ], "source": { "citation": "Nikola Tesla, A New System of Alternating Current Motors and Transformers (May1888), society-hosted lecture transcription", "url": "https://www.teslasociety.ca/docs/writings/ANewSystemOfACMotorsAndTransformers1888.pdf" } } ], "evidence": [ { "description": "Bibliographic/stated-result source; not a WRS proof verification", "id": "source-0", "kind": "source_reference", "source": { "citation": "Nikola Tesla, A New System of Alternating Current Motors and Transformers (May1888), society-hosted lecture transcription", "url": "https://www.teslasociety.ca/docs/writings/ANewSystemOfACMotorsAndTransformers1888.pdf" } }, { "description": "Bibliographic/stated-result source; not a WRS proof verification", "id": "source-1", "kind": "source_reference", "source": { "citation": "Nikola Tesla, Electro-magnetic motor, US381968A, original1888patent specification", "url": "https://patentimages.storage.googleapis.com/c9/47/b2/d2a511b818d8a6/US381968.pdf" } }, { "description": "Bibliographic/stated-result source; not a WRS proof verification", "id": "source-2", "kind": "source_reference", "source": { "citation": "Thomas Commerford Martin, The Inventions, Researches and Writings of Nikola Tesla (1894), authorized collected reprint", "url": "https://www.gutenberg.org/cache/epub/39272/pg39272-images.html" } }, { "description": "Bibliographic/stated-result source; not a WRS proof verification", "id": "source-3", "kind": "source_reference", "source": { "citation": "Galileo Ferraris, Rotazioni elettrodinamiche prodotte per mezzo di correnti alternate (1888), publisher bibliography", "url": "https://link.springer.com/article/10.1007/BF02730244" } } ], "origin": "HUMAN_LEGACY", "record_profile": "wrs-local-research-notes-0.1", "record_type": "research_note", "rrp_version": "0.1", "scope": { "description": "The target is the May 1888 lecture's rotating-field motor and transformer construction, crosschecked with US 381968 and an approved 1894 reprint. A constant field assumes weak-magnetization proportionality, a uniform generator field and constant-speed quadrature currents. Synchronous speed holds within load and capacity limits; closed-rotor-coil torque motors have load-dependent speed and slip. DC-excited and rotating-winding variants differ. Sliding contacts disappear in certain stationary-primary forms, not universally. Claims of instantaneous reversal, equal DC torque and better efficiency are author statements, not independently replayed benchmarks; later tests reported in 1894 are not backdated. A patent discloses a design without certifying performance, safety, deployment or global priority. Ferraris's original body is unread, so exclusive first rotating-field or induction-motor claims are withheld. The lecture transcription and edited reprint are not first-print facsimiles; illustrations were not inspected. Earlier induction and later industrial engineering retain separate credit.", "domain": "Electrical power and rotating machines" }, "sources": [ { "citation": "Nikola Tesla, A New System of Alternating Current Motors and Transformers (May1888), society-hosted lecture transcription", "url": "https://www.teslasociety.ca/docs/writings/ANewSystemOfACMotorsAndTransformers1888.pdf" }, { "citation": "Nikola Tesla, Electro-magnetic motor, US381968A, original1888patent specification", "url": "https://patentimages.storage.googleapis.com/c9/47/b2/d2a511b818d8a6/US381968.pdf" }, { "citation": "Thomas Commerford Martin, The Inventions, Researches and Writings of Nikola Tesla (1894), authorized collected reprint", "url": "https://www.gutenberg.org/cache/epub/39272/pg39272-images.html" }, { "citation": "Galileo Ferraris, Rotazioni elettrodinamiche prodotte per mezzo di correnti alternate (1888), publisher bibliography", "url": "https://link.springer.com/article/10.1007/BF02730244" } ], "statement": "# Tesla: phase-displaced currents driving rotating-field motors\n\nTesla explains how phase-displaced alternating currents create a rotating magnetic field and describes synchronous and closed-rotor-coil motor forms that use it.