Elektrische Kontakte / Electric Contacts Handbook

Front Matter....Pages I-XVIII
Introduction. A simplified summary of the theory of stationary electric contacts....Pages 1-8
The contact surface....Pages 8-10
The contact resistance. General theory....Pages 10-12
Calculation of constriction resistances with constant resistivity ϱ....Pages 13-20
Constriction resistances when conditions deviate from those in § 4, but with ϱ still being a constant....Pages 20-25
Thermal constriction resistance....Pages 25-27
Films on electric contacts, particularly adhesion films....Pages 27-33
The contact surface as a function of load, elastic and plastic properties of the members....Pages 33-39
The relation between contact load and resistance, particularly at moderate and high load....Pages 39-48
Contact resistance on freshly cleaned contacts at very small contact loads....Pages 48-51
The inductance of a current constriction Skin effect....Pages 52-55
Electrodynamic repulsion in a symmetric contact of non-magnetic material....Pages 55-56
The capacitance of a contact Electrostatic attraction in a contact....Pages 56-59
Measurement of the load bearing contact area....Pages 59-65
The relationship between electric potential and temperature in a current constriction which is symmetric with respect to the contact surface; that is, the φ-ϑ relation....Pages 65-70
The φ-ϑ relation in cases of dissymmetry....Pages 70-75
Kohler effect....Pages 75-78
The influence of the Joule heat on constriction resistances....Pages 78-84
Distribution of the temperature in a symmetric constriction with circular contact surface at given current, I....Pages 85-86
Temperature distribution in the constriction of a contact with circular contact surface and members with very different conductivities....Pages 87-90
Resistance-voltage characteristics of clean symmetric contacts. Softening and melting voltages....Pages 90-95
Development of the temperature in a current constriction....Pages 95-105
The growth of tarnish films on metals....Pages 105-116
Water films, local cells and rusting....Pages 116-118
Thermoelectric effects....Pages 118-121
Observations on the tunnel effect....Pages 121-130
Fritting of tarnish films....Pages 130-146
RU-characteristics of contacts with thin alien films....Pages 146-149
Adherence in dry contacts which are not heated to any influential extent by the current....Pages 150-154
Adherence in contacts that are heated by the current passing through them. Resistance welding....Pages 154-158
About stationary contacts in practice....Pages 158-168
Dimensioning a contact with respect to its heating....Pages 169-172
Contact effects in carbon microphones....Pages 172-183
Contact noise in a stationary contact....Pages 183-187
Contact with semiconductors. Rectification. Transistors. Static electrification....Pages 188-196
Carbon-pile rheostats Electric resistance of pressed powders....Pages 196-198
Survey concerning friction and wear....Pages 199-210
Early observations on the high friction in clean metallic contacts in vacuum, and the influence of admitted gases....Pages 210-212
Boundary lubrication....Pages 212-224
Theory of friction and wear on carbon contacts. Lubrication by means of solid lubricants as graphite and molybdenum disulfide....Pages 224-231
Measurements on specific friction force....Pages 231-233
Stick-slip motion The temperature in currentless sliding contacts....Pages 234-237
Statistical study of the electric conduction and the friction of sliding contacts. Radio-noise in sliding contacts....Pages 237-242
Friction wear in metallic contacts without current....Pages 242-254
Electrical performance of carbon brushes on rings and commutators when arcing is excluded....Pages 254-265
The temperature in a contact between a carbon brush and a copper ring or commutator....Pages 265-269
Wear and friction in the brush-ring contact....Pages 269-276
Commutation problems....Pages 276-288
Current collectors for trolley cars....Pages 288-289
Definitions and high power breakers....Pages 290-293
Ignition of arcs in switches....Pages 293-302
Discharge transients....Pages 302-304
VI-characteristics of the stationary arc in air, and their use for calculation of the duration of short arcs....Pages 304-316
Electric oscillations generated by d-c arcs....Pages 316-318
Bouncing....Pages 318-321
Mechanical erosion and tarnishing phenomena that are typical for sliding and switching contacts....Pages 321-326
Methods to suppress or minimize arcing during switching....Pages 326-331
Arc duration in contact making with voltage below 200 to 300 V....Pages 331-337
Arc duration on breaking contact. Single circuit....Pages 338-342
Arc duration and other phenomena in an arc quenching circuit according to wiring Diagram (60.01)....Pages 342-352
Quenching of arcs by a resistance parallel to the operating contact or parallel to the inductive coil....Pages 352-354
Distinct types of arcs in relay contacts....Pages 354-357
Material transfer in switching contacts....Pages 358-363
Measurement of the material transfer in switching contacts, particularly with normal electrodes....Pages 363-375
Bridge material transfer in the shape of pips and spires....Pages 375-376
Theory of the electric material transfer in switching contacts. History of this theory....Pages 376-387
Numerical example on the calculation of material transfer for a silver contact with capacitive arc quench....Pages 387-388
Mercury switches....Pages 388-390
Application of statistics to surety of contact make....Pages 390-394
The choice of contact material and contact shape for practical applications....Pages 394-397
History of early investigations on contacts....Pages 398-406
Erratum to: Introduction. A simplified summary of the theory of stationary electric contacts....Pages 525-525
Erratum to: Constriction resistances when conditions deviate from those in § 4, but with ϱ still being a constant....Pages 525-525
Erratum to: Development of the temperature in a current constriction....Pages 525-525
Erratum to: Contact noise in a stationary contact....Pages 525-525
Erratum to: Boundary lubrication....Pages 525-525
Erratum to: Theory of friction and wear on carbon contacts. Lubrication by means of solid lubricants as graphite and molybdenum disulfide....Pages 525-525
Erratum to: Methods to suppress or minimize arcing during switching....Pages 525-525
Erratum to: Arc duration in contact making with voltage below 200 to 300 V....Pages 525-525
Erratum to: Distinct types of arcs in relay contacts....Pages 525-525
Erratum to: Measurement of the material transfer in switching contacts, particularly with normal electrodes....Pages 525-525
Erratum to: Theory of the electric material transfer in switching contacts. History of this theory....Pages 525-525
Erratum to: Application of statistics to surety of contact make....Pages 525-525
Erratum....Pages 525-525
Erratum to: Commutation problems....Pages 525-525
Erratum to: VI-characteristics of the stationary arc in air, and their use for calculation of the duration of short arcs....Pages 525-525
Erratum to: The growth of tarnish films on metals....Pages 525-525
Erratum to: Calculation of constriction resistances with constant resistivity ϱ....Pages 527-527
Erratum to: The relationship between electric potential and temperature in a current constriction which is symmetric with respect to the contact surface; that is, the φ-ϑ relation....Pages 527-527
Erratum to: The φ-ϑ relation in cases of dissymmetry....Pages 527-527
Erratum to: The influence of the Joule heat on constriction resistances....Pages 527-527
Erratum to: Thermoelectric effects....Pages 527-527
Erratum to: Measurements on specific friction force....Pages 527-527
Erratum to: Material transfer in switching contacts....Pages 527-527
Erratum to: Wear and friction in the brush-ring contact....Pages 527-527
Erratum to: Quenching of arcs by a resistance parallel to the operating contact or parallel to the inductive coil....Pages 527-527
Erratum to: Development of the temperature in a current constriction....Pages 527-527
Erratum to: Commutation problems....Pages 527-527
Erratum to: VI-characteristics of the stationary arc in air, and their use for calculation of the duration of short arcs....Pages 527-527
Erratum....Pages 527-527
Back Matter....Pages 407-522