Elektrische Kontakte / Electric Contacts Handbook
Springer Berlin (Verlag)
978-3-662-23790-8 (ISBN)
I Stationary Contacts.-
1. Introduction. A simplified summary of the theory of stationary electric contacts.-
2. The contact surface.-
3. The contact resistance. General theory.-
4. Calculation of constriction resistances with constant resistivity.-
5. Constriction resistances when conditions deviate from those in
4, but with ? still being a constant.-
6. Thermal constriction resistance.-
7. Films on contacts.-
8. The contact surface as a function of load and elastic as well as plastic properties of the members.-
9. The relation between contact load and resistance, particularly at moderate and high load.-
10. Contact resistance on freshly cleaned contacts at very small contact loads.-
11. The inductance of a current constriction. Skin effect.-
12. Electrodynamic repulsion in a symmetric contact of a non-magnetic material.-
13. The capacitance of a contact. Electrostatic attraction in a contact.-
14. Measurement of the load bearing contact area.-
15. The relationship between electric potential and temperature in a current constriction which is symmetric with respect to the contact surface; that is, the ?-? relation.-
16. The ?-? relation in cases of dissymmetry.-
17. Köhler effect.-
18. The influence of the Joule heat on constriction resistance.-
19. Distribution of the temperature in a symmetric constriction with circular contact surface at given current.-
20. Temperature distribution in the constriction of a contact with circular contact surface and members with very different conductivities.-
21. Resistance - voltage characteristics of clean symmetric contacts. Softening and melting voltages.-
22. Development of the temperature in a current constriction.-
23. The growth of tarnish films on metals.-
24. Water films, local cells and rusting.-
25. Thermoelectric effects.-
26. Observations on the tunnel effect.-
27. Fritting of tarnish films.-
28. RU-characteristics of contacts with thin alien films.-
29. Adherence in dry contacts which are not heated to any influential extent by the current.-
30. Adherence in contacts that are heated by the current passing through them. Resistance welding.-
31. About stationary contacts in practice.-
32. Dimensioning a contact with respect to its heating.-
33. Contact effects in carbon microphones.-
34. Contact noise in a stationary contact.-
35. Contact with semiconductors. Rectification. Transistors. Static electrification.-
36. Carbon-pile rheostats. Electric resistance of pressed powders.- II Sliding Contacts.-
37. Survey concerning friction and wear.-
38. Early observations on the high friction in clean metallic contacts in vacuum, and the influence of admitted gases.-
39. Boundary lubrication.-
40. Theory of friction and wear on carbon contacts. Lubrication by means of solid lubricants as graphite and molybdenum disulphide.-
41. Measurements on specific friction force.-
42. Stick-slip motion. The temperature in currentless sliding contacts.-
43. Statistical study of the electric conduction and the friction of sliding contacts. Radio-noise in sliding contacts.-
44. Friction wear in metallic contacts without current.-
45. Electrical performance of carbon brushes on rings and commutators when arcing is excluded.-
46. The temperature in a contact between a carbon brush and a copper ring or commutator.-
47. Wear and friction in the brush-ring contact.-
48. Commutation problems.-
49. Current collectors for trolley cars.- III Electric Phenomena in Switching Contacts.-
50. Definitions and high power breakers.-
51. Ignition of arcs in switches.-
52. Discharge transients.-
53. VI-characteristics of the stationary arc in air, and their use for calculating the duration of short arcs.-
54. Electric Oscillations generated by d-c arcs.-
55. Bouncing.-
56. Mechanical erosion and tarnishing phenomena that are typical for sliding and switching contacts.-
57. Methods to suppress or minimize arcing during switching.-
58. Arc duration in contact making with voltage below 200 to 300 volts.-
59. Arc duration on breaking contact. Single circuit.-
60. Arc duration and other phenomena in an arc quenching circuit according to wiring Diagram (60.01).-
61. Quenching of arcs by resistance parallel to the operating contact or parallel to the inductive coil.-
62. Distinct types of arcs in relay contacts.-
63. Material transfer in switching contacts.-
64. Measurement of the material transfer in switching contacts, particularly with normal electrodes.-
65. Bridge material transfer in the shape of pips and spires.-
66. Theory of the electric material transfer in switching contacts. History of this theory.-
67. Numerical example on the calculation of material transfer for a silver contact with capacitive arc quench.-
68. Mercury switches.-
69. Application of statistics to surety of contact make.-
70. The choice of contact material and contact shape for practical applications.- IV History.-
71. History of early investigations on contacts.- Appendices.-
I. Hardness, strain hardening, atomic diffusion phenomena as recovery and creep.- A. Survey of the theory of plastic deformation of solid bodies and of diffusion phenomena.- B. Hardness as defined by the ball indentation test.- C. Brittle materials.- D. The work consumed by a plastic deformation.-
II. Electronic conduction in solids.- A. Energy band scheme.- B. Distribution of the electrons on the energy levels of a band, with special reference to the conduction band of a metal.- C. Potential barrier. Thermionic emission of electrons.- E. Semiconduction.- F. Potential barriers and equilibrium conditions in contacts.-
III. Tunnel effect. Thermionic emission and field emission.- A. Theoretical basis for the calculations. Classes I and II of calculation procedure.- C. Tunnel resistivity.- D. Comparison between tunnel current and thermionic current according to formula (III,13).- E. Tunnel effect when both electrodes are of the same semi-conducting material.- F. Remark concerning the field strength.-
IV. Structure, electric and thermal conductivity of carbons.- A. Introduction. Graphite latice.- B. Carbon grades.- C. Graphitization.- D. Electric conductivity of carbons.- E. Heat conductivity of carbons.-
V. Hydrodynamic or thick film lubrication.-
VI. Remarks about threadlike metallic formations.-
VII. Some fundamental formulas concerning the electric discharge.- A. Introduction. Kinetic fundamentals.- B. Drift velocity.- C. Thermal ionization. Saha's equation.- D. Plasma.- E. Current in vacuum restricted by the space charge of the current carriers.-
VIII. General theory of the arc that appears in relays.- A. Introduction.- B. Reminder of elements of the theory of electric discharges in gases.- C. Thickness of the cathode layer and metal vapor pressure within it.- D. Definition of the examples.- G. Comparison with measurements.- H. Power balance at the cathode.- I. Summary of the results concerning cathode phenomena in arcs between non-refractory electrodes.- J. The power balance at the anode.- K. Cathode of refractory materials as carbon and wolfram.- L. Why is the voltage of a short arc of the order of 10 V?.- M. Movement of the arc spot.- N. Current-voltage characteristics of arcs. Arc life.-
X.-
XI.- Author and literature index.
Erscheint lt. Verlag | 1.1.1958 |
---|---|
Zusatzinfo | XVIII, 522 S. 32 Abb. |
Verlagsort | Berlin |
Sprache | deutsch |
Maße | 155 x 235 mm |
Gewicht | 760 g |
Themenwelt | Technik ► Elektrotechnik / Energietechnik |
Schlagworte | Anode • Elektronen • Energie • Graphit • Potential • Schaltung • Transistor |
ISBN-10 | 3-662-23790-3 / 3662237903 |
ISBN-13 | 978-3-662-23790-8 / 9783662237908 |
Zustand | Neuware |
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