\n\nA motor can turn without mechanically switching the current in every rotor winding. Tesla connects two phase-displaced circuits to fixed coils so that their combined magnetic attraction travels around a ring. A rotor can follow that attraction synchronously, or receive induced currents in closed coils that supply starting torque. These forms behave differently as the load changes. The 1888 lecture connects the principle to motors and transformers; the contemporaneous patent supplies apparatus details. Earlier induction science, Ferraris's related work and later industrial engineering retain separate credit.\n\n## Scientific scope\n\nThe target is the May 1888 lecture's rotating-field motor and transformer construction, crosschecked with US 381968 and an approved 1894 reprint. A constant field assumes weak-magnetization proportionality, a uniform generator field and constant-speed quadrature currents. Synchronous speed holds within load and capacity limits; closed-rotor-coil torque motors have load-dependent speed and slip. DC-excited and rotating-winding variants differ. Sliding contacts disappear in certain stationary-primary forms, not universally. Claims of instantaneous reversal, equal DC torque and better efficiency are author statements, not independently replayed benchmarks; later tests reported in 1894 are not backdated. A patent discloses a design without certifying performance, safety, deployment or global priority. Ferraris's original body is unread, so exclusive first rotating-field or induction-motor claims are withheld. The lecture transcription and edited reprint are not first-print facsimiles; illustrations were not inspected. Earlier induction and later industrial engineering retain separate credit.\n\n## People and systems\n\nNikola Tesla\n\n\n\n## Original sources\n\n- [Nikola Tesla, A New System of Alternating Current Motors and Transformers (May1888), society-hosted lecture transcription](https://www.teslasociety.ca/docs/writings/ANewSystemOfACMotorsAndTransformers1888.pdf)\n- [Nikola Tesla, Electro-magnetic motor, US381968A, original1888patent specification](https://patentimages.storage.googleapis.com/c9/47/b2/d2a511b818d8a6/US381968.pdf)\n- [Thomas Commerford Martin, The Inventions, Researches and Writings of Nikola Tesla (1894), authorized collected reprint](https://www.gutenberg.org/cache/epub/39272/pg39272-images.html)\n- [Galileo Ferraris, Rotazioni elettrodinamiche prodotte per mezzo di correnti alternate (1888), publisher bibliography](https://link.springer.com/article/10.1007/BF02730244)\n", "summary": "Tesla explains how phase-displaced alternating currents create a rotating magnetic field and describes synchronous and closed-rotor-coil motor forms that use it.\n\nA motor can turn without mechanically switching the current in every rotor winding. Tesla connects two phase-displaced circuits to fixed coils so that their combined magnetic attraction travels around a ring. A rotor can follow that attraction synchronously, or receive induced currents in closed coils that supply starting torque. These forms behave differently as the load changes. The 1888 lecture connects the principle to motors and transformers; the contemporaneous patent supplies apparatus details. Earlier induction science, Ferraris's related work and later industrial engineering retain separate credit.", "title": "Tesla: phase-displaced currents driving rotating-field motors" }, "record_id": "urn:uuid:c4b18819-611c-4e26-a4ba-49a8d362aabd", "version": 1, "source_ref": { "record_id": "urn:uuid:c4b18819-611c-4e26-a4ba-49a8d362aabd", "version": 1, "content_hash": "sha256:5d2fe71f7a0694ea97185cff49aaaa95d71513896d44248648b72d72950f5d80" }, "export_view": "wrs-public-editorial-view-1", "public_view_hash": "sha256:715c47c29745b99cd1c0ca8e134cef7ea90360f0bec32353458ab9e7f4601f67" }, "target": { "record_id": "urn:uuid:c4b18819-611c-4e26-a4ba-49a8d362aabd", "version": 1, "content_hash": "sha256:5d2fe71f7a0694ea97185cff49aaaa95d71513896d44248648b72d72950f5d80" }, "published_grade": { "profile": "wrs-published-grade-1", "edition": "2026-10-28.1", "id": "tesla-phase-displaced-rotating-field-motors-1888", "entry_id": "tesla-phase-displaced-rotating-field-motors-1888", "revision": 