This document discusses active magnetic bearings (AMBs). It provides background on AMBs, explaining that they support rotating machinery without physical contact using electromagnetic forces controlled by sensors and electronics. The document then describes the basic components and working principles of AMB systems, including electromagnets, position sensors, and control systems that use feedback to maintain the rotor's position. It explains that AMBs offer benefits over traditional bearings like reduced friction, vibration, and maintenance needs. However, it notes that AMB systems are more complex and expensive to implement initially.
A PROJECT REPORT SIM & SPEED CONTROL OF INDUCTIO DRIVEPawan Kumar
The document discusses speed control methods for three-phase induction motors. It analyzes the transients during starting of an induction motor with different machine parameters. It then examines various speed control methods including variable rotor resistance, variable stator voltage, and constant V/f control. Simulation results are presented to show the torque-speed characteristics for each method. Vector control is also introduced, which allows independent control of torque and flux.
Active magnetic bearings used as exciters for rolling element bearing outer r...ISA Interchange
The active health monitoring of rotordynamic systems in the presence of bearing outer race defect is considered in this paper. The shaft is assumed to be supported by conventional mechanical bearings and an active magnetic bearing (AMB) is used in the mid of the shaft location as an exciter to apply electromagnetic force to the system. We investigate a nonlinear bearing-pedestal system model with the outer race defect under the electromagnetic force. The nonlinear differential equations are integrated using the fourth-order Runge–Kutta algorithm. The simulation and experimental results show that the characteristic signal of outer race incipient defect is significantly amplified under the electromagnetic force through the AMBs, which is helpful to improve the diagnosis accuracy of rolling element bearing's incipient outer race defect.
active magnetic beraing is a mechatronic device which support
rotating parts to decrease friction ,amb have less vibration
it is a good topic to take as a seminar topic . there is a 12 slide to take class about 20 minutes
Electrical drive unit 1 as per IP university_EEEamrutapattnaik2
it is the complete Electrical Drive syllabus of the unit1. i 've tried a lot to merge everything in one PPT.it might be helpful for final year students.
i am also thankful to slideshare as I also collected all data and notes from this site too.
kindly share your suggestions for the improvement
Active magnetic bearings support a rotating shaft without physical contact by using electrically controlled magnetic forces to levitate the rotor. They involve mechanical, electrical, control, and computer engineering. An active magnetic bearing uses sensors to measure the rotor's position, a controller derives a control signal, amplifiers generate a control current to produce magnetic forces that maintain the hovering position based on control laws ensuring stability, stiffness, and damping. Benefits include lubrication-free operation, cleanliness, reliability, high speeds, low vibration and energy use, while disadvantages are high costs, weight, and size. Applications include compressors, turbines, pumps, motors, generators, meters, flywheels, maglev trains, and artificial hearts. Future research
Special bearings in mechanical engineering,MTECH SEMINAR,CAPAGS,BPUT,ROURKELASidharth Adhikari
A SEMINAR WHICH DESCRIBE ABOUT MAGNETICE BEARING AND ITS PHENOMENON AND APPLICATION ,ADVANTAGES,
MTECH SEMINAR ,CENTRE FOR ADVANCE POST GRADUATE STUDIES,BPUT,ROURKELA
IRJET- Speed Control of Three Phase Motor using Fuzzy Logic ControllerIRJET Journal
This document discusses speed control of a three phase induction motor using a fuzzy logic controller. It proposes implementing a fuzzy logic controller based speed control system in MATLAB Simulink. The controller aims to reduce errors between the rotor speed and reference speed as quickly as possible. Simulation results show that the fuzzy logic controller improves the dynamic performance of the induction motor compared to a conventional PI controller. The motor is also able to better withstand load disturbances with less effect on stability. The fuzzy logic control scheme does not require a complex mathematical model of the motor.
This document presents information about magnetic bearings. It discusses the basic components and operation of magnetic bearings, including electromagnets, power amplifiers, controllers, and gap sensors. Magnetic bearings levitate and support rotating machinery without physical contact using magnetic fields, allowing for frictionless and wear-free support. They provide advantages like high speeds, clean operation, and vibration reduction, but also have high costs. Magnetic bearings have applications in machines like compressors, turbines, pumps, motors and generators.
A PROJECT REPORT SIM & SPEED CONTROL OF INDUCTIO DRIVEPawan Kumar
The document discusses speed control methods for three-phase induction motors. It analyzes the transients during starting of an induction motor with different machine parameters. It then examines various speed control methods including variable rotor resistance, variable stator voltage, and constant V/f control. Simulation results are presented to show the torque-speed characteristics for each method. Vector control is also introduced, which allows independent control of torque and flux.
Active magnetic bearings used as exciters for rolling element bearing outer r...ISA Interchange
The active health monitoring of rotordynamic systems in the presence of bearing outer race defect is considered in this paper. The shaft is assumed to be supported by conventional mechanical bearings and an active magnetic bearing (AMB) is used in the mid of the shaft location as an exciter to apply electromagnetic force to the system. We investigate a nonlinear bearing-pedestal system model with the outer race defect under the electromagnetic force. The nonlinear differential equations are integrated using the fourth-order Runge–Kutta algorithm. The simulation and experimental results show that the characteristic signal of outer race incipient defect is significantly amplified under the electromagnetic force through the AMBs, which is helpful to improve the diagnosis accuracy of rolling element bearing's incipient outer race defect.
active magnetic beraing is a mechatronic device which support
rotating parts to decrease friction ,amb have less vibration
it is a good topic to take as a seminar topic . there is a 12 slide to take class about 20 minutes
Electrical drive unit 1 as per IP university_EEEamrutapattnaik2
it is the complete Electrical Drive syllabus of the unit1. i 've tried a lot to merge everything in one PPT.it might be helpful for final year students.
i am also thankful to slideshare as I also collected all data and notes from this site too.
