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Industry Applications, IEEE Transactions on

Issue 2 • Date March-April 1995

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Displaying Results 1 - 25 of 28
  • Comments on "Harmonics: the effects on power quality and transformers"

    Publication Year: 1995 , Page(s): 405 - 406
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (211 KB)  

    The author comments on the paper by R.D. Henderson and P.J. Rose (see ibid., vol.30, no.3, 1994) suggesting that four points are subject to misinterpretation. These are related to: mixed references to voltage harmonics and current harmonics; K-rated transformers; transformer derating factor; and harmonics attenuation by an isolation transformer. The authors of the original article reply to the comments.<> View full abstract»

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  • AC/DC/AC PWM converter with reduced energy storage in the DC link

    Publication Year: 1995 , Page(s): 287 - 292
    Cited by:  Papers (104)  |  Patents (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (456 KB)  

    The paper introduces the family of quasi-direct converters, i.e., forced-commutated AC/DC/AC power converters including small energy storage devices in the DC link. In particular, the case of the three-phase to three-phase quasi-direct power converter is considered. Since energy storage minimization calls for instantaneous input/output power balance, a proper control strategy is needed. The paper describes a simple and effective control technique which also provides high-power factor and small distortion of the supply currents. After a discussion of the general properties of quasi-direct power converters, design criteria of both power and control sections are given, and experimental results of a 2-kVA prototype are reported View full abstract»

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  • Faults and unbalance forces in the switched reluctance machine

    Publication Year: 1995 , Page(s): 319 - 328
    Cited by:  Papers (54)  |  Patents (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (756 KB)  

    The paper identifies and analyzes a number of severe fault conditions that can occur in the switched reluctance machine, from the electrical and mechanical points of view. It is shown how the currents, torques, and forces may be estimated, and examples are included showing the possibility of large lateral forces on the rotor. The methods used for analysis include finite-element analysis, magnetic circuit models, and experiments on a small machine specially modified for the measurement of forces and magnetization characteristics when the rotor is off-center. Also described is a computer program (PC-SRD dynamic) which is used for simulating operation under fault conditions as well as normal conditions. The paper discusses various electrical configurations of windings and controller circuits, along with methods of fault detection and protective relaying. The paper attempts to cover several analytical and experimental aspects as well as methods of detection and protection View full abstract»

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  • Unified theory of torque production in switched reluctance and synchronous reluctance motors

    Publication Year: 1995 , Page(s): 329 - 337
    Cited by:  Papers (30)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (744 KB)  

    A method is described for calculating the average and instantaneous torque of the synchronous reluctance motor from a knowledge of the trajectory of the phase flux-linkage versus phase current [i-ψ] waveform, i.e., the same method as used with the switched reluctance motor. This allows a direct comparison between torque production in the two motors to be made. Analytical and finite-element analysis both show that the [i-ψ] loci of the synchronous reluctance motor are ellipsoidal in shape and are not limited to the first and third quadrants as in the switched reluctance motor. The [i-ψ] loci of the synchronous reluctance motor are not bounded by the magnetization curves in the same sense as in the switched reluctance motor and rely upon mutual coupling between phases for correct operation View full abstract»

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  • Effect of transformer sizes and neutral treatments on the electromagnetic transients in transformer substations

    Publication Year: 1995 , Page(s): 384 - 391
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (524 KB)  

    This paper deals with the electromagnetic transients in transformer substations. The substation can have more than one transformer. Generally, these parallel-connected transformers can be of different sizes and neutral treatment. The substation is fed from a high-voltage overhead transmission line (or cable). Emphasis is given to the substation terminal voltage, the transformers' neutral voltages (if their neutrals are not directly earthed) as well as the internal distribution of transient voltages along the transformers' windings, following a typical external double-exponential surge voltage. The distributed parameter transient analysis is done in the s-domain, and then followed by a numerical Laplace inverse transform technique to get the distributions in time domain View full abstract»

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  • Quick evaluation of voltage surge in electrical power systems

    Publication Year: 1995 , Page(s): 379 - 383
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (316 KB)  

