Chapter 11: Foucault Or Eddy Currents
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Source Metadata
Section titled “Source Metadata”| Field | Value |
|---|---|
| Source | Theory and Calculation of Alternating Current Phenomena |
| Year | 1900 |
| Section ID | theory-calculation-alternating-current-phenomena-1900-chapter-11 |
| Location | lines 8384-9380 |
| Status | candidate |
| Word Count | 5081 |
| Equation Candidates In Section | 0 |
| Figure Candidates In Section | 2 |
| Quote Candidates In Section | 0 |
Opening Source Excerpt
Section titled “Opening Source Excerpt”CHAPTER XI. FOUCAULT OR EDDY CURRENTS. 86. While magnetic hysteresis or molecular friction is a magnetic phenomenon, eddy currents are rather an elec- trical phenomenon. When iron passes through a magnetic field, a loss of energy is caused by hysteresis, which loss, however, does not react magnetically upon the field. When cutting an electric conductor, the magnetic field induces a current therein. The M.M.F. of this current reacts upon and affects the magnetic field, more or less ; consequently, an alternating magnetic field cannot penetrate deeply into a solid conductor, but a kind of screening effect is produced, which makes solid masses of iron unsuitable for alternating fields, and necessitates the use of laminated iron or iron wire as the carrier of magnetic flux. Eddy currents are true electric currents, though flowing in minute circuits;Source-Located Theme Snippets
Section titled “Source-Located Theme Snippets”Magnetism
Section titled “Magnetism”CHAPTER XI. FOUCAULT OR EDDY CURRENTS. 86. While magnetic hysteresis or molecular friction is a magnetic phenomenon, eddy currents are rather an elec- trical phenomenon. When iron passes through a magnetic field, a loss of energy is caused by hysteresis, which loss, however, does not react magnetically upon the field. When cutting ...Dielectricity / capacity
Section titled “Dielectricity / capacity”... ctive resistance of mutual inductance ; ^ = effective reactance of mutual inductance. The susceptance of mutual inductance is negative, or of opposite sign from the reactance of self-inductance. Or, Mutual inductance consumes energy and decreases the self- inductance. Dielectric and Electrostatic Phenomena. 98. While magnetic hysteresis and eddy currents can be considered as the energy component of inductance, con- densance has an energy component also, namely, dielectric hysteresis. In an alternating magnetic field, energy is con- sumed in hystere ...Field language
Section titled “Field language”CHAPTER XI. FOUCAULT OR EDDY CURRENTS. 86. While magnetic hysteresis or molecular friction is a magnetic phenomenon, eddy currents are rather an elec- trical phenomenon. When iron passes through a magnetic field, a loss of energy is caused by hysteresis, which loss, however, does not react magnetically upon the field. When cutting an electric conductor, the magnetic field induces a current therein. The M.M.F. of this current reacts upon and affects the magnetic field, more or less ; ...Impedance / reactance
Section titled “Impedance / reactance”... is proportional to the induced E.M.F., E, in the equation it follows that, TJie loss of power by eddy currents is propor- tional to the square of the E.M.F., and proportional to tlie electric conductivity of the iron ; or, W=aE*y. Hence, that component of the effective conductance which is due to eddy currents, is that is, The equivalent conductance due to eddy currents in the iron is a constant of the magnetic circuit ; it is indepen- dent of ^M..^., frequency, etc., but proportional to the electric conductivity of the iron, y. 87. Eddy currents ...Chapter-Local Concept Hits
Section titled “Chapter-Local Concept Hits”| Concept Candidate | Hits In Section | Status |
|---|---|---|
| Frequency | 27 | seeded |
| Ether | 4 | seeded |
| Light | 1 | seeded |
| Magnetic permeability | 1 | seeded |
Chapter-Local Glossary Hits
Section titled “Chapter-Local Glossary Hits”| Term Candidate | Hits In Section | Status |
|---|---|---|
| ether | 4 | seeded |
Equation Candidates
Section titled “Equation Candidates”| Candidate ID | OCR / PDF-Text Candidate | Source Location |
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| No chapter-local candidates yet | - | - |
Figure Candidates
Section titled “Figure Candidates”| Candidate ID | OCR / PDF-Text Candidate | Source Location |
|---|---|---|
theory-calculation-alternating-current-phenomena-1900-fig-081 | as shown in Fig. 81. Fig. 81. 92. Demagnetizing, or screening effect of eddy currents. | line 8748 |
theory-calculation-alternating-current-phenomena-1900-fig-082 | where / = total current in conductor. Fig. 82. The magnetic reluctance of a tubular zone of unit length | line 8940 |
Hidden-Gem Quote Candidates
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Modern Engineering Reading Prompts
Section titled “Modern Engineering Reading Prompts”- Magnetism: Track flux, reluctance, permeability, magnetizing force, and loss language against modern magnetic-circuit terminology.
- Dielectricity / capacity: Check whether the passage treats capacity, condensers, displacement, or dielectric stress as field storage rather than only circuit algebra.
- Field language: Read for whether field language is mechanical, geometrical, causal, descriptive, or simply a convenient engineering model.
- Impedance / reactance: Translate historical opposition terms into modern impedance, admittance, conductance, susceptance, and complex-plane notation.
- Radiation / light: Compare the chapter’s radiation vocabulary with modern electromagnetic radiation, spectral frequency, wavelength, absorption, and illumination engineering.
Ether-Field Interpretive Boundary
Section titled “Ether-Field Interpretive Boundary”- Magnetism: Centrifugal/divergent magnetic-field readings are interpretive overlays, not automatic historical claims.
- Dielectricity / capacity: A Wheeler-style reading may emphasize dielectric compression, field stress, and stored potential, but this page treats that as interpretation unless Steinmetz explicitly says it.
- Field language: Field-pressure or field-gradient interpretations can be explored here only after the explicit source passage and modern engineering translation are kept distinct.
- Radiation / light: Radiation and wave language can invite ether-field comparison, but source wording, modern radiation theory, and speculative synthesis must stay separated.
Promotion Checklist
Section titled “Promotion Checklist”- Open the full source text and the scan or raw PDF.
- Verify the chapter boundary and surrounding context.
- Promote exact quotations only after checking the source image.
- Move mathematical candidates into canonical equation pages only after formula typography is corrected.
- Move diagram candidates into the diagram archive only after image extraction, crop verification, and manifest creation.
- Keep Steinmetz wording, modern translation, and ether-field interpretation in separate labeled layers.