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Industry Applications, IEEE Transactions on

Issue 5 • Date Sept.-Oct. 1997

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Displaying Results 1 - 25 of 35
  • Discussion of "Survey results of low-voltage circuit breakers as found during maintenance testing: working group report"

    Page(s): 1370 - 1371
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    The author argues that the original paper (C.J. O'Donnell, see ibid., vol. 33, no. 5, p. 1367-9, 1997) can provide some useful insight for the user and specifier of these products, but argues that it is important to keep in mind some of the limitations on the data as collected. As was determined at the discussion following the presentation of the paper, he states how the paper covers only tests which were performed on low voltage power circuit breakers as covered by ANSI Standard C37.16 and does not include any data from testing of low voltage molded case circuit breakers. Thus, he believes the title of the report should be corrected to reflect the actual type of breakers included and the applicable standard. He also lists other areas in the report which he believes should be strongly considered when evaluating the validity or reliability of the data presented. View full abstract»

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  • Energy-efficient induction motors performance characteristics and life-cycle cost comparisons for centrifugal loads

    Page(s): 1312 - 1320
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (208 KB)  

    When fixed-speed motors (fed directly at power frequency) are purchased for new installations or for replacements, the loaded shaft speed differences among motor options are either ignored or overestimated. The most common first-cut estimate is that the consumed shaft power will vary as the cube of the ratio of the motor rated nameplate speeds for centrifugal driven loads that have discharge control valves (on pressure or now control). In actuality, this is true only if the motors are loaded at approximately nameplate output. This paper discusses the true “control valve loss” factor taking into account actual speed differences among motor options. A simplified equation and figure are presented to permit quick evaluation of motor purchase alternatives for the lowest life-cycle cost based on efficiency and rated-load speed differences. NEMA standards on slip-speed variation should be made more stringent to increase the validity of speed-difference loss evaluations. Additionally, efficiency test results and loaded speed measurements for standard-efficiency and premium-efficiency 10 and 100 hp motors are presented, leading to a conclusion that standard-efficiency motors should be operated at no higher than rated voltage and that premium-efficiency motors should he operated at 5%-10% above rated voltage for best system efficiency View full abstract»

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  • Improved constant-frequency hysteresis current control of VSI inverters with simple feedforward bandwidth prediction

    Page(s): 1194 - 1202
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (276 KB)  

    An improved implementation of the constant-frequency hysteresis current control of three-phase voltage-source inverters is presented. A simple, self-adjusting analog prediction of the hysteresis band is added to the phase-locked-loop control to ensure constant switching frequency, even at a high rate of output voltage change, such as required in active filters, fast drives and other highly demanding applications. This provision also improves the relative position of phase modulation pulses, thus reducing the current ripple. The prediction method is robust and uses a small number of inexpensive components. It does not require trimming or tuning, giving the whole system the capability to adjust itself to different load conditions. Thus, the control becomes suitable for hybrid or monolithic integration. In this paper, the basic principles are described, and a detailed stability analysis is carried out. The control performance is illustrated, both by simulated and experimental results View full abstract»

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  • Improved zero-current transition converters for high-power applications

    Page(s): 1220 - 1232
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (304 KB)  

    Existing zero-current transition (ZCT) converters do not solve main switch turn-on problems and require auxiliary switches to be turned off with high current and, therefore, are not suitable for high-power applications. Novel ZCT schemes proposed in this paper enable all main switches and auxiliary switches to be turned on and off under zero-current conditions. The zero-current switching at both turn-on and turn-off not only reduces switching losses significantly, but also eliminates the need for passive snubbers, due to the much reduced switch stress. The cost of the auxiliary switches can he reduced compared to the existing ZCT schemes, due to their zero-current turnoff. The proposed technology is well suited for DC-DC and three-phase converters with insulated gate bipolar transistors (IGBTs), MOS-controlled thyristors (MCTs), and gate-turnoff switches (GTOs). Theoretical analysis, computer simulation, and experimental results are presented to explain the proposed schemes View full abstract»

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  • Servers in SCADA applications

    Page(s): 1295 - 1299
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    Data acquisition and supervisory control and data acquisition (SCADA) systems have evolved from mainframe-based systems to multilevel tiered systems to flat client-server architecture. This paper examines the necessity for this evolution and the technology that spurred it on. A rod mill is discussed as a case study View full abstract»