kindly share your suggestions for the improvement
Active magnetic bearings support a rotating shaft without physical contact by using electrically controlled magnetic forces to levitate the rotor. They involve mechanical, electrical, control, and computer engineering. An active magnetic bearing uses sensors to measure the rotor's position, a controller derives a control signal, amplifiers generate a control current to produce magnetic forces that maintain the hovering position based on control laws ensuring stability, stiffness, and damping. Benefits include lubrication-free operation, cleanliness, reliability, high speeds, low vibration and energy use, while disadvantages are high costs, weight, and size. Applications include compressors, turbines, pumps, motors, generators, meters, flywheels, maglev trains, and artificial hearts. Future research
Special bearings in mechanical engineering,MTECH SEMINAR,CAPAGS,BPUT,ROURKELASidharth Adhikari
A SEMINAR WHICH DESCRIBE ABOUT MAGNETICE BEARING AND ITS PHENOMENON AND APPLICATION ,ADVANTAGES,
MTECH SEMINAR ,CENTRE FOR ADVANCE POST GRADUATE STUDIES,BPUT,ROURKELA
IRJET- Speed Control of Three Phase Motor using Fuzzy Logic ControllerIRJET Journal
This document discusses speed control of a three phase induction motor using a fuzzy logic controller. It proposes implementing a fuzzy logic controller based speed control system in MATLAB Simulink. The controller aims to reduce errors between the rotor speed and reference speed as quickly as possible. Simulation results show that the fuzzy logic controller improves the dynamic performance of the induction motor compared to a conventional PI controller. The motor is also able to better withstand load disturbances with less effect on stability. The fuzzy logic control scheme does not require a complex mathematical model of the motor.
This document presents information about magnetic bearings. It discusses the basic components and operation of magnetic bearings, including electromagnets, power amplifiers, controllers, and gap sensors. Magnetic bearings levitate and support rotating machinery without physical contact using magnetic fields, allowing for frictionless and wear-free support. They provide advantages like high speeds, clean operation, and vibration reduction, but also have high costs. Magnetic bearings have applications in machines like compressors, turbines, pumps, motors and generators.
Development of high temperature magnetic bearingsjinfangliu
The document discusses a NASA/Electron Energy Corporation (EEC) Small Business Innovation Research (SBIR) project to develop high temperature permanent magnet biased magnetic bearings and motors. The project aims to utilize EEC's patented SmCo magnets that can operate up to 550°C to develop a technology demonstrator operating at 540°C, including a motor and radial/thrust magnetic bearings. Bench tests of a designed radial bearing show it can produce over 2800N of force at 500°C, around 86% of room temperature performance. A solid model and test apparatus are presented, demonstrating progress toward the project goals.
This document provides an overview of a course on electrical drives and control. It includes 5 units that cover topics such as drive motor characteristics, starting methods, speed control of DC and AC drives using conventional and solid state methods. The introduction defines electric drives and lists their basic elements and functions. It also describes factors that influence the choice of electrical drives such as steady state operation requirements, transient operation requirements, cost considerations, and environmental factors. Heating and cooling curves are also introduced to explain temperature rise in electric machines.
Design and Development of Passive Magnetic BearingIJMER
Passive Magnetic Bearings (PMB) are known for their non-contact and negligible friction
operations but these desirable characteristics of PMB can only be attained if proper designing of bearing
is carried out based on the applied load. To aid to the design of PMB, 3D Coulombian model to estimate
the load carrying capacity of magnetic bearings has been proposed. To exemplify the design procedure,
analyses of various configurations of magnetic bearings have been presented. To economize the magnetic
bearings, usage of easily available square magnets in stator made of aluminium has been proposed.
Finally, a case study has been included to illustrate the design of magnetic bearing.
Speed control of three phase im by vf open and close loop methodeSAT Journals
This document presents a simulation of speed control for a three-phase induction motor using open-loop and closed-loop V/F control methods. In the open-loop method, a PWM inverter drives the motor and the torque is observed to remain constant with varying rotor speed. In the closed-loop method, a PI controller provides feedback to vary the supply frequency to maintain a constant V/F ratio. Simulation results in MATLAB Simulink show that closed-loop control provides superior speed regulation compared to the open-loop method.
1. The document discusses electric drives and their components. Electric drives use electric motors as prime movers and include a power source, power modulator, motor, control unit, and sensing unit.
2. Power modulators can be converters, variable impedance circuits, or switching circuits. Converters provide adjustable voltage/current/frequency to control motor speed and torque. Variable impedance circuits and switching circuits are used to control motor parameters.
3. Electric drives are classified as individual drives, group drives, or multimotor drives depending on how many motors are used to drive different loads. Individual drives use one motor for all loads while group drives use one motor connected to multiple loads through pulleys. Multimotor
Modelling simulation and control of an active suspension systemIAEME Publication
This document discusses the modeling, simulation, and control of an active suspension system in MATLAB/Simulink. It begins by describing conventional passive and semi-active suspension systems, noting their tradeoffs between comfort and control. It then introduces active suspension systems, which can adjust their dynamics in real-time to provide both comfort and control. The document outlines modeling an active suspension system using a quarter car test setup and sensors to measure displacement, acceleration, and velocity. It describes using a linear electromagnetic motor actuated by a power amplifier and controlled via a PID controller to counteract road forces and keep the vehicle stable. The performance of the active suspension is simulated in MATLAB/Simulink and compared to a passive system.
The document provides information on the construction, working principle, and types of transformers. It begins by explaining the necessity of transformers in electrical power systems for stepping up and down voltages. The key points are:
- Transformers transfer power between circuits through electromagnetic induction without changing frequency. They have a primary and secondary winding wound around an iron core.
- Transformers can be used to step up or step down voltages depending on the ratio of turns in the primary and secondary windings. The voltage transformation ratio is equal to the ratio of turns.
