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CONTENIDO<br/>1. Specifications for low-voltage devices and switchgear assemblies 15<br/>Nomenclature of the standards authorities 15<br/>Low-voltage switchgear and devices 17<br/>Summary of specifications and approvals 17<br/>Regulations and approvals in European countries 17<br/>Standards and approvals in the U.S.A., Canada and Australia 22<br/>Type-tested and partially type-tested switchgear assemblies (TTA and PTTA) 26<br/>Summary of specifications and standards 26<br/>Construction specifications 26<br/>Generic specifications 31<br/>Equipping specifications 31<br/>Erection specifications 32<br/>Relevant DIN standards for switchgear assemblies 33<br/>Protection of persons and material assets 33<br/>Protection against direct contact 33<br/>Protection against electrical shock to DIN VDE 0100 33<br/>Protection against electrical shock, positioning of operating elements in the vicinity of parts which are dangerous to touch 34<br/>Measures to be taken in the modification or extension of switchgear assemblies already in service "Safety separation" with low-voltage switchgear 34<br/>Protection against indirect contact 38<br/>Comments related to the protective measures specific to the network configuration 40<br/>Protection by total insulation 42<br/>Erection and connection of switch and distribution boards 53<br/>Clearances and creepage distances 54<br/>Equipping specifications and relevant standards 56<br/>Main switches 57<br/>Emergency-off apparatus 58<br/>Safety disconnecting switches for mechanical maintenance (service/repair switches) 58<br/>The electrical equipping of industrial machinery scheduled for export to countries outside Germany 60<br/>Colours for pushbuttons, illuminated pushbuttons and indicator lights 62<br/>IP degrees of protection against contact with live parts, ingress of foreign bodies and ingress of liquid 63<br/>IP degrees of protection to DIN and IEC 63<br/>Degrees of protection according to other national specifications 64<br/>Operating and ambient conditions 65<br/>Normal conditions 65<br/>Ambient temperature 65<br/>Altitude 65<br/>Environmental influences 66<br/>Parameters and pollution levels of the climate classes to IEC 721 and the Siemens standard SN 29070, part 1. 68<br/>Protection against corrosion, type of finish for technical products 68<br/>Decontaminability 69<br/>Climatic operating conditions for electronic equipment 70<br/>Abnormal conditions for transport, storage and operation 72<br/>Arduous operating conditions 72<br/>Influence of and radiation 72<br/>Stressing due to vibrations and impact 73<br/>Measures against the effects of induced vibration 73<br/>Resistance to termites 74<br/>Environmental acceptability 74<br/>Suppression of radio interference 74<br/>2. Network data and duty types 76<br/>Network data 76<br/>Nominal voltages and frequencies 76<br/>Short-circuit current 79<br/>Types of short-circuits 81<br/>Contribution to the short-circuit current by connected motors 83<br/>Effects of short-circuit currents 84<br/>Diagrams for determining resistance values and short-circuit currents, computer program "KUBS" for short-circuit calculations and product selection 85<br/>Influence of the transformers and conductors on the short-circuit current 96<br/>Duty types 98<br/>Continuous operation duty 98<br/>Short-time operation duty 98<br/>Intermittent periodic duty 99<br/>Operation at inconsistent loading 102<br/>3. Selection criteria for low-voltage switchgear in main circuits 104<br/>Network and operating conditions 104<br/>Rated voltage and rated frequency 104<br/>Rated short-circuit strength and rated switching capacity 104<br/>Rated currents 106<br/>Switching tasks and conditions 106<br/>Switching tasks 106<br/>Disconnection 106<br/>Off-load switching 107<br/>On-load switching 107<br/>Motor switching 107<br/>Power switching, switching of shortcircuits 107<br/>Switching of components in an electrical installation 110<br/>Starting of low-voltage motors 111<br/>Switching of high-voltage motors 114<br/>Switching of capacitors 114<br/>Switching of electric heating equipment 115<br/>Switching of lamps in lighting installations 115<br/>Switching of low-voltage transformers 117<br/>Switching frequency and service life 117<br/>Permissible switching frequency 117<br/>Mechanical service life 118<br/>Electrical service life 118<br/>Selection in terms of utilization categories 118<br/>Selection of contactors 118<br/>Selection of load switches, disconnectors, on-load disconnectors and combination