    The lattice diagram has been widely recognized and adopted to analyze the voltage surges produced at a particular location in an electrical system. These transient surges are caused by traveling waves induced by lightning strokes or switching operations. A lattice diagram can be used effectively, but the required computations are tedious. A simplified approach based on mathematical derivation is presented. The method will permit a quick evaluation of both initial and crest surge magnitudes as well as a wave shape that are all based on a given incoming surge and the surge impedances of the electrical elements involved. Sample calculations from the lattice diagram and the proposed quick evaluation are compared View full abstract»

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  • Modeling and control of magnet power supply system with switch-mode ripple regulator

    Publication Year: 1995 , Page(s): 264 - 272
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (648 KB)  

    This paper presents the dynamic performance analysis and closed-loop design of a new power supply system for a high-current magnet load. This new system introduces a series switch-mode ripple regulator (SMRR) into a phase-controlled rectifier to improve system dynamic response and to reduce the harmonic content in the magnet current. In this paper, the new system control configuration is explained. The small signal dynamic model is established. The function of the SMRR as a speed-up feed-forward path during dynamic transients is assessed. The criteria of the closed-loop regulator design are identified. The theoretical analyses are accompanied by computer simulation and experimental results. The systematical design procedure is outlined by an example which offers better performance than ever reported on high-current magnet power supplies in terms of fast dynamic response (closed-loop bandwidth several kHz) and low harmonic content (less than 10 ppm) in the magnet current View full abstract»

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  • Selection of the pole number of induction machines for variable speed applications

    Publication Year: 1995 , Page(s): 304 - 310
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (632 KB)  

    The selection of the pole number for induction motors supplied from a constant frequency source is straightforward because the pole number is determined solely by the synchronous speed required for the application. However, the selection of the pole number for inverter-driven induction motors is much more involved because the pole number is not determined by a single, dominating factor in these cases. In principle, any even number can be chosen as the pole number because the frequency can be adjusted and therefore the synchronous speed can be controlled to have any desired value. For these applications, the selection of the pole number typically involves numerous factors and trade-offs, many of which are identified and their influence on parameters and performance described in this paper. Some general conclusions on the selection of pole number are also presented View full abstract»

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  • Experiences with clinker grinding in roller mills

    Publication Year: 1995 , Page(s): 413 - 418
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (636 KB)  

    The experiences of applying roller mills to the production of finely ground products such as cement and slag are presented and reviewed. The unique process and operating conditions which need to be controlled and their impact on the success of the system are also discussed. The range of mill design features which are being used today are shown and compared. The increase in the number and size of the finish grinding roller mills installed relates to their successful field experiences, reduced power requirements, increased confidence in reliability and simplicity of the installations View full abstract»

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  • Achieving a constant power speed range for PM drives

    Publication Year: 1995 , Page(s): 368 - 372
    Cited by:  Papers (5)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (464 KB)  

    Flux weakening has long been a standard approach in obtaining a constant power speed range for traction drives with commutator motors. There is much interest in using permanent magnet (PM) commutator motors or, preferably, electronically commutated PM motors for such applications. Some PM motor designs, such as those using inset or buried magnets, have been proposed to achieve flux weakening. This paper questions the desirability of the flux weakening approach for a number of applications where energy efficiency is of prime importance, such as in electric vehicles. For an acceptable increase in the rating of some of the semiconductor devices, standard PM commutator motors and switched PM motors with surface-mounted magnets can be used and a significant reduction in power loss can be achieved View full abstract»

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  • Impact of IGBT behavior on design optimization of soft switching inverter topologies

    Publication Year: 1995 , Page(s): 280 - 286
    Cited by:  Papers (11)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (588 KB)  

