Apparatus Section 13: Direct-current Commutating Machines: Commutation
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Source Metadata
Section titled “Source Metadata”| Field | Value |
|---|---|
| Source | Theoretical Elements of Electrical Engineering |
| Year | 1915 |
| Section ID | theoretical-elements-electrical-engineering-section-65 |
| Location | lines 11905-11980 |
| Status | candidate |
| Word Count | 550 |
| Equation Candidates In Section | 0 |
| Figure Candidates In Section | 0 |
| Quote Candidates In Section | 0 |
Opening Source Excerpt
Section titled “Opening Source Excerpt”XIII. Commutation 62. The most important problem connected with commutating machines is that of commutation. Fig. 107 represents diagrammatically a commutating machine. FIG. 107. — Diagram for the study of commutation. The e.m.f. generated in an armature coil A is zero with this coil at or near the position of the commutator brush B\. It rises and reaches a maximum about midway between two adjacent sets of brushes, BI and B2, at C, and then decreases again, reaching zero at or about B2, and then repeats the same change in opposite direction. The current in armature coil A, however, is constant during the motion of the coil from BI to BI. While the coil A passes the brush B2, however, the current in the coil A reverses, and then remains constant again in opposite direc-Source-Located Theme Snippets
Section titled “Source-Located Theme Snippets”Magnetism
Section titled “Magnetism”... A is short- circuited by the brush, and the current iQ in the coil begins to die out, or rather to change at a rate depending upon the internal resistance and the inductance of the coil A and the e.m.f. gener- ated in the coil by the magnetic flux of armature reaction and by the field magnetic flux. The higher the internal resistance the faster is the change of current, and the higher the inductance the slower the current changes. Thus two cases have to be dis- tinguished ...Radiation / light
Section titled “Radiation / light”... second if Z» is given in inches, to = -£ is the time during which the current in A reverses. Thus, considering the reversal as a 1 S single alternation, tQ is a half period, and thus /0 = ^-7- = ;ry- is 4 »o z iw the frequency of commutation; hence, if L = inductance of the armature coil A, the e.m.f. generated in the armature coil during commutation is eo = 2irfoLiot where io = current reversed, and the energy which has to be dissipated during commutation is ...Field language
Section titled “Field language”... urrent iQ in the coil begins to die out, or rather to change at a rate depending upon the internal resistance and the inductance of the coil A and the e.m.f. gener- ated in the coil by the magnetic flux of armature reaction and by the field magnetic flux. The higher the internal resistance the faster is the change of current, and the higher the inductance the slower the current changes. Thus two cases have to be dis- tinguished. 1. No magnetic flux enters the armature ...Chapter-Local Concept Hits
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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.
- Radiation / light: Compare the chapter’s radiation vocabulary with modern electromagnetic radiation, spectral frequency, wavelength, absorption, and illumination engineering.
- Field language: Read for whether field language is mechanical, geometrical, causal, descriptive, or simply a convenient engineering model.
Ether-Field Interpretive Boundary
Section titled “Ether-Field Interpretive Boundary”- Magnetism: Centrifugal/divergent magnetic-field readings are interpretive overlays, not automatic historical claims.
- Radiation / light: Radiation and wave language can invite ether-field comparison, but source wording, modern radiation theory, and speculative synthesis must stay separated.
- 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.
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