Skip to content

Apparatus Section 15: Synchronous Machines: Fluctuating Cross Currents in Parallel Operation

Research workbench, not a finished commentary page.

This page is generated from processed source text and candidate catalogs. It exists to help researchers decide what to verify, promote, and deeply decode next.

FieldValue
SourceTheoretical Elements of Electrical Engineering
Year1915
Section IDtheoretical-elements-electrical-engineering-section-36
Locationlines 9918-10123
Statuscandidate
Word Count1491
Equation Candidates In Section0
Figure Candidates In Section0
Quote Candidates In Section0
XV. Fluctuating Cross Currents in Parallel Operation 27. In alternators operated from independent prime movers, it is not sufficient that the average frequency corresponding to the average speed of the prime movers be the same, but still more important that the frequency be the same at any instant, that is, that the frequency (and thus the speed of the prime mover) be constant. In rotary prime movers, as turbines or electric motors, this is usually the case; but with reciprocating machines, as steam engines, the torque and thus the speed of rotation rises and falls periodically during each revolution, with the frequency of the engine impulses. The alternator con- nected with the engine will thus not have uniform frequency, but a frequency which pulsates, that is, rises and falls. The amplitude of this pulsation depends
XV. Fluctuating Cross Currents in Parallel Operation 27. In alternators operated from independent prime movers, it is not sufficient that the average frequency corresponding to the average speed of the prime movers be the same, but still more important that the frequency be the same at any instant, that is, that the frequency (and thus the speed of the prime mover) be constant. In rotary prime ...
... rs out of synchro- nism with each other, especially when the conditions are favorable to a cumulative increase of this effect by what may be called mechanical resonance (hunting) of the engine governors, etc. They depend upon the synchronous impedance of the alternators and upon their phase difference, that is, the number of poles and the fluctuation of speed, and are specially objectionable when operating synchronous apparatus in the system. 28. Thus, for instance, if two 80-pole altern ...
... the problem of parallel operation is made more difficult by the more jerky nature of the gas-engine ^ 73._Phase displacement between impulse. In such machines, alternators to be synchronized, therefore, squirrel-cage wind- ings in the field-pole faces are commonly used, to assist synchron- izing by the currents induced in this short-circuited winding, on the principle of the induction machine. From Fig. 73 it is seen that the e.m.f. OEr or EiE2, which causes the cross current ...
... of its mean posi- tion by 1/4 per cent, of 20 or 1/20 pole, that is, 180/20 = 9 elec- trical space degrees. If the armature of the other alternator at this moment is behind its average position by 9 electrical space degrees, the phase displacement between the alternator e.m.fs. is 18 electrical time degrees; that is, the alternator e.m.fs. are represented by OEi and OEZ in Fig. 71, and when running in parallel the e.m.f. OEf = E\E^ is short circuited through the synchronous impedanc ...
Concept CandidateHits In SectionStatus
Frequency12seeded
Term CandidateHits In SectionStatus
No chapter-local term hits yet--
Candidate IDOCR / PDF-Text CandidateSource Location
No chapter-local candidates yet--
Candidate IDOCR / PDF-Text CandidateSource Location
No chapter-local candidates yet--
Candidate IDCandidate PassageSource Location
No chapter-local candidates yet--
  • Radiation / light: Compare the chapter’s radiation vocabulary with modern electromagnetic radiation, spectral frequency, wavelength, absorption, and illumination engineering.
  • Impedance / reactance: Translate historical opposition terms into modern impedance, admittance, conductance, susceptance, and complex-plane notation.
  • Field language: Read for whether field language is mechanical, geometrical, causal, descriptive, or simply a convenient engineering model.
  • Dielectricity / capacity: Check whether the passage treats capacity, condensers, displacement, or dielectric stress as field storage rather than only circuit algebra.
  • Lightning / surges: Connect the passage to switching surges, traveling waves, reflections, insulation stress, and protection practice.
  • 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.
  • 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.
  1. Open the full source text and the scan or raw PDF.
  2. Verify the chapter boundary and surrounding context.
  3. Promote exact quotations only after checking the source image.
  4. Move mathematical candidates into canonical equation pages only after formula typography is corrected.
  5. Move diagram candidates into the diagram archive only after image extraction, crop verification, and manifest creation.
  6. Keep Steinmetz wording, modern translation, and ether-field interpretation in separate labeled layers.