- An ideal transformer has zero resistance windings, infinite core permeability, and is lossless. The voltage induced in each winding is directly proportional to its turns and the rate
Rotor Resistance Control of Wound Rotor Induction Generator (WRIG) using PSCA...Anmol Dwivedi
This document describes the modeling and simulation of a variable slip (type 2) wind turbine using a wound rotor induction generator in PSCAD/EMTDC. Key aspects modeled include the turbine aerodynamics, mechanical drive train, induction generator, and rotor resistance control system. Simulation results over different test cases demonstrate the system operating over a wide speed range and optimally extracting power from the wind by varying the rotor resistance of the induction generator.
Selection criteria of motors for various applicationsPrasanth Ravula
The document discusses factors to consider when selecting electric motors for various applications. It describes different types of motors including AC, DC, single phase, and three phase motors. Key selection criteria include the type of power available, size of motor needed based on the load, starting requirements, required speed, bearing type, motor base, and environmental conditions where the motor will operate. The document provides guidelines on matching these criteria to specific application requirements for proper motor selection.
1) Rolling mills require motors that can produce heavy torque at low RPM to roll metal ingots into blooms or slabs. DC motors are well-suited as they can provide high starting torque and wide speed variation.
2) Paper mill drives need variable speed control of multiple rolls. Synchronous motors connected via a Schrage motor allow independent yet coordinated speed control.
3) Marine drives utilize electric propulsion motors like induction or synchronous types to independently power propellers via alternators, providing flexibility and economical operation.
In recent advancements in electric machine and drives, wound rotor motor is extensively used. The merit of using wound rotor induction motor is to control speed/torque characteristics by inserting external resistance. Wound rotor induction motor can be used in the cases such as (a) low inrush current, (b) load requiring high starting torque, (c) lower starting current is required, (d) loads having high inertia, and (e) gradual built up of torque. Examples include conveyers, cranes, pumps, elevators, and compressors. This paper includes speed control of wound induction motor using MATLAB/Simulink for rotor resistance and slip power recovery method. The characteristics of these speed control methods are hence analysed.
Magnetic bearings support a load using magnetic levitation rather than physical contact, reducing friction and wear. They consist of electromagnets, position sensors, and a controller to levitate the rotating shaft. Active magnetic bearings use electromagnets and external power, while passive ones use permanent magnets without external power. Applications include maglev trains, compressors, and artificial hearts due to their ability to operate at high speeds and in vacuums or high temperatures with minimal friction.
This document discusses speed control methods for three-phase induction motors. It describes various speed control techniques including stator voltage control, stator frequency control, V/F control, and static rotor resistance control. It explains the advantages of speed control, such as energy savings and meeting different process requirements. Industrial applications of induction motor drives are also mentioned, such as in fans, compressors, pumps and machine tools.
V/F Control of Squirrel Cage Induction Motor Drives Without Flux or Torque Me...Waqas Tariq
Based on the popular constant volts per hertz principle, two improvement techniques are presented: keeping maximum torque constant or keeping magnetic flux constant. An open-loop inverter-three-phase squirrel-cage induction motor drive system that provides constant maximum torque or increased maximum torque and reduced slip speed at frequencies below the nominal frequency has been modeled, simulated and tested. Load performance analysis of the proposed system under different operation conditions was provided. These principles of operation are extended to the case of operation from variable frequency or variable voltage control method. Finally, the effects of the non-sinusoidal voltage and/or current wave shapes are covered. The results show that both suggested improvement techniques (constant torque or constant flux) improve the steady-state performance A.C. drive system with squirrel cage induction motors. The slip speed has been decreased and the starting torque and maximum torque have been increased, which means that the suggested control techniques can be used in drive systems with short time operating mode under light loads.
SELECTION OF DRIVES AND CONTROL SCHEMES FOR MACHINE TOOLS Praveen Kumar
SELECTION OF DRIVES AND CONTROL SCHEMES FOR MACHINE TOOLS
Machine tools and drives
Horse power requirement for driving the machine tools
MOTOR REQUIREMENTS FOR MACHINE TOOLS.
SELECTION OF MOTORS
Speed control of Drill press
Application of Motors to Planers, Shapers
Reversible motor drive quick return mechanism
GRINDING MACHINES
VFD
IRJET- Development of Modern Electrical Steering Gear System on Board Shi...IRJET Journal
This document discusses the development of modern electrical steering gear systems on ships that incorporate autopilot functionality. It begins with an overview of existing ship steering systems and their various operating modes, including autopilot, follow-up, non-follow-up, and emergency modes. It then presents the development of a new permanent magnet linear synchronous actuator (PMLSA) system as an alternative to traditional electro-hydraulic systems. The PMLSA is designed to provide high torque at low speeds for steering applications while offering benefits like reduced weight, size, maintenance needs, and improved efficiency compared to hydraulic systems. The document also discusses incorporating a magnetic compass feed unit as a backup navigation input for the autopilot in case of gyro compass failure.
This document discusses various methods of speed control for AC induction motors, including:
1. Stator side control methods like stator voltage control using an auto transformer or primary resistor, and stator frequency control.
2. Voltage/frequency control to maintain a constant flux by varying voltage and frequency together.
3. Pole changing methods that vary the motor's synchronous speed by changing the number of poles in the stator winding configuration.
4. Rotor side control methods are also discussed for wound rotor motors including rotor resistance control.
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology.
International Journal of Engineering Research and Applications (IJERA) aims to cover the latest outstanding developments in the field of all Engineering Technologies & science.
International Journal of Engineering Research and Applications (IJERA) is a team of researchers not publication services or private publications running the journals for monetary benefits, we are association of scientists and academia who focus only on supporting authors who want to publish their work. The articles published in our journal can be accessed online, all the articles will be archived for real time access.
Our journal system primarily aims to bring out the research talent and the works done by sciaentists, academia, engineers, practitioners, scholars, post graduate students of engineering and science. This journal aims to cover the scientific research in a broader sense and not publishing a niche area of research facilitating researchers from various verticals to publish their papers. It is also aimed to provide a platform for the researchers to publish in a shorter of time, enabling them to continue further All articles published are freely available to scientific researchers in the Government agencies,educators and the general public. We are taking serious efforts to promote our journal across the globe in various ways, we are sure that our journal will act as a scientific platform for all researchers to publish their works online.