fuse switch units 121<br/>Protection against overcurrent and excessive temperature rise 122<br/>General functions 122<br/>Protection against overload 122<br/>Protection against the elects of short-circuits 123<br/>Protection against excessive temperature rise 123<br/>Specifications 123<br/>Specifications for overload protection devices 123<br/>Service factors in terms of UL and CSA specifications 124<br/>Specifications for overcurrent protection devices 125<br/>Specifications for temperature dependent protection devices 125<br/>Protection devices 125<br/>Fuses 125<br/>Circuit-breakers 128<br/>Line-protection (miniature) circuit-breakers 130<br/>Overload relays 131<br/>Thermistor motor protection devices 138<br/>Instantaneous electromagnetic over-current relays 139<br/>Switchgear combinations 139<br/>Swichgear combinations with fuses 139<br/>Switchgear combinations without fuses 141<br/>Switchgear combinations with thermistor motor protection devices 143<br/>Protection properties of switchgear combinations 144<br/>Comparison between the protection properties of switchgear combinations 146<br/>Selection of circuit-breakers for power distribution systems with or without fuses 148<br/>Protection of plant components 150<br/>Protection of three-phase induction motors 150<br/>Protection of conductors and cables outside the switchgear combinations 159<br/>Protection of transformers 160<br/>Protection of capacitors 163<br/>Discriminative protection (selectivity) 163<br/>Discrimination in radial networks 164<br/>Use of discrimination tables 172<br/>Discrimination in meshed networks 174<br/>Protection against overvoltage 175<br/>Overvoltage transients associated with vacuum switchgear 175<br/>High voltage vacuum contactors, type 3TL6, for the switching of three-phase inductive motors with slip-rings or short-circuited rotors over 1kV up to 12kV 177<br/>Vacuum contactors, type 3TF6, for the switching of three-phase induction motors with slip-ring or short-circuited rotors up to 1000V 182<br/>Leakage-current and earth-fault protection 183<br/>Construction and method of operation 183<br/>Leakage-current circuit-breakers for a.c. and pulsing d.c. leakage currents 184<br/>Discriminative leakage-current circuit-breakers 184<br/>Product range of Siemens leakage-current circuit-breakers and tripping devices 184<br/>Application of low-voltage switchgear in main circuits 185<br/>Parallel and series connection of current path assemblies 185<br/>Application of four-pole switchgear 186<br/>Influence of network frequency and harmonic currents on the operation of switching devices 187<br/>Thermal load carrying capacity of the current path assemblies and conductors in dependence of the network frequency 187<br/>Switching capacity at network frequencies other than 50 Hz 188<br/>Contact service life 189<br/>Tripping response of releases and relays 189<br/>The effect of harmonic currents on the tripping response of overload releases and relays 191<br/>Electrical operating mechanisms for switchgear 191<br/>Use of a.c. switchgear in d.c. networks 192<br/>Load carrying capacity of the current path assemblies 192<br/>Contact service life 193<br/>Direct-current switching capacity 193<br/>Use of a.c. contactors in networks with square-wave voltages 194<br/>Switchgear for the switching of three-phase capacitors 195<br/>Switching of capacitors with circuit-breakers 195<br/>Switching of capacitors with contactors 195<br/>Switching on of single capacitors 195<br/>Switching of capacitor banks 195<br/>Switching of capacitors with lower power ratings 196<br/>Selection of 3TF and 3TB contactors in terms of contact service life and utilization category 197<br/>Selection of 3TF contactors for short-time and intermittent periodic duty 201<br/>Selection of contactors for threephase pole-changing induction motors 204<br/>Selection of 3TF and 3TK contactors as well as circuit-breakers for the switching of lamps 206<br/>Switching of three-phase transformers up to 1000 V with 3TF contactors 210<br/>Starting of three-phase induction motors with slip-ring rotors 210<br/>3P A3 Oil-cooled starters 211<br/>Starter and start-control switches 219<br/>Starting of three-phase induction motors with stator-resistance starters 219<br/>Direct-on-line starting of three-phase induction motors with type 3TW motor starters 223<br/>A.C. semiconductor motor controllers and starters, SIKOSTART 3RW22 223<br/>4. Selection criteria for low-voltage switchgear in auxiliary circuits 233<br/>Operating voltages in auxiliary circuits 233<br/>Contact