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  • Survey results of low-voltage circuit breakers as found during maintenance testing: Working Group report

    Page(s): 1367 - 1369
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (56 KB)  

    The Power Systems Reliability Subcommittee strives to maintain current reliability data on major electrical equipment to assist the industry in accomplishing realistic and meaningful reliability studies. This paper presents the results of a low-voltage circuit breaker reliability survey achieved through the use of available results from testing during preventive maintenance. A substantial number of test results were obtained to allow credible results for a few different circuit breaker categories. A similar set of results was published by Kornblit (1990). Most of these results have been incorporated into this new expanded effort View full abstract»

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  • Single current sensor technique in the DC link of three-phase PWM-VS inverters: a review and a novel solution

    Page(s): 1241 - 1253
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (308 KB)  

    A review of the existing methods to determine the output currents in a pulsewidth modulation voltage-source (PWM-VS) inverter using a single current sensor in the DC link is presented, and a novel solution is proposed. The unique arrangement of the DC link allows full protection of the inverter from short circuits and overloads. Also, a new method of sampling the DC-link current is described that produces true values of the output currents at the centers of switching intervals. Results of investigation of an experimental setup have shown that full protection of the inverter has been accomplished and the output currents can accurately be determined within the whole operating area View full abstract»

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  • Design of a low-input-voltage converter for thermoelectric generator

    Page(s): 1203 - 1207
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    Low-grade exhaust heat is used to provide a reliable and independent power source for instrumentation circuitry by means of a thermoelectric generator (TEG). A design of a self-starting DC-DC power converter is developed and optimized for very-low-input voltages (below 300 mV) in order to allow operation at temperature differences of 20°C and less. A prototype is built, and the results are experimentally verified View full abstract»

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  • A novel single-switch-per-phase converter topology for four-quadrant PM brushless DC motor drive

    Page(s): 1154 - 1161
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (164 KB)  

    Considerable attention has been given to finding compact and low-cost converter topologies for permanent magnet (PM) brushless motor drives to meet the emerging high-volume low-performance applications, such as in HVAC, air handlers, fans, pumps, small process drives, hand tools, appliance drives, and many others in the range of fractional to 1-hp rating. This paper is concerned with such an attempt to formulate a novel converter topology for a four-quadrant PM brushless DC (PMBDC) motor drive. The proposed topology has a single switch per phase, limiting the motor drive to half-wave operation. However, it also endows unique features with high reliability, such as shoot-through-free topology by having a switch always in series with a phase winding, operational possibilities, even with one- or two-phase windings failure, reducing the converter losses to half that of the full-wave inverter, reduction of gate drivers and amplifiers, and reduction in the logic power supplies requirement. Many of these features result in low cost and compact packaging of the converter for the PM brushless DC motor drive. The machine design modification requirement due to the half-wave operation of the proposed converter is derived in this paper to help in the realization of the proposed motor drive in industrial applications. The formulation and description of the circuit topology and its operation with the motor, their dynamic modeling, simulation and analysis, and its comparison to the full-wave-inverter-fed PMBDC motor drive are the key contributions of this paper View full abstract»

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  • About the possibility of defining a standard method for iron loss measurement in soft magnetic materials with inverter supply

    Page(s): 1283 - 1288
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    Due to the increase of electromagnetic and electromechanical devices supplied by static converters, the classification and evaluation of the energetic behavior of soft magnetic materials, with nonsinusoidal supply, is becoming mandatory. In this paper, the possibility of defining a standard methodology for the specific iron loss measurement (iron losses per mass unity), with static supply, is analyzed. In particular, the paper underlines the main problems which can be found when standard magnetic measurements are carried out with nonsinusoidal sources. Pulsewidth modulation (PWM) inverters can be considered an industrial standard solution as a static supply source. As a consequence, the problems linked to the use of this kind of supply with magnetic material have been analyzed, taking into account the effects due to the PWM inverter characteristics (for example, modulation index, switching frequency, and modulation technique). In addition, in the paper, a basic structure of a standard test bench is proposed, also taking into consideration the required instrumentation View full abstract»