This document discusses controlling magnetic flux density in active magnetic bearings. It describes how active magnetic bearings use electromagnets and feedback control loops to levitate and stabilize a rotating shaft without physical contact. Various sensor types are discussed for measuring the displacement of the levitated rotor, including inductive, eddy current, and capacitive sensors. The relationship between actuator current and magnetic force is explained, showing how current controls the flux density and resulting forces in the bearing.
Desmas(2014)-Preliminary Study on Magnetic Levitation Modeling Using PID ControlDesmas Patriawan
This paper proposes a magnetic levitation model using PID control. The model uses permanent magnets and electromagnets to generate magnetic levitation force and maintain a stable gap between the levitating object and the levitator. Simulation results show that while the initial model could not maintain a stable gap, adding PID control allowed the actual position to follow the reference position closely. Further simulations adding mass in stages showed that the PID controlled model could maintain the gap width, though a small 1mm difference occurred with the largest added mass of 150g. The study provides a preliminary simulation of a magnetic levitation system that could be further developed to maintain the desired gap even with added actual mass loads.
Development of high temperature magnetic bearingsjinfangliu
The document discusses a NASA/Electron Energy Corporation (EEC) Small Business Innovation Research (SBIR) project to develop high temperature permanent magnet biased magnetic bearings and motors. The project aims to utilize EEC's patented SmCo magnets that can operate up to 550°C to develop a technology demonstrator operating at 540°C, including a motor and radial/thrust magnetic bearings. Bench tests of a designed radial bearing show it can produce over 2800N of force at 500°C, around 86% of room temperature performance. A solid model and test apparatus are presented, demonstrating progress toward the project goals.
This document provides an overview of a course on electrical drives and control. It includes 5 units that cover topics such as drive motor characteristics, starting methods, speed control of DC and AC drives using conventional and solid state methods. The introduction defines electric drives and lists their basic elements and functions. It also describes factors that influence the choice of electrical drives such as steady state operation requirements, transient operation requirements, cost considerations, and environmental factors. Heating and cooling curves are also introduced to explain temperature rise in electric machines.
Design and Development of Passive Magnetic BearingIJMER
Passive Magnetic Bearings (PMB) are known for their non-contact and negligible friction
operations but these desirable characteristics of PMB can only be attained if proper designing of bearing
is carried out based on the applied load. To aid to the design of PMB, 3D Coulombian model to estimate
the load carrying capacity of magnetic bearings has been proposed. To exemplify the design procedure,
analyses of various configurations of magnetic bearings have been presented. To economize the magnetic
bearings, usage of easily available square magnets in stator made of aluminium has been proposed.
Finally, a case study has been included to illustrate the design of magnetic bearing.
Speed control of three phase im by vf open and close loop methodeSAT Journals
This document presents a simulation of speed control for a three-phase induction motor using open-loop and closed-loop V/F control methods. In the open-loop method, a PWM inverter drives the motor and the torque is observed to remain constant with varying rotor speed. In the closed-loop method, a PI controller provides feedback to vary the supply frequency to maintain a constant V/F ratio. Simulation results in MATLAB Simulink show that closed-loop control provides superior speed regulation compared to the open-loop method.
1. The document discusses electric drives and their components. Electric drives use electric motors as prime movers and include a power source, power modulator, motor, control unit, and sensing unit.
2. Power modulators can be converters, variable impedance circuits, or switching circuits. Converters provide adjustable voltage/current/frequency to control motor speed and torque. Variable impedance circuits and switching circuits are used to control motor parameters.
3. Electric drives are classified as individual drives, group drives, or multimotor drives depending on how many motors are used to drive different loads. Individual drives use one motor for all loads while group drives use one motor connected to multiple loads through pulleys. Multimotor
Modelling simulation and control of an active suspension systemIAEME Publication
This document discusses the modeling, simulation, and control of an active suspension system in MATLAB/Simulink. It begins by describing conventional passive and semi-active suspension systems, noting their tradeoffs between comfort and control. It then introduces active suspension systems, which can adjust their dynamics in real-time to provide both comfort and control. The document outlines modeling an active suspension system using a quarter car test setup and sensors to measure displacement, acceleration, and velocity. It describes using a linear electromagnetic motor actuated by a power amplifier and controlled via a PID controller to counteract road forces and keep the vehicle stable. The performance of the active suspension is simulated in MATLAB/Simulink and compared to a passive system.
The document provides information on the construction, working principle, and types of transformers. It begins by explaining the necessity of transformers in electrical power systems for stepping up and down voltages. The key points are:
- Transformers transfer power between circuits through electromagnetic induction without changing frequency. They have a primary and secondary winding wound around an iron core.
- Transformers can be used to step up or step down voltages depending on the ratio of turns in the primary and secondary windings. The voltage transformation ratio is equal to the ratio of turns.
- An ideal transformer has zero resistance windings, infinite core permeability, and is lossless. The voltage induced in each winding is directly proportional to its turns and the rate
Rotor Resistance Control of Wound Rotor Induction Generator (WRIG) using PSCA...Anmol Dwivedi
This document describes the modeling and simulation of a variable slip (type 2) wind turbine using a wound rotor induction generator in PSCAD/EMTDC. Key aspects modeled include the turbine aerodynamics, mechanical drive train, induction generator, and rotor resistance control system. Simulation results over different test cases demonstrate the system operating over a wide speed range and optimally extracting power from the wind by varying the rotor resistance of the induction generator.
Selection criteria of motors for various applicationsPrasanth Ravula
The document discusses factors to consider when selecting electric motors for various applications. It describes different types of motors including AC, DC, single phase, and three phase motors. Key selection criteria include the type of power available, size of motor needed based on the load, starting requirements, required speed, bearing type, motor base, and environmental conditions where the motor will operate. The document provides guidelines on matching these criteria to specific application requirements for proper motor selection.
