1、NEMA Standards PublicationNational Electrical Manufacturers AssociationNEMA ICS 7.2-2015Application Guide for AC Adjustable Speed Drive SystemsNEMA Standards Publication ICS 7.2-2015Application Guide for AC Adjustable Speed Drive SystemsPublished byNational Electrical Manufacturers Association 1300
2、North 17thStreet, Suite 900 Rosslyn, VA 22209www.nema.org 2015 National Electrical Manufacturers Association. 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 Int
3、ernational and Pan American copyright conventions. 2015 National Electrical Manufacturers AssociationNOTICE AND DISCLAIMERThe information in this publication was considered technically sound by the consensus of persons engaged in the development and approval of the document at the time it was develo
4、ped. Consensus does not necessarily mean that there is unanimous agreement among every person participating in the development of this document.NEMA standards and guideline publications, of which the document contained herein is one, are developed through a voluntary consensus standards development
5、process. This process brings together volunteers and/or seeks out the views of persons who have an interest 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 do
6、es not independently test, evaluate, or verify the accuracy or completeness of any information or the 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 speci
7、al, indirect, consequential, or compensatory, directly or indirectly resulting from the publication, use of, application, or reliance on this document. NEMA disclaims liability for any personal injury, property, or other damages of any nature whatsoever, whether special, indirect, consequential, or
8、compensatory, directly or indirectly resulting from the publication, use of, application, or reliance on this document. NEMA disclaims and makes no guaranty or warranty, express or implied, as to the accuracy or completeness of any information published herein, and disclaims and makes no warranty th
9、at the information in this document will fulfill any of your particular 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
10、 not undertaking to render professional or other services for or 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 adv
11、ice of a competent professional in determining the exercise of reasonable 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
12、by this publication.NEMA has no power, nor does it undertake to 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 heal
13、th- or safety-related information in this document shall not be attributable to NEMA and is solely the responsibility of the certifier or maker of the statement. 2015 National Electrical Manufacturers Association 2015 National Electrical Manufacturers AssociationNEMA ICS 7.2-2015Page iForewordThis g
14、uide was developed by the Motor and Generator Section and the Industrial Automation Control Products and Systems Section and approved for publication as an application guide of the National Electrical Manufacturers Association. This guide is intended to assist users in the proper selection and appli
15、cation of AC adjustable speed drive systems. The guide is revised periodically to provide for changes in user needs, advances in technology, and changing economic trends. All persons having experience in the selection, use, or manufacture of electric motors and adjustable speed drives are encouraged
16、 to submit recommendations that will improve the usefulness of this guide. Inquiries, comments, and proposed or recommended revisions should be submitted to the Motor and Generator Section and the Industrial Automation Control Products and Systems Section by contacting:Senior Technical Director, Ope
17、rations National Electrical Manufacturers Association 1300 North 17thStreet, Suite 900Rosslyn, VA 22209 The best judgment of the Motor and Generator Section and the Industrial Automation Control Products and Systems Section on the performance and construction of adjustable speed drive systems is rep
18、resented in this guide. The guide is based upon sound engineering principles, research, and records of test and field experience. Also involved is an appreciation of the problems of manufacture, installation, and use derived from consultation with and information obtained from manufacturers, users,
19、inspection authorities, and others having specialized experience. For systems intended for general applications, the individual companies through normal commercial contact determined information as to user requirements. Practical information concerning performance, safety, test, construction, and ma
