Low-Voltage Switchgear and Controlgear - Rockwell …

1 Low-Voltage Switchgear and ControlgearTechnical Document LVSAM-WP001A-EN-P - April 2009 0-2 Disclaimer The present document is designed to provide general technical information about the selection and application of Low-Voltage switching and control devices and does not claim to provide a comprehensive or conclusive presentation of the considered material. Errors or changes for example as a consequence of changed standards or technical progress cannot be excluded. This documentation has been worked out with utmost diligence. Nevertheless the authors and Rockwell Automation do not warrant the correctness of the contents and recommendations and cannot exclude typing errors.

2 Claims on the authors or Rockwell Automation based on this documentation cannot be accepted. Rockwell Automation reserves the right to make changes at any time and at its own discretion. Correspondingly, qualified professional advice should be obtained before making decisions and initiating activities that could have an effect on technical equipment. The authors thank the International Electrotechnical Commission (IEC) for permission to reproduce information from its International Standard: IEC 60947-1 (2007) / IEC 60947-4-1 Am2 (2005) / IEC 60947-2 (2006) / IEC 60269-1 (2006) / IEC 60947-8 (2006) / IEC 60947-5-1 (2003 ) / IEC 60038 (2002) / IEC 60079-14 (2007).

3 All such extracts are copyright of IEC, Geneva, Switzerland. All rights reserved. Further information on the IEC is available from IEC has no responsibility for the placement and context in which the extracts and contents are reproduced by the authors, nor is IEC in any way responsible for the other content or accuracy therein. Rockwell Automation would like to thank the authors of the present document and their assis-tants for their valuable contributions. Authors: Dr. Werner Breer, Paul Hug, Urs Hunziker, Rey Kaltenrieder, Heinz Unterweger, Dr.

4 Hans Weichert With the inclusion of other specialists Copyright 2009 by Rockwell Automation, Milwaukee, USA LVSAM-WP001A-EN-P - April 2009 0-3 General preliminary comments The present technical manual is intended as an aid in project design and the application of Low-Voltage Switchgear and Controlgear in Switchgear assemblies and machine control. The focus of the document is on electromechanical Switchgear , however electronic devices used in Low-Voltage engineering have also been included. They are in many cases an effective alternative to mechanical devices.

5 The discussions relate insofar relevant to the IEC standards, which correspond to the European CENELEC standards. Where standards are quoted, the respective IEC designations are listed. The numbering of the CENELEC standards (EN) largely corresponds to that of the IEC standards. National standards ( DIN/VDE or BS) in some cases have differing number-ing for historical reasons, but in terms of content are largely identical to the IEC and EN standards, apart from rare national deviations. In relation to the requirements of other standard zones, especially in North America, reference is made to specific publications.

6 The physical characteristics are generally applicable. For Switchgear combinations the standard IEC 60439-1 is referred to that is in effect at issuance of this document. It is expected that IEC 61439-1 will shortly replace IEC 60439-1. The state-ments in the present documentation for Switchgear assemblies also apply for IEC 61439-1. Statements made in this document concentrate on the underlying principles and facts and avoid insofar as this is possible stating technical data relating to specific products in order to avoid premature obsolescence of the information contained.

7 The applicable technical data about the products should be obtained from the latest valid product documentation as published in printed and electronic catalogs and electronic documentation like RALVET. LVSAM-WP001A-EN-P - April 2009 0-4 0 Table of contents 0 Table of 0-5 1 Load characteristics and utilization 1-1 Utilization categories simplify the selection of 1-1 Electrical heating devices .. 1-4 Lamps and illumination 1-4 Incandescent 1-4 Halogen lamps .. 1-4 Discharge 1-4 1-5 Reactive power compensation and switching of 1-6 Reactive power 1-6 Individual 1-6 Group 1-7 Central 1-7 Switching of 1-7 Switching-on single 1-8 Switching of long, screened 1-8 Switching capacitors of central compensation 1-8 Control circuits, semiconductor load and electromagnetic 1-9 Three-phase asynchronous 1-9 Principle of 1-9 Slip-ring 1-11 Squirrel-cage induction 1-12 High efficiency motors.

8 1-14 Influence of the voltage across the 1-15 Performance of squirrel-cage induction motors with changing 1-16 2 Switching tasks and selecting the appropriate 2-1 Electrical equipment complying with standards and matching the application 2-1 Basic switching tasks and criteria for device 2-1 Device 2-2 Disconnectors (isolating switches).. 2-2 Load 2-3 Switch 2-3 Circuit 2-3 Supply disconnecting 2-3 Supply disconnecting EMERGENCY STOP 2-4 Summary supply disconnect and EMERGENCY STOP 2-5 2-5 Devices for thermal 2-5 Contactors.

9 2-5 Parameters for the correct selection and 2-5 Rated isolation voltage 2-7 Rated operational voltage Ue, rated operational current Ie and utilization category2-7 Rated impulse withstand voltage 2-7 Short-circuit withstand capacity and short-circuit 2-9 Joule integral I2t .. 2-10 Cut-off current 2-10 Rated short-time withstand current 2-10 LVSAM-WP001A-EN-P - April 2009 0-5 Current limiting protective 2-11 Coordination of electrical equipment .. 2-12 Coordination in respect of the switching capacity of the contactor (overcurrent selectivity).

10 2-12 Coordination with respect to the operability after a short-circuit .. 2-13 Short-circuit switching 2-14 Rated short-circuit making capacity 2-14 Rated short-circuit breaking capacity Icu and 2-14 Thermal 2-15 Ambient 2-15 Operational overcurrents, heavy-duty starting .. 2-15 Life 2-16 Prospective service 2-17 Mechanical life 2-17 Electrical life 2-17 Intermittent and short-time duty, permissible frequency of operation .. 2-20 Intermittent duty and relative 2-22 Rated frequency and 2-24 Safety 2-24 Mounting 2-25 Protective 2-25 Site 2-26 Shock and 2-26 Specific application conditions and switching 2-27 Parallel and series connection of 2-27 2-27 Series 2-27 AC Switchgear in DC 2-28 Applications at supply frequencies < 50 Hz and > 60 Hz.