reliability in the case of low-voltages 233<br/>Voltage instability in auxiliary circuits 233<br/>Operating conditions 234<br/>Utilization categories to DIN VDE and IEC 234<br/>Special considerations for the selection and the use of low-voltage switchgear in Canada and the USA 234<br/>Short-circuit protection in auxiliary circuits 236<br/>Short-circuit and overload protection of control transformers 237<br/>Thermistor protection in control transformers 237<br/>Operating conditions for low-voltage switchgear in auxiliary circuits 237<br/>Prevention of operational down-time in contactor control systems 237<br/>Long control conductors - problems and solutions 242<br/>Limiting of overvoltage spikes caused by the switching off of contactors (overvoltage supresión) 248<br/>Causes of overvoltages 248<br/>Overvoltage suppression with RC elements 249<br/>Overvoltage suppression with diodes 253<br/>Overvoltage suppression with varistors 253<br/>The use of contactor relays in safety circuits 254<br/>Selection criteria for low-voltage control transformers 257<br/>Operating conditions 257<br/>Duty types 259<br/>Transformer types 260<br/>Application and selection of position switch es, type 3SE 266<br/>Position switches with safety function 271<br/>5. Installation, operation and maintenance of low-voltage switchgear 273<br/>Installation 273<br/>Mounting aids 273<br/>Mounting position 274<br/>Clearance for switching-arc gases 275<br/>Termination 275<br/>SIGUT termination technique 275<br/>Tab connectors 276<br/>Box terminals 277<br/>Operation 277<br/>Manual operation 277<br/>Powered operation 279<br/>Measures to facilitate the checking replacement of parts and maintenance work 279<br/>Checking the condition of contact pieces in 3TF contactors; assessment criteria 280<br/>6. Transducing sensors and signal processing systems 282<br/>Selection criteria for BERO proximity switches 283<br/>Inductive and capacitive proximity switch es for operating distances up to 65 mm 283<br/>Opto-BERO photoelectric proximity switches 286<br/>Sonar-BERO ultrasonic proximity switches 287<br/>Electronically compatible control and signalling by low-voltage switchgear 291<br/>Reliable operation by electronic output stages 291<br/>Adaptation of the operating voltage tolerances 292<br/>Overvoltage suppression 292<br/>Contact reliability 293<br/>Assessment criteria for electromechanical and electronic controls 297<br/>7.Type-tested switchgear assemblies (TTA) 299<br/>General 299<br/>Versions and designs 299<br/>Types of construction 302<br/>Selection criteria 306<br/>Switchboards in standardized design 308<br/>Introduction 308<br/>Standard switchboards Type 8PU 313<br/>Transformer load centre (S) substations for up to 24 kV and 1250 kV A 320<br/>Distribution board systems 328<br/>8HS sheet-steel enclosed distribution boards 328<br/>8HU sheet-steel enclosures 329<br/>8HP insulated distribution board system 329<br/>8PL insulated busbar trunking system (L-system) 330<br/>8L. mounting and wiring systems for control circuits 331<br/>8MF cubicle system for switch, distribution and control boards 332<br/>Guidelines for project planning of low voltage switch, distribution and control boards or systems 333<br/>General 333<br/>8PU low-voltage switchboards 338<br/>8HS, 8HP and 8HU distribution systems 340<br/>8L. mounting systems for control circuits 340<br/>Domestic and utility distribution boards 340<br/>8GB Small distribution boards 343<br/>8GD and 8GA STAB wall-mounting/ SIKUS floor-standing distribution board systems 344<br/>8GA SIKUS free-standing distribution board cubicles 346<br/>SIPRO universal system meter cabinets, meter/distribution cubicles, distribution cabinets, free-standing distribution boards 348<br/>8MB, 8MM and 8GR cable, distribution and meter cubicles for outdoor use 350<br/>Air-conditioning of installations, switchboards and cubicles 351<br/>General 351 7.4.6.2 8ME78 heat exchangers 354<br/>8MR11 filtered fans 355<br/>8MR17 refrigeration units 356<br/>8MR21 heating units 357<br/>Temperature rise inside insulation material and sheet steel enclosures 358<br/>Degrees of protection, climatic and other ambient conditions 360<br/>Power factor correction in networks with or without harmonics 363<br/>Basic principles 363<br/>Types of power factor correction (re active power compensation) 365<br/>Power factor correction of three-phase induction motors and transformers 367<br/>Project planning 369<br/>Voltage rise caused by capacitors 372<br/>Compensation in networks with harmonics 373<br/>The use of audio-frequency