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Industry Applications Society Annual Meeting, 1991., Conference Record of the 1991 IEEE

Date Sept. 28 1991-Oct. 4 1991

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Displaying Results 1 - 25 of 293
  • A model to predict current distributions in heavy current parallel conductor configurations

    Page(s): 1098 - 1103 vol.2
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    The authors present a model for predicting the current distribution in high-current cables consisting of relatively widely spaced parallel conductors. These cables are typically used in electric glass melters to interconnect the power transformers and the melter secondary bus installations. Due to mutual inductive coupling between the conductors, electromagnetic forces will cause uneven current distribution. The proposed model has been developed to account for these forces in specified parallel conductor configurations. The model also takes into account the skin effect impact on the individual conductor resistances and self-inductances. The model is coded in a simple computer program which can be used to predict current distributions in electric glass melters and similar heavy current applications. Results obtained using the proposed model for a Scott-T transformer with a variety of multiconductor cable configurations are presented for demonstration purposes.<> View full abstract»

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  • Batch charger control options and effects

    Page(s): 1104 - 1108 vol.2
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    The controls of batch chargers can have a direct effect on the efficiency of the melting process as well as the environmental conditions associated with the process. The authors outline control options and describe the effects. Emphasis is placed on the blanket-type batch/cullet feeder, one of the mainstays of the large volume glass producer. The control options which are incorporated include positive materials displacement, i.e. metered discharge; charger pan speed variation; charger pan stroke variation; and charger pan angle variation.<> View full abstract»

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  • A computer vision system for the characterization and classification of flames in glass furnaces

    Page(s): 1109 - 1117 vol.2
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    It is pointed out the characterization and classification of certain phenomena that occur inside glass furnaces is of the utmost importance for the design of efficient and energy-saving control strategies. The authors describe a computer vision system dealing with both flame analysis and classification problems. The system was first tested in a laboratory environment where different operating conditions were created through the variation of the burner geometry, the number of active burners, and the rate of fuel used. Two classifiers, one based on a Bayesian formalism and the other on neural networks, were designed and tuned in a laboratory environment. In a second phase, images from an industrial furnace were acquired, several flame classes were defined, and the classifiers were tested. The results obtained by both the Bayesian and the neural network classifiers are quite encouraging and the success rates are similar for both of them.<> View full abstract»

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  • Survey of adjustable frequency technology - 1991

    Page(s): 1118 - 1126 vol.2
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    The state-of-the-art in 600 V adjustable frequency drive technology is reviewed for the end user from the perspective of the equipment designer. Certain specific qualities of the drives are related to their effect on performance, cost, reliability, and the environment. Particular attention is given to the power circuitry and power switches, the invertor control function, digital drive logic, the human interface, diagnostics, serial communications, envelope control, provisions for regeneration, line current effects, and application of motors.<> View full abstract»

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  • Mill motors for adjustable speed AC drives

    Page(s): 1127 - 1133 vol.2
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    AC adjustable speed drives are being considered for many rolling mill applications. The author describes AC motor characteristics, and how they relate to adjustable speed mill drives. Included is a review of AC motor theory highlighting distinctions between induction and synchronous machines along with comparisons to DC motor performance. Constant power speed range performance and limitations, damper winding requirements, and the selection of motor variables such as terminal voltage and frequency are discussed.<> View full abstract»

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  • AC-cycloconverter drives for cold and hot rolling mill applications

    Page(s): 1134 - 1140 vol.2
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    It is pointed out that there are several possibilities to realize an AC variable speed drive with cycloconverters. The motor can be an asynchronous or a synchronous type and the cycloconverter can be operated with or without circulating current. The author presents the characteristics of the different solutions and compares their performance in rolling mill main drive applications. The comparison is based on real applications in hot and cold rolling mills and on additional simulations. It is shown that the decision for the optimal configurations depends on the individual requirements of the technological process. For example, the required peak load and constant power range may have a remarkable influence on the design of the drive system, depending on the motor type. A short report about practical applications in hot and cold, reversing and finishing rolling mills is given.<> View full abstract»

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  • Application strategies for AC rolling mill drives

    Page(s): 1141 - 1147 vol.2
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    It is demonstrated that by properly selecting a suitable cycloconverter-fed AC drive system for a prospective rolling mill one can expect not only an excellent performance and responsive controls, but also a minimum consumption of incoming power and reduction of running energy cost. A noncirculating current cycloconverter drive is the most suitable for large-scale and low-speed drives, such as hot reversing mill main stands, while a circulating current cycloconverter drive is best suited for a tandem cold mill, which requires a high capability of speed control. The system can drive the mill at a quick speed response of omega /sub c/=60 rad/s in a wide speed range. This control performance increases the possibilities for improvements in the gage thickness accuracy control and in the production yield rate.<> View full abstract»