    IGBTs operated under a zero voltage switching scheme exhibit significantly different operating characteristics from specified parameters in manufacturer data sheets. Important differences include an elevated tail current, dynamic saturation and resulting snubber dump, and a significantly higher conduction loss under moderate to high di/dt conditions. Soft switching inverter topologies of various kinds have been reported in the literature including resonant DC and AC link inverters, resonant pole inverters and many variations thereof. Loss characterization of soft switching inverter circuits reported to date is based on manufacturer data sheets, and do not reflect actual losses incurred in the circuit. Including the actual device behavior into the circuit loss calculations has a big impact on the total losses, and more importantly the trade-offs which impact the viability of a given topology at a specified operating point. This paper presents a detailed analysis of the losses in soft switching inverters and the impact on topology choice. A detailed design of a 50 kVA IGBT-based resonant DC link inverter is used as a design example, and it is seen that optimal design points and choices are significantly different from those that have been reported earlier View full abstract»

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  • Soft-switched PWM converter with inductive DC filter

    Publication Year: 1995 , Page(s): 293 - 298
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (500 KB)  

    This paper presents a soft-switched AC/DC power converter structure, useful for current-fed inverters and forced-commutated PWM rectifiers with inductive loads. Typical applications are high-power AC motor drives, magnet power supplies and active power filters with inductive energy storage. As compared to hard-switched power converters, the proposed solution calls for some increase of the circuit complexity, but provides improved input and output performances due to the higher switching frequency. Further improvements are ensured by proper control of the commutation process. Actual power converter capabilities are demonstrated by experimental results View full abstract»

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  • Temperature effects on torque production and efficiency of PM motors using NdFeB magnets

    Publication Year: 1995 , Page(s): 353 - 357
    Cited by:  Papers (56)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (384 KB)  

    Recent developments in high energy magnets have created widespread interest in the area of permanent magnet (PM) motors. The use of PM synchronous motors or brushless motors to replace conventional DC or induction type motors has not been as speedy as anticipated earlier. This paper deals with the temperature effects of PM motors using neodymium magnets on the torque production capability and on the efficiency of the motor. When PM motors are designed to operate in a wide temperature range, the reversible demagnetization of the neodymium magnets with temperature and the increase in winding resistance with temperature influence the maximum torque capability at rated speed and efficiency of the PM motor. The maximum torque at rated speed is limited due to the fixed DC link voltage of the inverter feeding the motor. In this paper, it is shown that over an operating range of -40°C to 150°C the maximum torque capability and efficiency of the motor can vary over a wide range. It is also shown that for certain designs, a near flat maximum torque versus temperature characteristic may be obtained. The major factors influencing these variations are identified. The discussion in this paper is concentrated on PM motors with a trapezoidal back EMF waveform. The idea could be extended to sinusoidal back EMF motors and to PM DC motors View full abstract»

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  • Integrator backstepping techniques for the tracking control of permanent magnet brush DC motors

    Publication Year: 1995 , Page(s): 248 - 255
    Cited by:  Papers (10)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (712 KB)  

    An integrator backstepping technique is introduced for the design of high-performance motor controllers. The approach is applied to the design of embedded computed torque and output feedback controllers for permanent magnet brush DC (BDC) motors. The proposed controllers are simulated and experimentally verified on a user-developed digital signal processor (DSP) based data acquisition and control (DAC) system. Although the BDC motor is well researched, the results motivate extensions of the proposed techniques to the development of similar controllers for more complex electromechanical systems, such as separately excited DC, permanent magnet stepper, brushless DC, switched reluctance, and AC induction servo motors View full abstract»

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  • Relay performance considerations with low-ratio CTs and high-fault currents

    Publication Year: 1995 , Page(s): 392 - 404
    Cited by:  Papers (14)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1080 KB)  

    Low-ratio toroidal current transformers (CTs) are in existence in many locations on power systems. The majority of these CTs are in the auxiliary switchgear at generating stations, but are not limited to this application. The ratio of the CTs used in this application is usually selected to accommodate metering and overload protection. The problem addressed is the absence of consideration in this ratio selection for fault protection. In many cases the fault duty of this switchgear is very high and, because the low-ratio CTs also are of low accuracy classes, the CTs will saturate during a fault. The analysis of some fault cases shows that the protective relaying will not operate, or will not operate properly, due to the saturated CTs. The significance and consequences of the use of these CTs and the accompanying saturation during high-fault currents are discussed. Considerations when testing low-ratio CT applications for saturation are presented as well as a computer program to demonstrate the volt-time concept of CT saturation. Alternate CT connections and corrective alternatives are given along with conclusions to aid in resolving low-ratio/high-fault current situations View full abstract»