remote control systems 377<br/>Range of products for power factor correction 380<br/>Charging units for stationary standby battery installations 382<br/>Current transformers 385<br/>Basic designs 385<br/>Current transformers for specific applications 386<br/>Interposing current transformers 386<br/>Summation current transformers 386<br/>Thread-through (ar pin-wound) current transformers 388<br/>Cable or busbar current transformers (split-core c.t.'s) 388<br/>Cast resin current transformers 388<br/>Explosion-protected current transformers and current transformers for mining applications 388<br/>Current transformers for protection purposes 389<br/>Current transformers for power factor correction controllers 389<br/>Accuracy classes of current transformers 390<br/>Secondary currents of current transformers 391<br/>Rated output power and overcurrent factor of current transformers 391<br/>Voltages across the secondary terminals of a current transformer 392<br/>Selection criteria for current transformers 394<br/>Power consumption and losses in current transformer secondary circuits 394<br/>8. Fundamental circuit diagrams 397<br/>General information 397<br/>Terminal designations 397<br/>Graphic symbols according to DIN, ANSI, BS and IEC 400<br/>Designation of equipment, conductors and general functions 408<br/>Circuit diagrams 410<br/>Types of circuit diagrams 410<br/>Making use of the fundamental circuit diagrams or modifying them 412<br/>Switching via contactors 412<br/>Contactors with drop-out delay unit for fluttering command signals 412<br/>Extended (early-make / late-break) auxiliary contacts in contactors (mainly for d.c. excitation of the coils) 414<br/>Drop-out delay units for contactors 414<br/>Contactor safety combinations 414<br/>Direct switching of three-phase induction motors 415<br/>Switching on and off of three-phase induction motors 415<br/>Switch-over of a three-phase induction motor from one supply network to another 416<br/>Automatic sequential starting of three-phase induction motors 418<br/>Reversing the direction of rotation of three-phase induction motors (reversing starters) 420<br/>Switching of pole-changing threephase induction motors 422<br/>Pole-changing three-phase induction motor with one winding (Dahlander connection), two speeds, one direction of rotation 422<br/>Pole-changing three-phase induction motor with one winding (Dahlander connection), two speeds, two directions of rotation 424<br/>Pole-changing three-phase induction motor with two separate windings, two speeds, one direction of rotation 426<br/>Pole-changing three-phase induction motor with two separate windings, two speeds, two directions of rotation 428<br/>Pole-changing three-phase induction motor with three speeds, one direction of rotation, one winding in a Dahlander connection, and one separate winding for low speed 430<br/>Pole-changing three-phase induction motor with three speeds, one direction of rotation, one winding in a Dahlander connection, one separate winding for the intermediate speed 432<br/>Pole-changing three-phase induction motor with three speeds, one direction of rotation, one winding in a Dahlander connection, one separate winding for high speed 434<br/>Pole-changing three-phase induction motor with three speeds, two directions of rotation, one winding in a Dahlander connection, one separate winding for low speed 436<br/>Pole-changing three-phase induction motor with four speeds, one direction of rotation and two separate windings 440<br/>Starting of three-phase induction motors 444<br/>Star-delta starting of three-phase induction motors with star contactor, delta contactor and line contactor 444<br/>Closed transition star-delta starting of three-phase induction motors 446<br/>Four stage star-delta starting 448<br/>Star-delta starting of three-phase induction motors in two directions of rotation 450<br/>Star-delta starting of three-phase induction motors with power factor correction 452<br/>Automatic starting of three-phase squirrel-cage motors via a single-pole stator-resistor (KUSA connection) using a time relay 454<br/>Automatic starting of three-phase induction motors via a three-pole stator-resistor using a time relay 456<br/>Automatic starting of three-phase slip-ring motors 458<br/>Closed transition autotransformer starting of three-phase' squirrel-cage motors (Korndéirfer connection) 460<br/>Circuits with thermistor motor protection 462<br/>Thermistor motor protection with positive temperature coefficient (PTC) temperature sensors 462<br/>Thermistor motor