A circuit breaker is an electrical safety device that protects a circuit from damage caused by excess current, interrupting the flow of electricity to prevent overheating and fire, and unlike a fuse it can be reset rather than replaced after it trips. Thomas Edison described an early form of the device in an 1879 patent application, though his commercial power systems used fuses instead, and the German engineer Hugo Stotz developed the modern automatic circuit breaker, patented in Germany as patent 458392 and brought to market by Brown, Boveri & Cie in 1924. Circuit breakers are now made in ratings from small household devices protecting individual appliances up to heavy switchgear protecting the high-voltage circuits that feed an entire city.
Facts
Patent or First-Use DateOnly the year 1879 is given for Edison's patent application in the cited source; no day or month is recorded. YearEdison's 1879 patent application described an early form; Brown, Boveri and Cie patented the modern miniature circuit breaker in 1924. SignificanceIts basic function is to interrupt current flow to protect equipment and to prevent fire. 1 FAQs
How does a circuit breaker know when to trip?
A heat-bent strip handles overloads and a magnetic coil handles short circuits.
A common thermal-magnetic circuit breaker uses two separate mechanisms. For a long overload, a strip inside it bends when it gets hot from too much current, and if the current stays high the strip bends more and trips the breaker. For a short circuit, a coil makes a strong magnetic field that pulls a plunger, which trips the breaker right away. Because the two mechanisms act on different faults, slow overloads and sudden short circuits are each handled in their own way.
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In Field
Source Circuit Breaker (Wikipedia)Wikipedia contributors
Sources
1. Circuit Breaker (Wikipedia)
Wikipedia contributors, Wikimedia FoundationOrigins section, opening sentence
An early form of circuit breaker was described by Thomas Edison in an 1879 patent application
Origins section, patent-date sentence
An early form of circuit breaker was described by Thomas Edison in an 1879 patent application
Operation section
Its basic function is to interrupt current flow to protect equipment and to prevent fire.
In Field: Electrical Engineering, Categories
Electric power systems components
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