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  • On-line measuring device of hot steel shapes

    Page(s): 1148 - 1152 vol.2
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    In order to improve productivity of the Large Shape Mill at Kashima Steel Works, an online profile measuring system of hot steel shape with a laser has been developed. The system can automatically measure four shapes which are produced in 288 sizes in total. The system can measure the shape which is on the rolling table. The temperature of the measured shape is approximately 800 degrees C. Five methods are adopted to greatly improve accuracy. After adopting the automatic measuring system the productivity of the Large Shape Mill has increased 1.5% compared with manual measurements.<> View full abstract»

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  • Controls and drives of coil feeder for hot formers

    Page(s): 1153 - 1156 vol.2
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    A coil feeder has been developed which permits the use of coiled bar stocks for hot-forging facilities to manufacture nuts and other parts of automobiles. This coil-feeder for hot-formers was developed with a high-accuracy frequency control system. It consists of an uncoiler, a straightener, and a pair of pinch rollers. This system improves the product yield rate dramatically compared with conventional feeders while maintaining high product quality. The control equipment is described, and test results are presented.<> View full abstract»

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  • Comparison VSI and PWM drives in an aluminum rolling mill ingot preheating application

    Page(s): 1157 - 1163 vol.2
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    Rising concern about work environments and power system efficiency has prompted careful evaluation of adjustable speed drive applications. A case study is presented from data collected in a large industrial facility. A brief description of the process precedes comparisons of pulsewidth modulated (PWM) variable frequency drives to six-step voltage source (VSI) variable frequency drives on a variable torque load. The two types of drive are installed in similar systems. Motor acoustical noise and harmonic current injection into the power distribution system are examined. Test methods and results are discussed.<> View full abstract»

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  • Adjustable speed AC drive for fan vibration control

    Page(s): 1164 - 1167 vol.2
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    Vibration was once a damaging problem to the fans for the coke emission control system at the Ashland, Kentucky plant of Armco Inc. After evaluation of several ways to correct the problem, Armco elected to install an adjustable speed AC drive system which used the existing motor to control the air flow and to remove the damper, which was the cause of the flow instability and the resultant vibration. The adjustable speed drive system not only corrected the vibration problem, but also increased the operating efficiency of the system and reduced the annual power costs by several thousand dollars in the first year. The authors present the problem, the alternate corrective actions which were evaluated, the system performance after the retrofit, and the design considerations for the adjustable speed drive system. They also address current fan application considerations at Armco and the state-of-the-art technology and hardware for adjustable speed AC drive systems.<> View full abstract»

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  • Control and scale model simulation of sensor-guided LHD mining machines

    Page(s): 1168 - 1174 vol.2
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    Work has been underway on the development of autonomous (tele-managed) LHD (load, haul, and dump) mining machines. Previous work has shown that ultrasonic sensors exhibit several characteristics which make them a reasonable choice for sensor-based navigation in underground mining operations. The authors discuss recent work done to develop control algorithms for use with these sensors, experiments with a scale model of an LHD miner to verity the ultrasonic-based control and modeling methods, and approaches to developing real-time task level control models. Experimental testing of a scale-model system indicates that acceptable behavior can be achieved if the speed is kept low and a deadband is introduced into the control algorithm. Transition logic appears to be a useful tool for describing the control system at a task level.<> View full abstract»

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  • Intelligent waveform analysis for ultrasonic ranging in a cluttered environment

    Page(s): 1175 - 1181 vol.2
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    It is shown that, in a limited domain, ultrasonic rangers can be used with model-based reasoning to identify one or two objects represented in the return signal. It is also shown that characteristics that are useful in helping discriminate include average amplitude times distance, standard deviation of the amplitude as a percentage of the maximum amplitude, and characteristics of the echo signal such as maximum echo amplitude times the square of the distance. It was found many of the characteristics (such as maximum amplitude) were not helpful in discriminating between objects at various distances. It was found that a list of line features describing perimeter shape was not useful when objects were considered at various distances. The results obtained are pertinent to the Autonomous Land Vehicle (ALV).<> View full abstract»

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  • A radar coal thickness sensor