protection for a pole-changing three-phase induction motor with two separate windings and two speeds 462<br/>PTC thermistor motor protection for alarm and switch-off of a three-phase induction motor with six sensors via a circuit-breaker for motor protection equipped with overload and shortcircuit releases 464<br/>Thermistor motor protection for the switching off of six three-phase induction motors via contactors 466<br/>Thermistor motor protection with negative temperature coefficient (NTC) temperature sensors 468<br/>Circuits with monitors 470<br/>Circuits with speed monitors 470<br/>Direct-on-line starting of three-phase induction motors. Stopping by reverse-current braking (plug braking) 470<br/>Direct-on-line starting of three-phase induction motors. Stopping by reverse-current braking (plug braking).Circuit with contactor relay 472<br/>Direct reversal of three-phase induction motors with reverse-current or plug braking in both directions of rotation 474<br/>Circuits with conveyor belt monitors 476<br/>Circuits of contactor control systems with pressure monitors 478<br/>Circuits with position switches 479<br/>Reverser circuits with position switches (e.g. gate control) 479<br/>Position switches with indicator lights 480<br/>Terminal blocks 482<br/>Circuits with isolating terminal blocks for current transformers 482<br/>Circuit-breaker terminals for auxiliary circuits 484<br/>Circuits with leakage-current (residual-current) protective devices 486<br/>Contents<br/>Interface units 487<br/>Auxiliary circuits incorporating time relays 488<br/>Star-delta starting of three-phase induction motors with star contactor, delta contactar, line contactor and time relay 488<br/>Functions of the motor-driven time relay 7PR4140 490<br/>Switching of an electrical heating system using a thermostat and contactor combination 491<br/>Stand-by power supply installations 492<br/>Three-pole change-over fram network supply to stand-by supply using contactors (generator operation) 493<br/>Change-over fram network supply to stand-by supply with four-pole disconnection of the distribution system via two three-pole contactors 494<br/>Project planning and engineering aids 496<br/>9. Appendix 499<br/>Fundamental equations, characteristic quantities and units of electricity 499<br/>Fundamental equations of electrical engineering 499<br/>Characteristic quantities and units of electricity in accordance with DIN VDE and IEC 500<br/>Differences in the IEC 157-1 and IEC 947-2 publications 502<br/>Equation symbols and SI units International System of Units (SI) 503<br/>Conversion of international, British and American units 507<br/>Enclosures for electrical equipment to American and Canadian standards 512<br/>Clima tic values, influence of temperature and thermal conduction 514<br/>Climatic values 514<br/>Effects of temperature and thermal conduction 514<br/>Current carrying capacity and overcurrent protection of insulated wires, cables and busbars 516<br/>Coordination of protection devices 517<br/>Overload protection 517<br/>Short-circuit protection 518<br/>Current carrying capacity 521<br/>Load ratings of insulated conductors at ambient temperatures of 30° to 70°C and the assignment of cable protection fuses in accordance with USA and Canadian standards 525<br/>Thermal ratings of busbars and device terminals 527<br/>Resistance of copper and aluminium conductors 529<br/>Rated currents of three-phase induction motors 530<br/>Three-phase power transformers 532<br/>Graphic symbols and vector groups of three-phase power transformers 535<br/>Tripping behaviour of line protection and switchgear protection devices 536<br/>Time-current tripping characteristics of circuit-breakers, miniature circuitbreakers and overload relays 536<br/>Pre-arcing time-current characteristics of fuses (operating classes gL/gG and aM) 536<br/>Characteristic curves and tripping behaviour of circuit-breakers 539<br/>Current-limiting diagrams of fuses 541<br/>Discrimination (selectivity) between fuses and circuit-breakers 543<br/>Short-circuit currents 546<br/>Limiting effect of conductors and cables on short-circuit currents 546<br/>Dynamic forces created by shortcircuit currents 547<br/>Number of switehing operations of switehing devices subjeeted to different operating periods per day 548<br/>International network voltages and frequencies 549<br/>EC guidelines for low voltage equipment 555<br/>Glossary - Brief explanations of some teehnical terms 556<br/>Addresses of important specifieation, standards and testing bodies 643<br/>Index 645 |