20、nufacture of adjustable speed drive systems is provided in this guide.In the preparation and revision of these standards, consideration has been given to the work of other organizations whose standards are in any way related to adjustable speed drive systems. Credit is hereby given to all whose stan
21、dards may have been helpful in the preparation of this volume.This application guide was developed jointly by the Industrial Automation Control Products and Systems Section and the Motor and Generator Section. Section approval of the guide does not necessarily imply that all section members voted fo
22、r its approval or participated in its development. At the time this guide was approved, the Industrial Automation Control Products and Systems Section was composed of the following members:ABB Control, Inc.Wichita Falls, TX ALSTOM Power ConversionPittsburgh, PA Automatic Switch CompanyFlorham Park,
23、NJ Balluff, Inc.Florence, KY CARLO GAVAZZI, Inc.Buffalo Grove, IL CMC Torque SystemsBillerica, MA Control Concepts CorporationBeaver, PA Cooper BussmannSt. Louis, MO Cummins, Inc.Minneapolis, MN Cyberex LLCMentor, OH Eaton CorporationMilwaukee, WI Echelon CorporationSunnyvale, CA Electro Switch Corp
24、orationWeymouth, MA Elliott Control CompanyHollister, CA Emerson Process ManagementAustin, TX 2015 National Electrical Manufacturers AssociationNEMA ICS 7.2-2015Page iiEntrelec, Inc.Irving, TX GE Industrial SystemsCharlottesville, VA Hubbell IncorporatedMadison, OH Joslyn Clark Controls, Inc.Lancast
25、er, SC Lexington Switch coil: The material wound upon the reel. roll build-up (build-down): The change in roll diameter while winding (unwinding). roll build-up ratio: The ratio of the roll diameter to the empty reel diameter. running tension control: A control function which maintains tension in th
26、e material at operating speeds.service factor (motor): Service factor is defined as a multiplier that, when applied to the rated power, indicates the permissible power loading that may be carried continuously without exceeding a defined temperature rise in the motor.slip: The difference between sync
27、hronous speed and operating speed, at the same frequency, expressed in rpm or in percent or ratio of synchronous speed.speed-range: All the speeds that can be obtained over a defined operating region for a defined load. The speed range is generally expressed as the ratio of the maximum to the minimu
28、m rated speed.stalled tension control: A control function which maintains tension in the material at zero speed.surface winder: A winder in which the roll of material is driven by friction rolls or belts in contact with the outer surface of the roll (see Figure 3-3). taper tension: Provision for var
29、ying tension with build-up, or line speed, or both, as opposed to constant tension. 2015 National Electrical Manufacturers AssociationNEMA ICS 7.2-2015Page 7tension: The total force in pounds or newtons acting on the cross section and tending to cause extension of the material being processed.total
30、power factor: The ratio of the total power input in watts to the total volt-ampere input at the point of connection to the power supply system. Total power factor includes the effect of harmonic components of current and voltage and the effect of phase displacement between current and voltage.total
31、storage: The change in the length of material in the loop as the result of maximum loop travel. total storage time: The total storage divided by the maximum rated line speed, expressed in seconds. voltage boost: An additional amount of control output voltage, above the value based on constant volts
32、per Hz, applied at any frequency. It is generally applied at lower frequencies to compensate for the voltage drop in the stator winding.volts/Hz ratio: The volts/Hz (volts per Hz) ratio is the ratio of fundamental voltage to frequency.voltage source inverter: For the purpose of this guide, a voltage
33、 source inverter produces variable frequency AC from a constant voltage DC bus.Figure 3-1 OPERATING LOOP TRAVEL 2015 National Electrical Manufacturers AssociationNEMA ICS 7.2-2015Page 8Figure 3-2 CENTER WINDER (UNWINDER)Figure 3-3 SURFACE WINDER 2015 National Electrical Manufacturers AssociationNEMA
34、 ICS 7.2-2015Page 9Section 4DESCRIPTION OF SYSTEM COMPONENTS4.1 LOAD TYPESIn most processes the load varies with speed as described using one of the following terms: variable torque loads, constant torque loads, and constant horsepower loads. When applying a control and motor to a process, it is imp