1) Rolling mills require motors that can produce heavy torque at low RPM to roll metal ingots into blooms or slabs. DC motors are well-suited as they can provide high starting torque and wide speed variation.
2) Paper mill drives need variable speed control of multiple rolls. Synchronous motors connected via a Schrage motor allow independent yet coordinated speed control.
3) Marine drives utilize electric propulsion motors like induction or synchronous types to independently power propellers via alternators, providing flexibility and economical operation.
In recent advancements in electric machine and drives, wound rotor motor is extensively used. The merit of using wound rotor induction motor is to control speed/torque characteristics by inserting external resistance. Wound rotor induction motor can be used in the cases such as (a) low inrush current, (b) load requiring high starting torque, (c) lower starting current is required, (d) loads having high inertia, and (e) gradual built up of torque. Examples include conveyers, cranes, pumps, elevators, and compressors. This paper includes speed control of wound induction motor using MATLAB/Simulink for rotor resistance and slip power recovery method. The characteristics of these speed control methods are hence analysed.
Magnetic bearings support a load using magnetic levitation rather than physical contact, reducing friction and wear. They consist of electromagnets, position sensors, and a controller to levitate the rotating shaft. Active magnetic bearings use electromagnets and external power, while passive ones use permanent magnets without external power. Applications include maglev trains, compressors, and artificial hearts due to their ability to operate at high speeds and in vacuums or high temperatures with minimal friction.
This document discusses speed control methods for three-phase induction motors. It describes various speed control techniques including stator voltage control, stator frequency control, V/F control, and static rotor resistance control. It explains the advantages of speed control, such as energy savings and meeting different process requirements. Industrial applications of induction motor drives are also mentioned, such as in fans, compressors, pumps and machine tools.
V/F Control of Squirrel Cage Induction Motor Drives Without Flux or Torque Me...Waqas Tariq
Based on the popular constant volts per hertz principle, two improvement techniques are presented: keeping maximum torque constant or keeping magnetic flux constant. An open-loop inverter-three-phase squirrel-cage induction motor drive system that provides constant maximum torque or increased maximum torque and reduced slip speed at frequencies below the nominal frequency has been modeled, simulated and tested. Load performance analysis of the proposed system under different operation conditions was provided. These principles of operation are extended to the case of operation from variable frequency or variable voltage control method. Finally, the effects of the non-sinusoidal voltage and/or current wave shapes are covered. The results show that both suggested improvement techniques (constant torque or constant flux) improve the steady-state performance A.C. drive system with squirrel cage induction motors. The slip speed has been decreased and the starting torque and maximum torque have been increased, which means that the suggested control techniques can be used in drive systems with short time operating mode under light loads.
SELECTION OF DRIVES AND CONTROL SCHEMES FOR MACHINE TOOLS Praveen Kumar
SELECTION OF DRIVES AND CONTROL SCHEMES FOR MACHINE TOOLS
Machine tools and drives
Horse power requirement for driving the machine tools
MOTOR REQUIREMENTS FOR MACHINE TOOLS.
SELECTION OF MOTORS
Speed control of Drill press
Application of Motors to Planers, Shapers
Reversible motor drive quick return mechanism
GRINDING MACHINES
VFD
IRJET- Development of Modern Electrical Steering Gear System on Board Shi...IRJET Journal
This document discusses the development of modern electrical steering gear systems on ships that incorporate autopilot functionality. It begins with an overview of existing ship steering systems and their various operating modes, including autopilot, follow-up, non-follow-up, and emergency modes. It then presents the development of a new permanent magnet linear synchronous actuator (PMLSA) system as an alternative to traditional electro-hydraulic systems. The PMLSA is designed to provide high torque at low speeds for steering applications while offering benefits like reduced weight, size, maintenance needs, and improved efficiency compared to hydraulic systems. The document also discusses incorporating a magnetic compass feed unit as a backup navigation input for the autopilot in case of gyro compass failure.
This document discusses various methods of speed control for AC induction motors, including:
1. Stator side control methods like stator voltage control using an auto transformer or primary resistor, and stator frequency control.
2. Voltage/frequency control to maintain a constant flux by varying voltage and frequency together.
3. Pole changing methods that vary the motor's synchronous speed by changing the number of poles in the stator winding configuration.
4. Rotor side control methods are also discussed for wound rotor motors including rotor resistance control.
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology.
International Journal of Engineering Research and Applications (IJERA) aims to cover the latest outstanding developments in the field of all Engineering Technologies & science.
International Journal of Engineering Research and Applications (IJERA) is a team of researchers not publication services or private publications running the journals for monetary benefits, we are association of scientists and academia who focus only on supporting authors who want to publish their work. The articles published in our journal can be accessed online, all the articles will be archived for real time access.
Our journal system primarily aims to bring out the research talent and the works done by sciaentists, academia, engineers, practitioners, scholars, post graduate students of engineering and science. This journal aims to cover the scientific research in a broader sense and not publishing a niche area of research facilitating researchers from various verticals to publish their papers. It is also aimed to provide a platform for the researchers to publish in a shorter of time, enabling them to continue further All articles published are freely available to scientific researchers in the Government agencies,educators and the general public. We are taking serious efforts to promote our journal across the globe in various ways, we are sure that our journal will act as a scientific platform for all researchers to publish their works online.
This document discusses controlling magnetic flux density in active magnetic bearings. It describes how active magnetic bearings use electromagnets and feedback control loops to levitate and stabilize a rotating shaft without physical contact. Various sensor types are discussed for measuring the displacement of the levitated rotor, including inductive, eddy current, and capacitive sensors. The relationship between actuator current and magnetic force is explained, showing how current controls the flux density and resulting forces in the bearing.
