NEMA BU 1.2-2002(R2008) Application Information for Busway Rated 600 Volts or Less.pdf
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1、 NEMA Standards Publication BU 1.2-2002 (R2008) Application Information for Busway Rated 600 Volts or Less Published by National Electrical Manufacturers Association 1300 North 17th Street, Suite 1752 Rosslyn, Virginia 22209 www.nema.org Copyright 2008 by the National Electrical Manufacturers Associ
2、ation. All rights including translation into other languages, reserved under the Universal Copyright Convention, the Berne Convention for the Protection of Literary and Artistic Works, and the International and Pan American Copyright Conventions. NOTICE AND DISCLAIMER The information in this publica
3、tion was considered technically sound by the consensus of persons engaged in the development and approval of the document at the time it was developed. Consensus does not necessarily mean that there is unanimous agreement among every person participating in the development of this document. The Nati
4、onal Electrical Manufacturers Association (NEMA) standards and guideline publications, of which the document contained herein is one, are developed through a voluntary consensus standards development process. This process brings together volunteers and/or seeks out the views of persons who have an i
5、nterest in the topic covered by this publication. While NEMA administers the process and establishes rules to promote fairness in the development of consensus, it does not write the document and it does not independently test, evaluate, or verify the accuracy or completeness of any information or th
6、e soundness of any judgments contained in its standards and guideline publications. NEMA disclaims liability for any personal injury, property, or other damages of any nature whatsoever, whether special, indirect, consequential, or compensatory, directly or indirectly resulting from the publication,
7、 use of, application, or reliance on this document. NEMA disclaims and makes no guaranty or warranty, expressed or implied, as to the accuracy or completeness of any information published herein, and disclaims and makes no warranty that the information in this document will fulfill any of your parti
8、cular purposes or needs. NEMA does not undertake to guarantee the performance of any individual manufacturer or sellers products or services by virtue of this standard or guide. In publishing and making this document available, NEMA is not undertaking to render professional or other services for or
9、on behalf of any person or entity, nor is NEMA undertaking to perform any duty owed by any person or entity to someone else. Anyone using this document should rely on his or her own independent judgment or, as appropriate, seek the advice of a competent professional in determining the exercise of re
10、asonable care in any given circumstances. Information and other standards on the topic covered by this publication may be available from other sources, which the user may wish to consult for additional views or information not covered by this publication. NEMA has no power, nor does it undertake to
11、police or enforce compliance with the contents of this document. NEMA does not certify, test, or inspect products, designs, or installations for safety or health purposes. Any certification or other statement of compliance with any health or safetyrelated information in this document shall not be at
12、tributable to NEMA and is solely the responsibility of the certifier or maker of the statement. BU 1.2-2002 (R2008) Page i CONTENTS Page Foreword ii Section 1 SCOPE1 Section 2 REFERENCED STANDARDS2 Section 3 RESISTANCE, REACTANCE, AND IMPEDANCE3 3.1Method to Determine Resistance, Reactance, and Impe
13、dance3 3.1.1Readings Taken During the Temperature-Rise Test3 3.1.2Calculate the Average Phase-to-Neutral Impedance Z3 3.1.3Calculate for Each Individual Phase .4 Section 4 VOLTAGE DROP6 4.1Voltage Drop Ratings 6 4.2Voltage Drop Test for Three-Phase BuswaysGeneral 6 4.3Calculation of Three-Phase Volt
14、age Drop and Voltage Drop Deviation .6 4.3.1Average Phase-to-Phase Voltage Drop6 4.3.2Phase-to-Phase Voltage Drop (VD) for Each Phase7 4.3.3The VDavg Calculated in Paragraph 4.3.2 .7 4.3.4The Percent Voltage Drop Deviation Per 100 Feet 7 4.4All Voltage Drops and Deviations Indicated in Section 4.3.7
15、 4.5The Voltage Drop of the Busway.7 4.6All Preceding Voltage Drop Formulas.8 Section 5 RESISTANCE WELDING APPLICATION9 5.1General9 5.2Current Carrying Requirements 9 5.2.1Group of Welders10 5.2.2Single-Phase Distribution Systems.10 5.2.3Three-Phase Distribution Systems .10 5.3Voltage Drop Requireme
16、nts10 5.3.1General11 5.3.2Determine Total During-weld kVA for Voltage Drop Calculations 11 5.3.3Determine Total During-weld Current for Voltage Drop Calculations.11 5.3.4Determine the Welder Multiplier for Voltage Drop Calculations .12 5.3.5Determine the Voltage Drop12 5.4Example Of Determining Prop
17、er Busway For Resistance Welder Application.12 5.4.1Example of Current Carrying Requirement Calculations12 5.4.2Example of Voltage Drop Requirement Calculations12 5.5Summary .13 Table 5-1 DUTY CYCLE MULTIPLIERS.9 Figure 3-1 METER CONNECTIONS 4 Copyright 2008 by the National Electrical Manufacturers
18、Association. BU 1.2-2002 (R2008) Page ii Foreword This Standards Publication is intended to provide a basis of common understanding within the electrical community. The purpose of this Standards Publication is to provide a guide of practical application information for busway rated 600 volts or less
19、. User needs have been considered throughout the development of this publication. Proposed or recommended revisions should be submitted to: Vice President, Engineering Department National Electrical Manufacturers Association 1300 North 17th Street, Suite 1752 Rosslyn, Virginia 22209 This Standards P
20、ublication was developed by the LVDE 04 Busway Product Group of the LVDE Section. Approval of the publication does not necessarily imply that all members voted for its approval or participated in its development. At the time it was approved, the Group/Section was composed of the following members: G
21、E Industrial SystemsPlainville, CT Siemens Energy thus reasonable assumptions should be made for these varying quantities and then used for the following determinations. To determine the busway current carrying capacity required, it is necessary to convert the intermittent welder loads to an equival
22、ent continuous load or effective kVA. If the during-weld kVA demand and the duty cycle for a welder are known, the effective kVA can be obtained by multiplying the during-weld kVA demand by the square root of the duty cycle divided by 10. The duty cycle is the percentage of the time during which the
23、 welder is loaded. For simplicity sake, multipliers for various duty cycles are listed in Table 5.1. Based upon the welders duty cycle, the proper multiplier is chosen. This multiplier times the during-weld kVA demand determines the effective kVA. Table 5-1 DUTY CYCLE MULTIPLIERS Percent Duty Cycle
24、Multiplier 50 0.71 40 0.63 30 0.55 25 0.50 20 0.45 15 0.39 10 0.32 7.5 0.27 5 or less 0.22 Copyright 2008 by the National Electrical Manufacturers Association. BU 1.2-2002 (R2008) Page 10 If the during-weld kVA demand is unknown, it can be assumed to be 70 percent of the welder secondary short-circu
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