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  • Electronic welder with high-frequency resonant inverter

    Publication Year: 1995 , Page(s): 273 - 279
    Cited by:  Papers (13)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (592 KB)  

    This paper presents a new generation of electronic welders, incorporating soft-switched inverters driving high-frequency transformers. They are light, reliable, flexible, and offer good efficiency, fast response, and control robustness. A control strategy able to ensure correct operation in any load and supply condition, small stand-by loss, and automatic recovery from line failures is discussed. Experimental results of an industrial prototype rated for 80 V (no-load voltage), 130 A (full-load current), and 80-kHz switching frequency are also presented View full abstract»

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  • Multiple coupled circuit modeling of induction machines

    Publication Year: 1995 , Page(s): 311 - 318
    Cited by:  Papers (88)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (612 KB)  

    A new multiple coupled circuit model is presented for simulation of induction machines with both arbitrary winding layout and/or unbalanced operating conditions. The model is derived by means of winding functions. No symmetry is assumed. The parameters of the model are calculated directly from the geometry and winding layout of the machine. The behavior of an induction machine during starting is simulated using this model. The results are shown to be in good agreement with the solution obtained by a conventional d-q model for symmetric conditions. The new model is then extended to the solution of a wide variety of fault conditions such as broken bars and end rings and open or short circuited motor coils View full abstract»

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  • The value of controls and monitoring for electrical heating tracing

    Publication Year: 1995 , Page(s): 429 - 437
    Cited by:  Papers (4)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (952 KB)  

    In this paper the variety of controls and monitoring methods in use today are explored to develop an understanding of the advanced technologies available. Mechanical, solid-state and microprocessor-based packages are reviewed with particular attention given to multi-circuit centralized systems. As the costs of many systems continue to rise, questions regarding the value from the users' perspectives are also explored View full abstract»

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  • A new design concept of permanent magnet machine for flux weakening operation

    Publication Year: 1995 , Page(s): 373 - 378
    Cited by:  Papers (38)  |  Patents (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (572 KB)  

    In this paper, a new design concept of a PM machine for flux weakening operation is proposed. The feasibility of strong flux weakening capability without permanently demagnetizing the permanent magnet is investigated. Results from the finite element analysis on the proposed PM machine structure are presented to verify the new design concept View full abstract»

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  • Short circuit behavior of IGBTs correlated to the intrinsic device structure and on the application circuit

    Publication Year: 1995 , Page(s): 234 - 239
    Cited by:  Papers (14)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (424 KB)  

    Problems associated with the short circuit tolerance of power control circuits can be solved successfully using IGBTs as power switches even when the intrinsic short circuit performance of these devices is modest. The protection circuit of an IGBT with modest short circuit capability is more critical then the protection circuit of a rugged IGBT. On the other hand, IGBTs with the best short circuit performance have the higher operating losses due to their higher saturation voltage. This note demonstrates how the IGBTs and the protection circuit were optimized to get the best trade-off between efficiency, ruggedness, and reliability of the application View full abstract»

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  • In-service evaluation of motor and generator stator windings using partial discharge tests

    Publication Year: 1995 , Page(s): 299 - 303
    Cited by:  Papers (13)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (544 KB)  

    Partial discharges (corona) are a symptom of most types of deterioration of motor and generator stator windings rated 4 kV and above. Experience indicates that partial discharges occur years before failure. This leaves sufficient time to plan corrective maintenance to avoid the in-service failure of the motor or generator. This paper describes a new type of partial discharge test which can be performed by plant personnel during normal operation of the machine, thus enabling all users of large machines to plan maintenance. The key requirement of the new test is to remove all the interference caused by other sparking and discharging sources in a plant. Such noise has lead to false indications of stator winding deterioration in the past. The new test uses either high-voltage capacitive sensors, high-frequency current transformers, or 1000 MHz electromagnetic couplers to detect the discharge signals. These signals are processed on a pulse-by-pulse basis by a specialized electronic instrument to remove noise and the remaining partial discharges are then categorized according to number, magnitude, and phase position. The test has been implemented on over 100 machines, and the results appear promising View full abstract»