Desmas(2014)-Preliminary Study on Magnetic Levitation Modeling Using PID ControlDesmas Patriawan
This paper proposes a magnetic levitation model using PID control. The model uses permanent magnets and electromagnets to generate magnetic levitation force and maintain a stable gap between the levitating object and the levitator. Simulation results show that while the initial model could not maintain a stable gap, adding PID control allowed the actual position to follow the reference position closely. Further simulations adding mass in stages showed that the PID controlled model could maintain the gap width, though a small 1mm difference occurred with the largest added mass of 150g. The study provides a preliminary simulation of a magnetic levitation system that could be further developed to maintain the desired gap even with added actual mass loads.
Surface roughness effect on the performance of a magnetic fluid based porous ...Alexander Decker
This document summarizes a study analyzing the performance of a porous rough secant shaped slider bearing using a magnetic fluid lubricant. The authors develop stochastic equations to model the pressure distribution and account for the random surface roughness. They present dimensionless equations for the load carrying capacity and friction. Graphs show that the magnetic fluid increases load capacity and decreases friction compared to conventional lubricants. However, increased porosity and surface roughness negatively impact performance. The positive effects of magnetization can reduce these negative impacts, especially for negatively skewed roughness and negative variance. The study concludes magnetic fluids improve bearing performance and can support loads even without fluid flow.
This document discusses the design and analysis of an active magnetic bearing system. It begins with an abstract that provides an overview of active magnetic bearings and their advantages over traditional bearings. It then describes the key components of an active magnetic bearing system, including the stator, rotor, position sensors, controller, and power amplifiers. It explains how these components work together using feedback control to levitate and position a rotor without physical contact. Application examples are given for uses in areas like power generation, transportation, and manufacturing. The document concludes by summarizing the capabilities and limitations of current active magnetic bearing technology.
This document summarizes research into improving the mechanical properties of neodymium-iron-boron bonded magnets through the addition of molybdenum disulfide (MoS2). Samples containing 0%, 0.5%, 1%, 1.5%, and 2% MoS2 by weight were produced and tested. Magnetic testing found that saturation magnetization and remanence increased with up to 1% MoS2 due to reduced friction, but decreased at higher amounts. Mechanical testing found density and compression strength increased with MoS2 due to reduced porosity, while hardness decreased slightly. Up to 1% MoS2 improved properties without harming magnetism, showing potential for stronger rare-earth magnets.
Magnetic bearing technology for high power machinesShehbaz Mulla
Magnetic bearings support rotating machinery without physical contact using magnetic levitation. They have advantages over conventional bearings like eliminating friction, lubrication needs, and contamination. There are two types - passive bearings that operate like mechanical bearings without control, and active bearings with sensors and controls that monitor shaft position and feed information back to continuously adjust the magnetic fields holding the rotor in place. Magnetic bearings enable more efficient, smaller, and lower maintenance machines.
This document describes the design and working of a permanent magnet generator project. It includes the following main points:
1) The generator uses permanent magnets and copper coils to generate electricity from rotational motion via electromagnetic induction. It is intended to extract energy freely from the environment.
2) The main components are neodymium magnets, a flywheel, driving and generating coils, and a rectifier circuit. The flywheel spins in between the magnetic fields produced by the driving coils and magnets to induce a voltage in the generating coils.
3) The generator is intended to efficiently produce electricity on a small household scale to power appliances. It has applications in remote areas with intermittent power and for military use.
The use of flywheels to capture and store rotational kinetic energy has been used in a range of systems for the past two hundred years or so. This document explores some of the modern applications of these devices and their implications for future use. An example of the calculation of the rotational kinetic energy is given and the parameters associated with this calculation are discussed.
The flywheel is a rotating mechanical device that stores rotational energy. It is typically made of steel and connects the engine's crankshaft to the transmission, smoothing out the power delivery from the engine. The flywheel's position is between the engine and clutch, and it is used to start the engine by providing rotational energy to the crankshaft when the starter is engaged. The principle of the flywheel has been known since Neolithic pottery wheels and spindles, and it was further developed during the Industrial Revolution for use in steam engines.
KERS systems capture kinetic energy lost during braking and store it to provide a power boost by releasing stored energy. There are two main types - electrical systems store energy in batteries while mechanical systems use a flywheel. Formula One introduced KERS in 2009 to increase overtaking opportunities by providing a short power boost. Mechanical KERS has higher efficiency than electrical systems as it avoids multiple energy conversions.
A flywheel, in essence is a mechanical battery - simply a mass rotating about an axis.Flywheels store energy mechanically in the form of kinetic energy.They take an electrical input to accelerate the rotor up to speed by using the built-in motor, and return the electrical energy by using this same motor as a generator.Flywheels are one of the most promising technologies for replacing conventional lead acid batteries as energy storage systems.
More than thirty years of research and application experience have led to Active Magnetic Bearings (AMB), which allow unique applications for rotating machinery with excellent performance. The main part is devoted to recent research topics, as a challenge to young researchers in rotor dynamics, mechatronics design and control. Active magnetic bearings, a typical mechatronics product have been successfully applied in industrial turbomachinery. Their main advantages are the contactless working principle, the frictionless suspension, and that they represent an active system. Therefore, the active magnetic bearings are well suited to operate contactless as actuator and sensor elements in rotating machinery. The report describes about the construction, working principles, advantages, disadvantages, applications & uses of AMBs. A unique aspect of the design is the two additional radial AMBs to allow the application of simulated destabilizing fluid or electromagnetic forces to the rotor. These forces are difficult to predict and can lead to rotordynamic instability of industrial machinery if not properly accounted for. The AMB provides a realistic platform to evaluate stabilizing control algorithms for high performance turbomachinery.
Analysis of Permanent Magnets Bearings in Flywheel Rotor DesignsIJERA Editor
This paper discusses analysis of permanent magnet bearing in flywheel rotor designs. This work focuses on
the advantages of using permanent magnets in flywheel rotor design as compared to that of the
convectional mode of levitating the rotor position. The use of permanent magnet in magnetic bearing
design to generate the steady state position of the magnetic field results in less variation of the force
exerted on the rotor when it deviates from the nominal position than when an electrical coil is used for the
same purpose. Theresults of the analysis shows that the magnetic bearing dynamics as well as its load
carryingcapacity improves when the rotor is offset from its central position. The use of permanent magnet
compared to current-carrying coils results in smaller overall size of magnetic bearing leading to a more
compact system design resulting in improved rotordynamic performance.
