The Experts below are selected from a list of 144 Experts worldwide ranked by ideXlab platform
Athanasions N. Safacas - One of the best experts on this subject based on the ideXlab platform.
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Dynamic and vibration analysis of a multimotor DC drive system with elastic shafts driving a tissue paper machine
IEEE Transactions on Industrial Electronics, 2007Co-Authors: Costas A. Michael, Athanasions N. SafacasAbstract:In this paper, the influence of the stiffness and damping of real elastic shafts on the behavior of a multidrive system driving a tissue paper machine is investigated. The drive system consists of four dc motors, where two of them drive the Yankee Drying Cylinder and the other two drive the presses section. Six-pulse thyristor bridge power converters that are connected to the same power transformer supply the motors. The inertias of the motors and the driven machines, in conjunction with the shaft stiffness, form mechanical resonators. Thus, resonance phenomena may occur, which may lead to undesirable results. This particular case results to two three-mass and one five-mass systems. This paper presents an analysis of the resonance frequencies of two sections of the machine during startup and machine production, considering the shaft stiffness (shaft diameter, length, and thickness). The elastic shafts eliminate the ripple of the motor electromagnetic torque, which is transferred to the driven machine. The behavior of elastic shafts with different stiffness in the transmission system is studied. Moreover, the steady state and dynamic behavior of the system considering the influence of the elastic shafts and vibration analysis were investigated using simulation. A model algorithm for system simulation was developed using the MATLAB/SIMULINK software. Characteristic simulation results are presented and are expressed in terms of speed and torque response. Considering the resonance frequency analysis and simulation results, mechanical design guidelines can be given for the most significant drive components in order to avoid torsional oscillation resonance phenomena and minimize torsional oscillations of the drive system.
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Behavior of a drive system consisting of two DC motors with elastic shafts driving the Yankee Drying Cylinder of a tissue paper machine
The 4th International Power Electronics and Motion Control Conference 2004. IPEMC 2004., 2004Co-Authors: C. Michael, Athanasions N. SafacasAbstract:In this paper the behavior of elastic shafts in a drive system consisting of two D.C. motors driving the Yankee Drying Cylinder of a tissue paper machine is investigated. The motors are fed by two 6-pulse thyristor converters connected to the same power transformer. The master motor has a tachogenerator to measure the speed of the system. Control logic is proposed to control the torque of the two DC motors. The control can be achieved in such a way that the two motors contribute the same amount to the total load in the case that the DC motors are identical, or contribute partly to the total load and proportionally to their nominal torques in the case that the two motors are not identical. The adjustment of the acceleration time and the parameters of the PI controllers is investigated in order to keep the maximum armature current below the limit of maximum permissible current and to achieve an optimum speed response of the system. The use of different elastic shafts (different stiffness) connected between DC motors and gearbox is investigated. The shaft of the Yankee Drying Cylinder is so thick that it can be considered as a stiff shaft without elasticity. The analysis of the system is realized using the SIMULINK software. Characteristic simulation results are presented.
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Analysis of a drive system consisting of two DC motors driving the Yankee Drying Cylinder of a tissue paper machine
2003 IEEE International Symposium on Industrial Electronics ( Cat. No.03TH8692), 2003Co-Authors: C. Michael, Athanasions N. SafacasAbstract:In this paper the analysis of a drive system consisting of two D.C. motors driving the Yankee Drying Cylinder of a tissue paper machine is presented. Two 6-pulse thyristor converters connected to the same power transformer feed the motors. The motor, which has on it the tachogenerator to measure the speed, is the master motor and the other motor is the helper. Control logic is proposed to control the torque of the two DC motors. The control can be achieved in such a way that the two motors contribute equally to the total load when the DC motors are identical, or contribute partly to the total load and proportionally to their nominal torques, if the two motors are not identical. The adjustment of the acceleration time and the parameters of the controllers are investigated, in order to keep the armature current below the maximum permissible current as well as to achieve an optimum speed response of the system. The commissioning time can be reduced significantly, adjusting the acceleration time and the controllers' parameters, and so the distress of the system's electrical and mechanical parts can be avoided. Any possible damages caused by the rapid or unstable operation of the electrical and mechanical parts during commissioning and tests also can be avoided. A fine adjustment of the real system in less time during commissioning can be obtained after the determination of the acceleration time and controllers' parameters. The analysis of the system is realized using the SIMULINK software. Typical simulation results are presented.
