Patent · 1889 · age 33

US Patent 401520: Method Of Operating Electro-Magnetic Motors

Kept from patents.google.com · 1 file · 73 KBCall number TES PT1889.03

Provenance

Source: patents.google.com
Retrieved: 1 October 2026
Source terms (summary): Google terms: automated access against robots.txt counts as abuse
Rights: Public domainPatent text by Tesla, who died in 1943.Basis: author death year 1943, under a life-plus-70-years rule, as of 2026; other rules, such as the United States publication-date rules, are not assessed.
Formats: HTML
Fingerprint: 13c1b8e9da3ea9d2056f128007da5ab211b283ad63acfa5b509fe0fa812c2476sha256 of the file (64 characters). Any change to the file changes this code.
Cite as: Nikola Tesla, US Patent 401520: Method Of Operating Electro-Magnetic Motors (1889). Long Keeping, call number TES PT1889.03. https://longkeeping.com/nikola-tesla/us-patent-401520-method-of-operating-electro-magnetic-motors/

Unchanged since collected At the last check, on 2 October 2026, all 903 originals, this work's file among them, matched the fingerprints recorded when they were collected. Each copy is re-checked by hand once a year; there is no automatic alert yet.

Notes on this copy

#2Machine-read text (OCR), not proofread, with no page images in the file to check it against.

Original

googlepatents_US401520A.html

Open reading copy 73 KB Exact filePublic domain

Reading copy: the saved page with its pictures left out. A picture appears in the reading copy only once the library has recorded its licence, the licence is on the library's pass list, and it has been checked for a likeness. See its pictures at the source (another site). Exact file: the page byte for byte; its pictures do not load here.

Files

First pass, not a clearance.

Links inside these saved pages were written for the site they were saved from; some lead nowhere here.

File	Format	Size	Source	sha256	Label
googlepatents_US401520A.html exact filemain	HTML	73 KB	patents.google.com	13c1b8e9da3ea9d2056f128007da5ab211b283ad63acfa5b509fe0fa812c2476	Public domainPatent text by Tesla, who died in 1943.Basis: author death year 1943, under a life-plus-70-years rule, as of 2026; other rules, such as the United States publication-date rules, are not assessed.