Design, Optimization and Analysis of a Radial Active Magnetic Bearing for Vib...ijtsrd
The most important aim of the project is to make use of the active vibration control technique to reduce vibration in composite shaft system using three nodded beam element. The fiber reinforced polymer FRP composite shaft is deliberate in this paper considering it as a Timoshenko beam. Three dissimilar isotropic rigid disks are mounted on it and also supported by two active magnetic bearings at its split ends. The work involves finite element, vibration and rotor dynamic analysis of the structure. Rotary inertia effect, gyroscopic effect kinetic energy and strain energy of the shaft are derived and studied. The governing equation is obtained by applying Hamilton's principle using finite element method in which four degrees of freedom at each node is considered. Active control scheme is applied through magnetic bearings by using a controller containing low pass filter, notch filter, sensor and amplifier which controls the current and correspondingly control the stability of the whole rotor shaft system. Campbell diagram, steadiness limit speed diagram and logarithmic decrement diagram are considered to establish the system stability. Effect of different types of stacking sequences are also studied and compared Jay Krishn Yadav | H. S. Sahu ""Design, Optimization and Analysis of a Radial Active Magnetic Bearing for Vibration Control"" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-3 | Issue-4 , June 2019, URL: https://www.ijtsrd.com/papers/ijtsrd24040.pdf
Paper URL: https://www.ijtsrd.com/engineering/mechanical-engineering/24040/design-optimization-and-analysis-of-a-radial-active-magnetic-bearing-for-vibration-control/jay-krishn-yadav
Abstract This Paper Proposes is to design a magnetic actuator to deal with the modeling and optimization of Solenoid actuator (Magnetic Actuator). The design is very important step for the study proportional solenoid valve. The magnetic actuator includes design optimization, micro analysis and calculations and experimental characterization one of the magnetic actuator. All these magnetic actuators work in sub- micron level movement used in micro system and valve applications. Proportional solenoid valve designed in find out the magnetic force (N), magnetic field intensity (A/m), magnetic flux density (Tesla or wb/m2). To enhance the magnetic force and reduction of size by magnetic field in air gap of solenoid valve. Permanent magnetic bias magnetic actuator study for bidirectional application using different permanent magnet material and optimization of size of armature. Key Words: Electromagnet, Solenoid actuator, Modeling, Design Rules,
1. direct torque control of induction motor with fuzzy controller a reviewMajdi Dadeq
This document reviews direct torque control of induction motors with fuzzy controllers. It begins by providing background on induction motors and their widespread use in industry. It then discusses direct torque control, which aims to directly control the stator flux and torque of induction motors through optimal selection of inverter switching vectors. The rest of the document discusses modeling induction motor drives using direct torque control with fuzzy logic applications and compares various techniques that have been proposed.
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology.
This document summarizes research on ultrasonic motors. It discusses how ultrasonic motors can be miniaturized for use in medical devices and robots. The researchers designed three types of ultrasonic motors with decreasing size down to 4mm long and 1.6mm diameter. The motors use a hollow cylindrical stator with piezoelectric plates to generate elliptical motion from two orthogonal bending modes. Finite element analysis was used to optimize the design. The motors' performance was characterized using a transient method measuring speed and calculating torque of a loaded rotor.
This document presents a study on using an artificial neural network technique for flux position estimation and sector selection in direct torque control of an induction motor. Direct torque control aims to provide quick torque response without complex transformations but suffers from high torque ripples. The proposed method uses a neural network for flux position estimation and sector selection to determine the optimal voltage vector, with the goal of reducing torque and flux ripples. The neural network structure is simple to facilitate short training and processing times. Simulation results show the neural network based controller provides high performance speed control of the induction motor.
Prospective Electromechanical Control Systems of Industrial Manipulator EffortsIJPEDS-IAES
The current electric drive of industrial manipulators is implemented on the
principle of speed control and position of the actuator, often donot provide
actuator motion as consistent with required process specifications. Taking
into account the disadvantages of existing control systems the new approach
to control systems engineering and implementation of industrial manipulators
electric drives using force balancing systems of actuator efforts control was
proposed. Application properties and implementation of efforts control
systems inside springy gears and mechanisms of industrial manipulators have
been studied. The efficient structure of electromechanical system, which
provides the desired balance the transfer object weight and dampening of
manipulators mechanical gears springy oscillations is proved. The studies
were performed on mathematical modeling and the prototype of industrial
manipulators, which confirmed the performance of control system potential
structure application and synthesized effort regulator which provide the
required performance factor. The potential electromechanical force balancing
systems is ably to increase industrial manipulators performance quality,
provides transfer and the desired positioning of load directly by operator.
Possibility of efficient application the scope increase of industrial
manipulators using the potential force balancing systems of efforts control is
defined.
Experimental Validation of Vibration Characteristics of Selected Centrifugal ...IRJET Journal
This document presents an experimental study on the vibration characteristics of a selected centrifugal pump. It begins with an introduction to pump vibrations and their causes. Next, it describes the methodology which includes measuring existing vibration levels, developing methods to reduce vibration, and experimenting with different isolation methods. Experimental results show that a grooved circular isolator is most effective at reducing vibration amplitudes while also increasing the first fundamental frequency to avoid resonance conditions. The conclusions determine that a grooved isolator is recommended for use with centrifugal pumps to minimize vibrations.