35、ortant to determine how the load is related with speed.4.1.1 Variable TorqueVariable torque loads are good candidates to apply ASDs for energy savings. Typical examples of such loads are centrifugal pumps, centrifugal fans, centrifugal blowers, and centrifugal compressors.4.1.1.1 Squared Torque Vari
36、ation A variable torque load having a squared relationship means that the torque varies at a rate proportional to the square of the speed and horsepower varies as the cube of the speed, reaching 100 percent load torque and horsepower at a defined speed. (See Figure 4-1.)SQUARED TORQUE VARIATION0.000
37、.250.500.751.001.250.00 0.25 0.50 0.75 1.00 1.25Per Unit of Base SpeedPer Unit Torque or HP of Driven LoadTorqueHorsepowerFigure 4-1 SQUARED TORQUE VARIATION4.1.1.2 Linear Torque VariationA variable torque load having a linear relationship means that the torque varies linearly with speed and horsepo
38、wer varies as the square of the speed, reaching 100 percent load torque and horsepower at a defined speed. (See Figure 4-2.) 2015 National Electrical Manufacturers AssociationNEMA ICS 7.2-2015Page 10LINEAR TOURQUE VARIATION0.000.250.500.751.001.250.00 0.25 0.50 0.75 1.00 1.25Per Unit of Base Speed P
39、er Unit Torque and HP of Driven LoadTorqueHorsepowerFigure 4-2 LINEAR TORQUE VARIATION4.1.2 Constant TorqueFor constant torque loads, the load torque remains constant throughout the speed range, as shown in Figure 4-3. The horsepower changes linearly with speed for these loads.Machines that are high
40、-impact loads or duty-cycle loads typically fall into the constant torque classification. Conveyors, process lines (strip, web, and sheet), augers, positive displacement pumps, extruders, crushers, screw compressors, reciprocating compressors, and ball mills are examples of constant torque loads. 20
41、15 National Electrical Manufacturers AssociationNEMA ICS 7.2-2015Page 11CONSTANT TORQUE LOAD0.000.250.500.751.001.250.00 0.25 0.50 0.75 1.00 1.25Per Unit of Base Speed Per Unit Torque and HP of Driven LoadTorqueHorsepowerFigure 4-3 CONSTANT TORQUE LOAD4.1.2.1 Duty CycleA duty cycle consists of discr
42、ete loads applied for defined periods of time repeated periodically. The discreet loads may be at changing or constant speeds. (See Figure 4-4.) A typical duty cycle definition consists of speed and load versus time. An example would be a material handling conveyor system.TimeLoad t1 t2 t3 t5 t6 t7A
43、ccelAccelDecelDecelRun RunOfft4Offt8Speed Figure 4-4 DUTY CYCLES4.1.2.2 High Impact LoadWith an impact load, the torque loading is intermittent and is not a function of speed. Impact loads are exhibited by a punch press, which uses a large flywheel to deliver the energy needed for the load. It is 20
44、15 National Electrical Manufacturers AssociationNEMA ICS 7.2-2015Page 12also characteristic of loads that are driven through a clutch, which is cycled during the process operation. Press applications require that the motor and control combination produce sufficient accelerating torque to return the
45、flywheel to the required speed prior to the beginning of the next work stroke. (See Figure 4-5.)TorqueABCTimeDTimeMotor SpeedA -Peak Torque B -Motor TorqueC -Friction TorqueD -Motor SpeedE -Machine load EFigure 4-5 IMPACT LOAD4.1.3 Constant HorsepowerFor constant horsepower loads, the load torque dr
46、ops as speed increases resulting in constant horsepower throughout the speed range, as shown in Figure 4-6.Center driven winders and machine tools (where heavier cuts are taken at lower speeds and lighter cuts at higher speeds) are examples of constant horsepower loads. 2015 National Electrical Manu
47、facturers AssociationNEMA ICS 7.2-2015Page 13CONSTANT HORSEPOWER LOAD0.000.250.500.751.001.250.00 1.00 2.00 3.00 4.00Per Unit of Base Speed Per Unit Torque and HP of Driven Load TorqueHorsepowerFigure 4-6 CONSTANT HORSEPOWER LOAD4.2 MOTOR TYPES4.2.1 GeneralPerformance requirements for various types
48、of induction motors for use on standard sinewave power supplies are identified in NEMA MG1. Some of these types of motors are suitable for use in variable speed applications, dependent on the type of application. Performance requirements are also identified for motors for specific use in variable sp
49、eed applications. The purpose of this section is to provide guidance on the selection of one or more of the types of motors identified in NEMA MG1 that may be appropriate for the particular variable speed application under consideration. See Figure 4-7.4.2.2 Design ANEMA MG1 does not impose any limits on the magnitude of the locked-rotor current on Design A motors, other than that the locked-rotor current is greater than the upper limit for Design B motors. They are usually used in situations where higher locked-rotor current is used for the purpose of obtai