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  • Cement kiln dust (CKD) methods for reduction and control

    Publication Year: 1995 , Page(s): 407 - 412
    Cited by:  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (480 KB)  

    Cement kiln dust (CKD) is a waste product generated during the manufacture of Portland Cement. Volatile compound buildup in cement kilns results in the need to purge the system which stabilizes the process or brings the product quality within specifications. This paper outlines a stepwise approach for reducing CKD generation. The present cost penalties for generating CKD along with potential future liabilities of stored dust should make CKD reduction a main priority. Many cement plants have gone through similar investigations in the past, however most could benefit from re-examining their present dust wasting situation and applying new testing programs now available. This investigative process can be relatively simple and should be a high priority on any cement plant's agenda. Following a stepwise, organized approach can often result in large reductions in dust wasting. Today's technology allows the improved sampling and rapid chemical analysis needed for each plant to establish and follow a volatile management program resulting in the reduction of CKD generation View full abstract»

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  • Design of a new axially-laminated interior permanent magnet motor

    Publication Year: 1995 , Page(s): 358 - 367
    Cited by:  Papers (39)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (964 KB)  

    The design of a new type of axially-laminated interior permanent magnet motor drive showing an extremely wide constant-power speed range which exceeds 7.5:1 is described. The effect on the field-weakening performance of the number of poles, the pole-piece material, the rotor bolt holes, the airgap size, the rotor insulation ratio, and the magnet type are analyzed using analytical and finite-element techniques. A 7.5-kW synchronous reluctance and a 7.5-kW interior permanent magnet axially-laminated rotor were built for a commercial induction motor stator and experimental low-speed and field-weakening results are presented View full abstract»

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  • Transducerless position and velocity estimation in induction and salient AC machines

    Publication Year: 1995 , Page(s): 240 - 247
    Cited by:  Papers (349)  |  Patents (11)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (680 KB)  

    This paper presents a viable transducerless rotor position and velocity estimation scheme for PWM inverter driven induction, synchronous, and reluctance machines with the capability of providing robust and accurate dynamic estimation independent of operating point, including zero and very high speeds, light and heavy loading. The injection of a balanced three-phase high frequency signal (500 to 2 kHz) generated by the inverter, followed by appropriate signal demodulation and processing combined with a closed-loop observer, enable the tracking of rotor magnetic saliencies from the machine terminals. Although rotor magnetic saliency is inherent within reluctance machines, and most synchronous machines, saliency in the induction machine is introduced via a modulation of the rotor slot leakage with minimal detrimental effects on the machine performance. Experimental verification for the induction machine is included View full abstract»

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  • Basics and advances in battery systems

    Publication Year: 1995 , Page(s): 419 - 428
    Cited by:  Papers (9)  |  Patents (5)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (924 KB)  

    One of the most common components in both the utility and industrial/commercial power system is the stationary battery. In many cases, the original design is marginal or inadequate; the maintenance and testing is practically nonexistent; but the system is called upon during emergency conditions and is expected to perform flawlessly. This paper begins with basic battery theory starting with the electrochemical cell. A working knowledge of the battery cell is important to understand typical problems such as hydrogen production, sulfating, and battery charging. The paper then discusses some of the common batteries and battery chargers. While this paper concentrates primarily on the lead acid type of battery, the theory can be utilized on other types such as the nickel-cadmium. Reference is made to industry standards and codes which are used for the design, installation, and maintenance of battery systems. Along with these standards is a discussion of the design considerations, maintenance and testing, and, finally, some advanced battery system topics such as individual battery cell voltage equalizers and battery pulsing units. The goal of this paper is to provide the reader with a basic working understanding of a battery system. Only with that knowledge can a person be expected to design and/or properly maintain a battery system which may be called upon during an emergency to minimize the effects of a normal power outage, to minimize personnel hazards and to reduce property damage 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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Editor-in-Chief
Carlton E. Speck