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  • A comparison between insulation systems available for PWM-inverter-fed motors

    Page(s): 1331 - 1341
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    This paper establishes the need for two levels of motor insulation systems depending upon the available voltage waveform. An analysis of the various winding stresses is presented. The different requirements for the two insulation systems are discussed (MG1-Parts 30 and 31 For General Purpose and Definite Purpose Inverter Fed Motors), and test results show the need for higher dielectric insulation when the voltage levels of Part 30 are exceeded. The differences between existing, rebuilt and new motors are also explored View full abstract»

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  • Closure to discussion of “Survey results of low-voltage circuit breakers as found during maintenance testing: Working Group report”

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    The original authors' reply to a discussion of his paper “Survey results of low-voltage circuit breakers as found during maintenance testing: Working Group report” are presented in this paper View full abstract»

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  • Stator-flux-oriented sensorless induction motor drive for optimum low-speed performance

    Page(s): 1170 - 1176
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (208 KB)  

    For high-performance AC drives, the speed-sensorless vector control of induction motors has received increasing attention from the standpoints of cost, size, noise immunity, and reliability. This paper presents the speed- and voltage-sensorless drive of vector-controlled induction motors for general-purpose drive applications. The rotor speed is determined by the difference between the synchronous angular frequency and the estimated slip angular frequency, which is estimated by the detected stator current and the stator-flux reference. To improve the low-speed drive characteristics, accurate applied-voltage calculation is proposed under considerations of the compensations for the quantization error in the digital controller, the forward voltage drop of switching devices, and the dead time of the inverter. The experimental studies show the improved drive characteristics View full abstract»

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  • Tentative criteria for the design and installation of electrical power systems subject to seismic hazard

    Page(s): 1342 - 1347
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    This paper discusses the need to study the criteria for the design and installation of electrical power systems in buildings subject to seismic hazards. Nowadays, all the recommended seismic requirements (according to the Uniform Building Code [UBC], Structural Engineers Association of California [SEAOC] and National Earthquake Hazards Reduction Program [NEHRP]) do not specifically take into account the electrical or technological power systems. This paper analyzes the problems an earthquake can cause with regard to the functional reliability and continuity of supply of electrical power systems. Therefore, it proposes design and installation requirements, to be graduated according to building occupancy categories. Basically, the criteria relative to the installation of the electrical equipment are an appropriate extension of those general static ones for nonstructural components. Their consideration is essential for the settlement of the design criteria, which, as far as the configuration and the size of the electrical power system are concerned, aim at limiting the same installation problems. Other general design criteria, designed as a guarantee for supply continuity and power system reliability, have a particular use in these appliances View full abstract»

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  • Applicability of neural networks to industrial and commercial power systems: a tutorial overview

    Page(s): 1355 - 1361
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    This paper is intended as a tutorial overview of neural network applications that are relevant to industrial and commercial power systems. The paper is arranged to provide the practicing engineer with answers to the following questions: (1) why would a neural network be needed?;(2) what is required to use a neural network?; (3) how are neural networks superior to conventional methods?; and (4) what type of results are produced by neural networks? Introductory knowledge needed for understanding the application of artificial neural networks is provided and numerous example applications are referenced. The paper is purposefully written without “state-of-the-art” terminology for the benefit of practicing engineers in facilities today who may not be familiar with neural networks. This paper is expected to be the first in a series that will provide a similar presentation of expert and fuzzy-logic systems View full abstract»

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  • 200°C operation of a 500-W DC-DC converter utilizing power MOSFETs

    Page(s): 1267 - 1272
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    This paper presents results from the operation of the power stage of a 500-W DC-DC converter at an ambient temperature of 200°C. This converter is designed to provide an output voltage of 12-Vdc from a 28-Vdc input. It utilizes an H-bridge configuration composed of eight International Rectifier power MOSFETs (parallel connections of two MOSFETs) and four Motorola diodes to convert the DC input voltage to a high-frequency square wave which can then be stepped up with a transformer. The transformer output voltage is then rectified and filtered to produce the DC output voltage. A phase-shifted pulse-width modulation (PWM) switching scheme is utilized to control the MOSFETs in the H bridge. This scheme allows zero-voltage turn-on of the MOSFETs to improve the efficiency. The efficiency of this converter when operated on the laboratory bench was measured to be 89%. The H bridge and transformer were then placed in an oven and operated over an ambient temperature range of 20°C-200°C. The efficiency varied from 86.1% to 85.4% over this temperature range. The long feedthroughs for oven operation caused the efficiency to decrease from 89% to 86.1% View full abstract»