Costas A. Michael - One of the best experts on this subject based on the ideXlab platform.
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Dynamic and vibration analysis of a multimotor DC drive system with elastic shafts driving a tissue paper machine
IEEE Transactions on Industrial Electronics, 2007Co-Authors: Costas A. Michael, Athanasions N. SafacasAbstract:In this paper, the influence of the stiffness and damping of real elastic shafts on the behavior of a multidrive system driving a tissue paper machine is investigated. The drive system consists of four dc motors, where two of them drive the Yankee Drying Cylinder and the other two drive the presses section. Six-pulse thyristor bridge power converters that are connected to the same power transformer supply the motors. The inertias of the motors and the driven machines, in conjunction with the shaft stiffness, form mechanical resonators. Thus, resonance phenomena may occur, which may lead to undesirable results. This particular case results to two three-mass and one five-mass systems. This paper presents an analysis of the resonance frequencies of two sections of the machine during startup and machine production, considering the shaft stiffness (shaft diameter, length, and thickness). The elastic shafts eliminate the ripple of the motor electromagnetic torque, which is transferred to the driven machine. The behavior of elastic shafts with different stiffness in the transmission system is studied. Moreover, the steady state and dynamic behavior of the system considering the influence of the elastic shafts and vibration analysis were investigated using simulation. A model algorithm for system simulation was developed using the MATLAB/SIMULINK software. Characteristic simulation results are presented and are expressed in terms of speed and torque response. Considering the resonance frequency analysis and simulation results, mechanical design guidelines can be given for the most significant drive components in order to avoid torsional oscillation resonance phenomena and minimize torsional oscillations of the drive system.
C. Michael - One of the best experts on this subject based on the ideXlab platform.
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Behavior of a drive system consisting of two DC motors with elastic shafts driving the Yankee Drying Cylinder of a tissue paper machine
The 4th International Power Electronics and Motion Control Conference 2004. IPEMC 2004., 2004Co-Authors: C. Michael, Athanasions N. SafacasAbstract:In this paper the behavior of elastic shafts in a drive system consisting of two D.C. motors driving the Yankee Drying Cylinder of a tissue paper machine is investigated. The motors are fed by two 6-pulse thyristor converters connected to the same power transformer. The master motor has a tachogenerator to measure the speed of the system. Control logic is proposed to control the torque of the two DC motors. The control can be achieved in such a way that the two motors contribute the same amount to the total load in the case that the DC motors are identical, or contribute partly to the total load and proportionally to their nominal torques in the case that the two motors are not identical. The adjustment of the acceleration time and the parameters of the PI controllers is investigated in order to keep the maximum armature current below the limit of maximum permissible current and to achieve an optimum speed response of the system. The use of different elastic shafts (different stiffness) connected between DC motors and gearbox is investigated. The shaft of the Yankee Drying Cylinder is so thick that it can be considered as a stiff shaft without elasticity. The analysis of the system is realized using the SIMULINK software. Characteristic simulation results are presented.
