William Stanley Jr.'s Early Alternating Current Transformer System
An 1886 patent describing an early design for an electrical transformer that helped make alternating current power distribution practical for homes and businesses.
Original patent title: “Signoe to geoege westing house”
An 1886 patent describing an early design for an electrical transformer that helped make alternating current power distribution practical for homes and businesses. Granted to William Stanley, Jr. in 1886 with 12 forward citations.
Key facts
Coverage
What does this patent actually cover?
This patent details an induction coil system designed to step down high-voltage alternating current (AC) to a lower, safer voltage suitable for lighting and small motors. By using a closed-core transformer, the system allowed electricity to be transmitted efficiently over long distances at high voltages and then converted locally for end-user safety. It effectively solved the problem of power loss that plagued early direct current (DC) systems.
The gap
What does this patent NOT cover?
- Does not cover direct current (DC) power distribution systems.
- Does not cover modern solid-state power electronics or switching power supplies.
- Does not cover polyphase power systems or three-phase generators.
These exclusions are unique to PatentBrief — derived from the actual claim language, not patent-office boilerplate.
What made this novel
The use of a closed-core transformer design significantly reduced magnetic leakage, allowing for much higher efficiency than the open-core designs that preceded it.
The Patent Drawing
Schematic visualization of the patent's claim structure. Hand-drawn diagrams in progress for each landmark patent.
Where you've seen this
Real-world examples
The Great Barrington, Massachusetts AC lighting demonstration of 1886
Early Westinghouse electrical distribution networks
Why it matters
The bigger picture
This technology was the backbone of the War of Currents between Westinghouse and Edison. It proved that AC could be transmitted over long distances, which ultimately led to the modern electrical grid architecture used globally today.
Granted
September 21, 1886
Market context
Who's building on this
Companies in this space
Modern electrical infrastructure companies like ABB, Siemens, and General Electric continue to refine the fundamental principles of transformer design established in this era.
Market impact
This patent enabled the rapid adoption of AC power, effectively ending the dominance of localized DC grids and allowing for the electrification of entire cities from centralized power plants.
Claim 1 — Plain English
What this patent covers
This patent details an induction coil system designed to step down high-voltage alternating current (AC) to a lower, safer voltage suitable for lighting and small motors. By using a closed-core transformer, the system allowed electricity to be transmitted efficiently over long distances at high voltages and then converted locally for end-user safety. It effectively solved the problem of power loss that plagued early direct current (DC) systems.
The clever bit
The use of a closed-core transformer design significantly reduced magnetic leakage, allowing for much higher efficiency than the open-core designs that preceded it.
What it does not cover
- Does not cover direct current (DC) power distribution systems.
- Does not cover modern solid-state power electronics or switching power supplies.
- Does not cover polyphase power systems or three-phase generators.
PatentBrief Score
Impact Score
Early stage
Citation count
22/40
Moderately cited
Claim breadth
0/20
Narrow claimsclaimsThe numbered statements at the end of a patent that legally define what the inventor owns.Read more →
Recency
0/20
Older than 20 years
Assignee scale
0/20
Independent or smaller assigneeassigneeThe entity that owns the patent — usually the inventor's employer or a company.Read more →
PatentBrief Impact Score — based on citation count, claim breadth, recency, and assignee scale. Not a legal assessment.
Heuristic Value Estimate
What this patent might be worth
$7K – $22K
Midpoint $13K · expired or expiring · industry ×1.4
Heuristic only — blends forward/backward citation counts, claim scope, time remaining, litigation history, and CPC-derived industry baseline. Real valuations need a professional appraisal.
Concepts involved
Citations
Patent lineage
Cite this patent
(1886). William Stanley Jr.'s Early Alternating Current Transformer System (U.S. Patent No. 349,611). U.S. Patent and Trademark Office. https://patentbrief.org/patent/us/349611/transformer-stanley
Auto-generated from the patent record. Double-check author order and the issue date against the official USPTO document before submitting.
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Common Questions
Frequently Asked Questions
What does William Stanley Jr.'s Early Alternating Current Transformer System cover?
An 1886 patent describing an early design for an electrical transformer that helped make alternating current power distribution practical for homes and businesses.
Who owns patent US 349611?
William Stanley, Jr. owns this patent, granted in 1886.
When does this patent expire?
This patent has expired and is now in the public domain — anyone can use the invention freely.
What is patent US 349611 cited by?
This patent has been cited by 12 later patents that build on its ideas.
What problem does this patent solve?
This technology was the backbone of the War of Currents between Westinghouse and Edison. It proved that AC could be transmitted over long distances, which ultimately led to the modern electrical grid architecture used globally today.
What does this patent NOT cover?
Does not cover direct current (DC) power distribution systems.
Patent monitoring