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  • An economical, high-temperature, impedance heat exchanger

    Page(s): 1300 - 1306
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (196 KB)  

    This paper outlines the methods used to design an impedance-heated fluid heat exchanger used in the petrochemical industry. It provides suggestions for determining the method to transfer heat from pipe walls to fluid, to choose electrical pipe wall heating, and to select electrical controls. The paper also provides actual operating data and includes cost and operating advantages of this type of heat exchanger View full abstract»

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  • A new method to linearize any triangle-comparison-based PWM by reshaping the modulation command

    Page(s): 1254 - 1259
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (208 KB)  

    A new method, which linearizes any triangle-comparison-based pulsewidth modulation (PWM) in the pulse-dropping region, is presented. Based on the original modulating command, the method produces a modified command as a function of the modulation index. This modified command compensates for the volt-sec which are lost due to a portion of the original modulating command exceeding the boundaries of the triangle carrier. The method eliminates the need to overmodulate in the pulse-dropping region and prevents erosion of the dynamic range of the associated control. This method is applied to three common PWM algorithms. Analytical expressions are derived for each case and verified on a 100 kW AC/DC converter View full abstract»

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  • Pulsed-plasma treatment of polluted gas using wet-/low-temperature corona reactors

    Page(s): 1373 - 1380
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    Application of pulsed plasma for gas cleaning is gaining prominence in recent years, mainly from the energy consideration point of view. Normally, the gas treatment is carried out at or above room temperature by the conventional dry-type corona reactor. However, this treatment is still inadequate for the removal of certain stable gases present in the exhaust/flue gas mixture. The authors report here some interesting results of the treatment of such stable gases like N2 O with pulsed plasma at subambient temperature. Also reported in this paper are improvements in DeNO/DeNOx efficiency using unconventional wet-type reactors, designed and fabricated by us, and operating at different subambient temperatures, DeNO/DeNOx by the pulsed-plasma process is mainly due to oxidation, but reduction takes place at the same time. When the wet-type reactor was used, the NO 2 product was absorbed by water film and higher DeNOx efficiency could be achieved. Apart from laboratory tests on simulated gas mixtures, field tests were also carried out on the exhaust gas of an 8-kW diesel engine. A comparative analysis of the various tests are presented, together with a note on the energy consideration View full abstract»

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  • A multilevel thyristor rectifier with improved power factor

    Page(s): 1208 - 1213
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    The thyristor bridge rectifier is a reliable and cost-effective topology commonly used in medium-voltage applications. Low and load-varying input displacement factor (IDF) and poor input harmonic current profile are the main drawbacks of this topology and are gaining more and more importance. This paper proposes modification of a conventional (18-pulse) thyristor rectifier to achieve higher power factor. The proposed topology employs one gate-turn-off (GTO) device across each upper bridge to short them out when necessary, hence, lowering the voltage level, decreasing the delay angle, and improving the power factor. In medium voltage (4160-V) AC drives, usually three devices are connected in series to withstand the voltage; therefore, the 18-pulse configuration has the same number of SCRs as compared to a six-pulse bridge. This paper includes analysis, simulation, and a comparison of the proposed topology with the conventional 6-, 12-, and 18-pulse thyristor bridges. Experimental results from a 10-kVA 12-pulse system verify the feasibility of the proposed topology View full abstract»

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  • Sensorless position detection for vector-controlled induction motor drives using an asymmetric outer-section cage

    Page(s): 1162 - 1169
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (168 KB)  

    This paper describes a new method of obtaining a rotor position signal from a cage induction machine operating without a mechanical sensor. The method is based on introducing a circumferential variation in the resistance of a high-resistance outer-section cage of an induction-machine rotor. Simulation results using a linear “double-cage” machine equivalent show that the method is feasible and provides incremental rotor position tracking with good dynamics. The paper describes an implementation of the method for a 30 kW double-cage machine having variable-gauge copper wire in the outer slots. It is shown that, while the rotor position-dependent signals are robust to changes in load, interference harmonics arising from slot saturation and rotor slot harmonics cause problems for rotor position tracking. These problems are discussed in relation to the present method and that of designed asymmetries in general View full abstract»