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Analysis of a drive system consisting of two DC motors driving the Yankee Drying Cylinder of a tissue paper machine
2003 IEEE International Symposium on Industrial Electronics ( Cat. No.03TH8692), 2003Co-Authors: C. Michael, Athanasions N. SafacasAbstract:In this paper the analysis of a drive system consisting of two D.C. motors driving the Yankee Drying Cylinder of a tissue paper machine is presented. Two 6-pulse thyristor converters connected to the same power transformer feed the motors. The motor, which has on it the tachogenerator to measure the speed, is the master motor and the other motor is the helper. Control logic is proposed to control the torque of the two DC motors. The control can be achieved in such a way that the two motors contribute equally to the total load when the DC motors are identical, or contribute partly to the total load and proportionally to their nominal torques, if the two motors are not identical. The adjustment of the acceleration time and the parameters of the controllers are investigated, in order to keep the armature current below the maximum permissible current as well as to achieve an optimum speed response of the system. The commissioning time can be reduced significantly, adjusting the acceleration time and the controllers' parameters, and so the distress of the system's electrical and mechanical parts can be avoided. Any possible damages caused by the rapid or unstable operation of the electrical and mechanical parts during commissioning and tests also can be avoided. A fine adjustment of the real system in less time during commissioning can be obtained after the determination of the acceleration time and controllers' parameters. The analysis of the system is realized using the SIMULINK software. Typical simulation results are presented.
Torbjorn Wahlstrom - One of the best experts on this subject based on the ideXlab platform.
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Influence of shrinkage and stretch during Drying on paper properties
2020Co-Authors: Torbjorn WahlstromAbstract:When Drying, paper strives to shrink due to the shrinkage of the individual paper fibres. Laboratory results show that a reduction of shrinkage or an imposed stretch leads to a large increase in tensile stiffness and a large decrease in strain at break - i.e. the extent to which it is possible to stretch the paper before it breaks. In a Cylinder Drying section, the water in the web is repeatedly heated on the Drying Cylinder and evaporated in the free draw. To evaluate influence of the Drying process on paper properties, these subprocesses, or Drying phases, have to be studied separately. The effect of Drying Cylinder and VacRoll is investigated in pilot trials. Both the fabric tension and the vacuum in the VacRoll reduces the shrinkage of the paper. The laboratory results were fed into a numerical simulation of the conditions in the free draw. If the web width is increased or the length of the free draw is reduced, the mean shrinkage of the paper web is reduced. However, the difference in shrinkage between the middle and the edge of the web is increased.
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Influence of shrinkage and stretch during Drying on paper properties
1999Co-Authors: Torbjorn WahlstromAbstract:A Drying paper strives to shrink due to the shrinkage of the individual paper fibres. Laboratory results show that a reduction of the shrinkage or an imposed stretch leads to a large increase in tensile stiffness and a large decrease in strain at break. In c Cylinder Drying section the water in the web is repeatedly heated on the Drying Cylinder and evaporated in the free draw. To evaluate the Drying process regarding influence on paper properties these sub-processes, or Drying phases, have to be studied separately. The effect of the conditions on the Drying Cylinder and on the VacRoll is investigated in pilot trails. Both the fabric tension on the Drying Cylinder and on the VacRoll reduces the shrinkage of the paper. The laboratory results are used as input to a numerical simulation of the conditions in the free draw. If the web width is increased or the length of the free draw is reduced the mean shrinkage of the paper web is reduced . However, the difference in shrinkage between the middle and the edge of the web is increased.
Wei Wang - One of the best experts on this subject based on the ideXlab platform.
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The Temperature-Online-Measuring and Energy-Saving System for Drying Cylinder Based on Network Communication
Advanced Materials Research, 2013Co-Authors: Chong Qian, Rong Rong Wang, Wei WangAbstract:During the process of Drying fabrics by Drying Cylinder dryer, the over-Drying of fabrics leads to a waste of energy. A temperature-online-measuring and energy-saving system for Drying Cylinder dryer based on network communication was designed in the study. The temperature-measuring and steam-controlling part of the system set in the Cylinder dryer communicates with the remote monitoring part using the W5100 network chip through Ethernet which helps to achieve a high-speed and long-distance communication between the two parts. The remote monitoring part of the system is based on Delphi. The real-time temperature of fabrics in each Drying Cylinder can be displayed on the screen of the remote computer, and the steam supply of Drying Cylinders can be manually or automatically adjusted according to the mutations of temperature of fabrics by system administrators or the remote computer. The application of this system helps to avoid the The evaporation of water due to over-Drying by 5.3%-6.6% and result in a reduction of the waste of energy by about 10%.