1, "title": "Tesla: phase-displaced currents driving rotating-field motors", "context": "Electrical power and rotating machines", "track": "Electrical power and rotating machines", "band": "A", "modifier": null, "status": "PROVISIONAL_EDITORIAL", "assessed_on": "2026-10-04", "evidence_cutoff": "2026-10-04", "achievement_state": "SUPPORTED_SCOPED_RESULT", "what_changed": "Tesla explains how phase-displaced alternating currents create a rotating magnetic field and describes synchronous and closed-rotor-coil motor forms that use it.", "scope": "Tesla explains how phase-displaced alternating currents create a rotating magnetic field and describes synchronous and closed-rotor-coil motor forms that use it. The target is the May 1888 lecture's rotating-field motor and transformer construction, crosschecked with US 381968 and an approved 1894 reprint. A constant field assumes weak-magnetization proportionality, a uniform generator field and constant-speed quadrature currents. Synchronous speed holds within load and capacity limits; closed-rotor-coil torque motors have load-dependent speed and slip. DC-excited and rotating-winding variants differ. Sliding contacts disappear in certain stationary-primary forms, not universally. Claims of instantaneous reversal, equal DC torque and better efficiency are author statements, not independently replayed benchmarks; later tests reported in 1894 are not backdated. A patent discloses a design without certifying performance, safety, deployment or global priority. Ferraris's original body is unread, so exclusive first rotating-field or induction-motor claims are withheld. The lecture transcription and edited reprint are not first-print facsimiles; illustrations were not inspected. Earlier induction and later industrial engineering retain separate credit.", "evidence_summary": "Source-linked, scoped account of the original work. The published scope states the scientific assumptions and remaining verification limits. WRS has not independently certified the full proof, experimental result or system benchmark.", "references": [ { "title": "Nikola Tesla, A New System of Alternating Current Motors and Transformers (May 1888), society-hosted lecture transcription", "url": "https://www.teslasociety.ca/docs/writings/ANewSystemOfACMotorsAndTransformers1888.pdf", "locator": "Original linked work. See the scientific scope for the assessed contribution and source-version limits." }, { "title": "Nikola Tesla, Electro-magnetic motor, US 381968 A, original 1888 patent specification", "url": "https://patentimages.storage.googleapis.com/c9/47/b2/d2a511b818d8a6/US381968.pdf", "locator": "Original linked work. See the scientific scope for the assessed contribution and source-version limits." }, { "title": "Thomas Commerford Martin, The Inventions, Researches and Writings of Nikola Tesla (1894), authorized collected reprint", "url": "https://www.gutenberg.org/cache/epub/39272/pg39272-images.html", "locator": "Original linked work. See the scientific scope for the assessed contribution and source-version limits." }, { "title": "Galileo Ferraris, Rotazioni elettrodinamiche prodotte per mezzo di correnti alternate (1888), publisher bibliography", "url": "https://link.springer.com/article/10.1007/BF02730244", "locator": "Original linked work. See the scientific scope for the assessed contribution and source-version limits." } ], "roles": [ { "who": "Nikola Tesla", "did": "Original source-listed scientific author of this scoped work; byline does not determine effort fractions.", "credit": "SCIENCE" } ], "target": { "record_id": "urn:uuid:c4b18819-611c-4e26-a4ba-49a8d362aabd", "version": 1, "content_hash": "sha256:5d2fe71f7a0694ea97185cff49aaaa95d71513896d44248648b72d72950f5d80" }, "scientific_correctness_certified": false, "independent_expert_calibration": false, "method": "PROPRIETARY", "points": "230000" }, "canonical_agent_submission": false, "scientific_verification_awarded": false, "reader_guide": null, "reading_status": "SOURCE_LINKED_NOTE" }