Chapter 18: Surging Of Synchronous Motors
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Source Metadata
Section titled “Source Metadata”| Field | Value |
|---|---|
| Source | Theory and Calculation of Electric Apparatus |
| Year | 1917 |
| Section ID | theory-calculation-electric-apparatus-chapter-16 |
| Location | lines 20975-21712 |
| Status | candidate |
| Word Count | 2889 |
| Equation Candidates In Section | 0 |
| Figure Candidates In Section | 0 |
| Quote Candidates In Section | 0 |
Opening Source Excerpt
Section titled “Opening Source Excerpt”CHAPTER XVIII SURGING OF SYNCHRONOUS MOTORS 166. In the theory of the synchronous motor the assumption is made that the mechanical output of the motor equals the power developed by it. This is the case only if the motor runs at constant speed. If, however, it accelerates, the power input is greater; if it decelerates, less than the power output, by the power stored in and returned by the momentum. Obviously, the motor can neither constantly accelerate nor decelerate, without breaking out of synchronism. If, for instance, at a certain moment the power prod wed by the motor exceeds the mechanical load (as in the moment of throwing off a part of the load), the excess power is consumed by the momentum as acceleration, causing an increase of speed. The result thereof is that theSource-Located Theme Snippets
Section titled “Source-Located Theme Snippets”Transients / damping
Section titled “Transients / damping”... is manner a periodic variation of the phase relation between e and to, and correspond- ing variation of speed and current occurs, of an amplitude and period depending upon the circuit conditions and the mechanical momentum. If the amplitude of this pulsation has a positive decrement, that is, is decreasing, the motor assumes after a while a constant position of e regarding ea, that is, its speed becomes uniform. If, however, the decrement of Hie pulsation is negative, an infinitely small pulsation will continuously increase in amplitude, until the moto ...Field language
Section titled “Field language”... onditions of oscillation, and a period, which for small oscillations gives the frequency of oscillation: f „f _ //ee0 sin (a - 0) As instance, let: <?o = 2200 volts. Z = 1 + 4 j ohms, or, z = 4.12; a = 76°. And let the machine, a 16-polar, 60-cycle, 400-kw., revolving- field, synchronous motor, have the radius of gyration of 20 in., a weight of the revolving part of 6000 lb. The momentum then is Af„ = 850,000 joules. Deriving the angles, 0, corresponding to given values of output. P, and excitation, r, from the polar diagram, or from the symbo ...Radiation / light
Section titled “Radiation / light”... ulsation of the synchronous motor occurs, resulting in a change of the phase relation, 0, between the counter e.m.f., e, and the impressed e.m.f., e0 (the latter being of constant fre- quency, thus constant phase), by an angle, 5, where 8 is a periodic function of time, of a frequency very low compared with the impressed frequency, then the phase angle of the counter e.rn.f., e, is P + 6; and the counter e.m.f. is: E = e {cos (0 + 6) - j sin (p + 6)1, 19 290 ELECTRICAL APPARATUS hence the current: / = - {[e0 cos a — e cos (a + 0 + 5)] z — j [ ...Magnetism
Section titled “Magnetism”... scilla- tion of slip, in solid field poles, etc., a torque is produced more or less proportional to the deviation of speed from synchronism. This power assumes the form, Pi = c2s, where c is a function of the conductivity of the eddy-current circuit and the intensity of the magnetic field of the machine, c2 is the power which would be required to drive the magnetic field of the motor through the circuits of the anti-surging device at full frequency, if the same relative proportions could be retained at full fre- quency as at the frequency of slip, s. Th ...Chapter-Local Concept Hits
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| Frequency | 14 | seeded |
| Light | 1 | seeded |
Chapter-Local Glossary Hits
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Modern Engineering Reading Prompts
Section titled “Modern Engineering Reading Prompts”- Transients / damping: Separate the temporary term from the final steady-state term and compare with differential-equation response language.
- Field language: Read for whether field language is mechanical, geometrical, causal, descriptive, or simply a convenient engineering model.
- Radiation / light: Compare the chapter’s radiation vocabulary with modern electromagnetic radiation, spectral frequency, wavelength, absorption, and illumination engineering.
- Magnetism: Track flux, reluctance, permeability, magnetizing force, and loss language against modern magnetic-circuit terminology.
- Complex quantities: Track how Steinmetz preserves geometric rotation and quadrature while translating the same operation into symbolic form.
Ether-Field Interpretive Boundary
Section titled “Ether-Field Interpretive Boundary”- Transients / damping: Transient collapse, impulse, and surge behavior can be compared with alternative field language, but only as a clearly marked reading.
- 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.
- Magnetism: Centrifugal/divergent magnetic-field readings are interpretive overlays, not automatic historical claims.
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.