    Page(s): 1182 - 1191 vol.2
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    A radar coal thickness sensor is being developed by the Bureau of Mines to measure both the dielectric constant and thickness of a coal seam as part of a sensor array supporting a computer-assisted coal mining machine. The noncontacting stepped-CW (continuous wave) radar sensor measures the complex reflection coefficient of the coal/shale interface to resolve the coal thickness to subwavelength accuracies. The technique uses a monostatic antenna configuration. Transfer function errors are identified by using spatial modulation created by antenna motion. Synthetic range gating is used for clutter rejection. Finally, polarimetric scattering matrix techniques are used to calculate the dielectric constant and thickness of the multilayered coal/shale media. Data taken both in the laboratory and in an underground mine, in the 0.6 to 1.4 GHz range, with a network analyzer and dipole antenna, have validated the technique. Accurate in-situ measurements were made of a coal seam 6 in (15.2 cm) thick with a dielectric constant of 4.<> View full abstract»

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  • Research into a sensor-based diagnostic maintenance expert system for the hydraulics of a continuous mining machine

    Page(s): 1192 - 1199 vol.2
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    The US Bureau of Mines is completing development of a diagnostic maintenance system as part of its investigation into using expert system techniques to diagnose and predict hydraulic problems on a continuous mining machine. The Bureau has developed an expert knowledge base to diagnose hydraulic problems on a Joy 16CM continuous mining machine. This diagnostic system is interfaced to machine-based sensors which monitor various hydraulic system parameters, such as pressures, flows, temperatures, fluid level, and ferrous debris present in the oil. The status of these parameters is updated periodically and transmitted via a distributed interface to the diagnostic knowledge base. All diagnostic decisions are made based upon the available sensor information. The testing and evaluation plans for this system on the 16CM are outlined.<> View full abstract»

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  • The effective control of a deep hole diamond drill

    Page(s): 1200 - 1205 vol.2
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    In the gold exploration drilling industry, time-dependent costs have become the major proportion of the total costs per meter drilled. Therefore, bit performance in terms of penetration rate and life has become extremely important. The author describes the application of a control system for controlling the parameters which determine the performance of a deep-hole diamond drill. The important parameters influencing drill bit performance are discussed. The philosophy behind the design of the control system and a description of the different control functions are given. A rough analysis done on an assumed model indicated that stable, well-damped, closed-loop control could be maintained over the wide range of system dynamics which were expected to be encountered.<> View full abstract»

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  • Learning design rules and concepts for examples-a case study to design an electric power substation design

    Page(s): 1206 - 1215 vol.2
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    Some principles of machine learning and some links with knowledge base system are described. A domain-independent inductive learning system (ILS) has been developed and implemented. ILS can be attached to any expert system, and will work as a knowledge acquisition module for the expert system. This gives the expert system the ability to update and expand its knowledge base according to the circumstances. ILS is a logic-based, data-driven learning system, focusing on the problem of learning structural descriptions. ILS is tailored to design electrical system components. In the present work, ILS is used for specifying the major components of an electrical substation. The learning system will learn design rules and concepts from positive and negative examples in the form of existing substations. This system will take examples and generate rules and concepts for specifying the major components of an electric substation.<> View full abstract»

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  • An expert system for specifying the major substation components: machine learning approach

    Page(s): 1216 - 1222 vol.2
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    A learnable expert system for substations (LESS) has been developed that will learn design rules of the substations from examples. The resulting rules and concepts reflect the philosophy of design embedded in the provided examples. Thus, the substation design will be consistent with the design of the other substations owned and operated by the company if the examples consist of descriptions of their existing substations. LESS is combined with two learning modules to acquire the design knowledge required for specifying the major components and the layout of an electric substation. LESS has the capability of accepting rules dictated by laws, codes or standards, as well as formulating rules based on design practice which are learned from positive examples. It can also avoid certain problematic situations in past designs by observing negative examples. LESS has graphical capability and will produce a plan view of the substation.<> View full abstract»

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  • Characteristics of dimension restrained dry-type transformers

    Page(s): 1223 - 1227 vol.2
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    It is pointed out that dry type transformers are often restrained in one or more directions to permit their use in confined areas. This is particularly true in underground coal mines where the height is limited by the seam thickness. The historical increase in machinery horsepower fuels the escalation of transformer capacity required within these confined areas. The author investigates how a restrained dimension affects the operating characteristics of a transformer. Each characteristic is examined from a relational standpoint, with changes in the horizontal and vertical dimensions. The derived conclusions are then compared to empirical data obtained from families of commercial designs. The families of commercial designs show the critical nature of using volts/turn for controlling the total transformer volume. The actual volts/turn used must also satisfy the requirements of ratio and impedance. Each restraint placed upon the volts/turn, such as additional windings, can have an adverse effect upon the overall volume.<> View full abstract»