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  • A new era in cable designs and materials to resolve environmental issues

    Page(s): 1321 - 1330
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (156 KB)  

    In recent years, environmental issues have had a profound influence on power cable designs and materials used in cable construction. This paper addresses the issues concerned with the effects of cables on the environment, as well as the effects of environmental conditions on cable performance and reliability. Effects on the environment include release of toxic materials and contamination of ground water. Environmental effects on cables are related to the presence of moisture, chemicals, ions, oils or solvents. All such issues must be considered in the evolution of environmentally-safe cables. This also extends to the manufacturing processes for producing cable insulation, jacketing and sheathing materials, as well as the cable manufacturing process itself. New cable designs and materials have been developed to mitigate many of the more serious environmental issues now associated with cable applications. Such designs and associated materials are reviewed in this paper. Emphasis is placed on the safeguards protecting the environment and on extending cable life and performance. These safeguards include technological advances in insulation, shielding, jacketing and sheathing materials, as well as new cable designs that cable specifiers should take into consideration when properly selecting and applying power cables for petroleum and chemical plant installations. Other user concerns that include cable diameter, short-circuit withstand, mechanical performance, installation, splices and terminations are briefly reviewed as they relate to current cable technology View full abstract»

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  • Modeling and analysis of a wide-speed-range induction motor drive based on electronic pole changing

    Page(s): 1177 - 1184
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    It has been previously demonstrated that an induction machine drive with contactorless pole changing can be achieved by reversing the current directions of certain stator coil groups. This paper compares the power and torque capability of this type of induction motor drive with conventional four-pole and two-pole induction machine drives. Based on the technique of vector space decomposition, the machine coupled-circuit model is transformed into a reference frame model. As a result of this transformation, the coupled coil group variables can be replaced by equivalent decoupled four-pole and two-pole dqO variables. This reference frame model facilitates the analysis and control of the machine drive, especially during transients, such as the pole-changing transition View full abstract»

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  • A new modulation technique for reducing the input current harmonics of a three-phase diode rectifier with capacitive load

    Page(s): 1185 - 1193
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (244 KB)  

    In this paper, a new technique for shaping the line current and reducing the total harmonic distortion in a three-phase bridge rectifier, feeding a capacitive load, is presented. Using the topology of a three-level three-switch pulsewidth modulated (PWM) rectifier, a new control technique has been implemented. The main objective here is to minimize the total harmonic distortion (THD) of the line current under different load conditions (20%-100% of full load). A review of the problems inherent in a bridge rectifier feeding a capacitive load and the possible solutions are first presented. Subsequently, the analysis of the new circuit and the control technique used are described, along with simulation results. Finally, the experimental results on a 1.6 kW prototype are presented View full abstract»

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  • Multimodular multilevel converters with input/output linearity

    Page(s): 1214 - 1219
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    Multilevel converters constitute the key technology of power electronics to reach the high power ratings required by controllers of flexible AC transmission systems (FACTS). This paper shows that the sinusoidal pulsewidth modulation (SPWM) technique, as applied to multilevel converters, inherently requires a high switching rate. The paper then presents a strategy based on multiple modules of multilevel converters which operate with the lowest possible switching loss (each gate-turn-off thyristor (GTO) switches ON and OFF only once during the modulation period), while maintaining the high gain-bandwidth product of linear amplifiers to handle fast feedbacks, which FACTS controllers must be capable of, in order to carry out dynamic performance enhancement View full abstract»

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Aims & Scope

The scope of the IEEE TRANSACTIONS ON INDUSTRY APPLICATIONS includes all scope items of the IEEE Industry Applications Society, that is, the advancement of the theory and practice of electrical and electronic engineering in the development, design, manufacture, and application of electrical systems, apparatus, devices, and controls to the processes and equipment of industry and commerce; the promotion of safe, reliable, and economic installations; industry leadership in energy conservation and environmental, health, and safety issues; the creation of voluntary engineering standards and recommended practices; and the professional development of its membership.

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