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Commonly used terms in the Electrical industry.
core
(1) the operating image of a process (sometimes used to refer to the part residing in physical memory), often written to disk if the program crashes (dumping core). Since magnetized ferrite rings (cores) were once used in main memory to store a single bit each. The name remained and now core memory means the same as main memory,
although currently, main memory is chip-based. See also magnetic core memory.
(2) the ferromagnetic portion of a transformer or electric machine on which the coils are mounted. Typically made of laminated magnetic material, encircled by the windings, that provides a low reluctance path for magnetic flux.
(3) the central region of an optical fiber. The refractive index of the core must be higher than that of the cladding so that the optical power is guided through the fiber by total internal reflection at the core-cladding boundary. The core refractive index may be constant or may decrease with distance from the axis to the cladding. See also graded index and step index optical fiber.
(4) the section of a nuclear reactor in which the chain reaction is contained, comprising fuel rods, control rods, moderator, and coolant.
See
core lamination
core loss
loss in the ferromagnetic material comprising the core of an electric machine or transformer, composed of the sum of hysteresis losses and eddy current losses. These magnetic losses are caused by time varying fluxes in a ferromagnetic structure.
Hysteresis losses are caused by friction in molecules as the dipoles in a structure change direction of alignment in response to an applied alternating voltage, while eddy current losses are resistive losses .I 2R/, due to circulating currents in the core.
See
magnetic core memory
core-type transformer
a transformer in which the magnetic circuit upon which the windings are wound takes the form of a single ring. When the coils are placed on the core, they encircle the core.
See
core