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  • Protection for low and medium voltage AC trailing cables

    Page(s): 1228 - 1235 vol.2
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    In 1981 a mining equipment manufacturer approached the Mine Safety and Health Administration with a combination fuse contactor device requesting that it be permitted as a means of protection for low and medium voltage, three phase AC trailing cables. The concept behind the design of the vacuum contactor-fuse device was to use a vacuum contactor to provide protection to a specific current level during abnormal circuit conditions. If fault currents exceeded this level, a current limiting fuse would be used to interrupt the current before the vacuum contractor could open. The authors describe the tests and criteria developed to ensure that the device provided no less protection than a molded case circuit breaker. Details of the laboratory tests are presented. The vacuum circuit breaker meets 30 CFR 75900, 75902 and 75601 in that it provides suitable protection against undervoltage, grounded phase, overcurrent, and short circuits.<> View full abstract»

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  • A comparison of shielded versus non-shielded trailing cables for reeled applications

    Page(s): 1236 - 1242 vol.2
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    Differences in cable life, the modes of failure, the ease of repair, and other pertinent comparisons are discussed for shielded versus nonshielded cables for underground mines. It is shown that type G-GC cables are longer-lasting than type SHD cables under severe reeling stresses, due primarily to the low compression resistance but also the low shear resistance of the cotton/copper braid shield. Breakage of individual wires leaves the sharp ends free to penetrate the insulation and initiate cable failure. While there is a good margin of safety built into recommendations, proper tension and the associated sidewall loading ultimately determine cable life for shielded versus unshielded cables for underground mines.<> View full abstract»

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  • Fiber optics for atmospheric mine monitoring

    Page(s): 1243 - 1249 vol.2
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    The authors describe work done by the US Bureau of Mines to address methane, carbon monoxide, and distributed temperature monitoring. A review is made of the potential and problems of using fiber optics for mine monitoring systems. Methane detection is based on differential absorption of infrared light. A methane monitor that can detect concentrations as low as 0.2% as far away as 2 km via fiber-optic cable is described. The upper range is 100% volume methane. Since the system requires no electrical power within the mines, it is intrinsically safe. A carbon monoxide monitoring system that combines a low-powdered electrochemical cell with fiber-optic telemetry is described. Testing has shown the system can operate maintenance-free for several months. Finally, a distributed fiber-optic temperature monitoring system is being investigated for possible application in mine fire detection. The sensor employs optical time domain reflectometry techniques that allow the entire length of fiber (up to 2 km) to function as a distributed temperature sensor.<> View full abstract»

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  • E FATALS-a computer program for the analysis of electrocutions in the mining industry

    Page(s): 1250 - 1253 vol.2
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    The authors describe an application program, known as E FATALS, which was developed to facilitate analysis of the Mine Safety and Health Administration database of electrical fatalities in mining. E FATALS in a menu-driven and user-friendly program than can be executed on DOS-based personal computers. The advantages of using E FATALS for performing safety analyses are stated, and some examples of such usage are given.<> View full abstract»

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  • An investigation of the ignition hazards associated with various materials in the breakflash apparatus

    Page(s): 1254 - 1262 vol.2
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    The US Bureau of Mines Pittsburgh Research Center has completed an investigation of the degree to which various disk materials affect the probability of igniting a methane-air atmosphere using the breakflash machine. Data were generated for estimating currents (resistor or inductor circuits) and voltages (capacitor circuits) associated with a particular ignition level. Further analysis of these data was used to assign hazard levels for each material, with cadmium used as a reference material. From this, a safety factor was associated with each material. Presently, there are no construction requirements with regard to materials of construction. The worst case is always assumed (i.e., cadmium). Laboratory test results confirmed cadmium as the worst-case material among those tested for resistor and inductor circuits but not for capacitor circuits. In fact, aluminum testing illustrated lower ignition voltages than cadmium at 107 and 1310 mu F. For capacitor circuits, little, if any, safety was gained by using certain materials other than cadmium.<> View full abstract»

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  • Contactless power delivery system for mining applications

    Page(s): 1263 - 1269 vol.2
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    The authors present the application of a power delivery system design unifying power electronics and a coaxial-winding transformer for devices that require contactless connection and/or relative motion while delivering large amounts of power. The transformer's unique characteristics and how they might be used to advantage in combination with power electronics are emphasized. Applications which have near-term realizability are flexible power distribution, material handling, autonomous electric vehicles, and battery opportunity recharge. Test results on a scale prototype are presented to verify the concepts.<> View full abstract»

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