This document provides an overview of ultrasonic motors (USMs). It discusses the types of USMs, including standing wave and traveling wave motors that can be linear or rotary. It describes the basic working principle of how piezoelectric materials convert electrical energy to mechanical vibrations. The construction of USMs involves piezoelectric actuators, stators, rotors and casings. When voltage is applied, actuators vibrate and transfer energy to stators, creating surface waves that pull rotors to generate rotation. USMs offer advantages like high torque, precision, and suitability for harsh environments. Applications discussed include cameras, hard disks, robots and medical devices. A case study examines how USMs enabled precise robotic
Wind turbines form complex nonlinear mechanical systems exposed to uncontrolled wind
profiles. This makes turbine controller design a challenging task. As such, control of wind energy
conversion systems (WECS) is difficult due to the lack of systematic methods to identify requisite
robust and sufficiently stable conditions, to guarantee performance. The problem becomes more
complex when plant parameters become uncertain. This paper considers the wind energy curtailment
for which it provides a combinatorial planning model to maximize wind power utilization. The major
objective of this study is to develop an effective method for optimizing size of wind. A novel multiobjective
adaptation of the fuzzy based Harmony Search algorithm is proposed and tested for
efficiently solving the problem of optimally deploying wind turbines in wind farms. In this paper,
Harmony Search Algorithm (HSA) using fuzzy controller to achieve better optimization results and to
increase performance. A general formulation of this algorithm is presented together with an analytical
and mathematical modeling to solve the stability and performance of the system.
A bearing is a machine element that supports another moving element and allows relative motion while carrying a load. There are two main types of bearings: ball bearings, which use balls to separate the surfaces, and roller bearings, which use rollers. Roller bearings can carry greater loads than ball bearings in the same space due to line contact versus point contact. Magnetic bearings support loads using magnetic levitation without physical contact through the use of electromagnets and a control system. They have advantages like low friction, lack of wear, and ability to run without lubrication.
This document provides an overview of ultrasonic motors. It discusses that ultrasonic motors use piezoelectric elements to generate ultrasonic vibrations that produce rotational or linear motion. The vibrations are amplified through resonance. Advantages over electromagnetic motors include high torque at low speeds, compact size, and insensitivity to magnetic fields. The document then describes various prototypes of linear and rotary ultrasonic motors and their design and modeling. It provides details on the operating principles and applications of ultrasonic motors.
Design and Analysis of Mechanism for Dynamic Characterization of Power Transm...iosrjce
Power transmission systems are being widely used for transmission of power between two members.
Once a particular transmission system is realized it needs to be qualified before its course of application. As
part of this intended torque of the transmission systems needs to be measured and tested. Conventional means of
dynamic characterization of power transmission system has got the demerit of energy consumption to a greater
extent. Because of this more effort is to be put in terms of power for the sake of testing the intended system.
Great need exists for a system which consumes less or ideally no energy while performing test. This project
aims at evolution of a novel technique for evaluating the torque transmitting capability of power transmission
systems without consuming more energy. To start with all the subsystems of the proposed design will be
identified and each of them will be designed for getting their dimensions. Then these dimensional models will be
transformed to solid model of the assembled configuration using 3D CAD software. Functional load which will
be experienced by this design will be assessed and structural analysis will be carried out against these loads
using Finite Element Method (FEM) in commercial FEA software i.e. ANSYS
The document describes the design and analysis of a mechanism to dynamically characterize power transmission systems without consuming significant energy. It involves using an electro-mechanical clutch connected to a motor via pulleys of different sizes to measure the torque transmitting capability of a transmission system by gradually increasing the load torque until slip occurs. Structural analysis using FEA found the design to be safe with a factor of safety above the minimum required.
1) The document discusses using a STATCOM (Static Synchronous Compensator) to improve transient stability in a 14-bus power system with 5 generators.
2) Simulation results show that a STATCOM is effective at damping oscillations and improving stability of voltage, active power, reactive power, and rotor speed/angle when a fault is applied.
3) Key findings are that a STATCOM reduces settling time and helps the system regain stability faster after a disturbance by damping out oscillations in various system parameters.
“Test rig on Eddy current braking system” is a very great innovation on its own and is specially made for the purpose
to stop the wheel in minimum time. Brakes are the crucial components in any mobile system which are generally used to stop
the motion of any mobile. Such type of component must be checked by using the highly accurate methodology in order to
access its functional performance in advance. The inspection methodology of brakes should be accurate with less time
consuming procedure for its inspection. This test rig will check the brake in the least time which leads to a reduction of nonproductive
time and improves brake efficiency.
FEA Simulation for Vibration Control of Shaft System by Magnetic Piezoelectri...IOSR Journals
1) The document describes a finite element analysis simulation of a shaft system to evaluate the effectiveness of magnetic piezoelectric control mounts for vibration damping.
2) The shaft is 200mm long, rotates at 700rpm, and is subjected to a hammer load of 220N. Modal and harmonic analyses are conducted with and without control mounts.
3) The results show that with control mounts, natural frequencies are reduced to 2-9Hz from 2000-9000Hz, deformation is reduced by 60%, amplitude is reduced by 98%, and vibration is damped by 99%, demonstrating the control mounts are an effective vibration damping method.
1) The document describes a finite element analysis simulation of a shaft system to evaluate the effectiveness of magnetic piezoelectric control mounts for vibration damping.
2) The shaft is 200mm long, rotates at 700rpm, and is subjected to a hammer load of 220N. Modal and harmonic analyses are conducted with and without control mounts.
3) The results show that with control mounts, natural frequencies are reduced to 2-9Hz from 2000-9000Hz, deformation is reduced by 60%, amplitude is reduced by 98%, and vibration is damped by 99%, demonstrating the control mounts are an effective vibration damping method.
1. International Journal of Engineering and Technical Research (IJETR)
ISSN: 2321-0869 (O) 2454-4698 (P), Volume-4, Issue-4, April 2016
36 www.erpublication.org
Abstract— The use of bearings is essential to all types of
machines, in that they provide the function of supporting
another piece or component in a desired position. Two major
types include radial and axial bearings. A further classification
can be made into active and passive bearings, which is addressed
in this paper. More than thirty years of research and application
have led to active magnetic bearings (AMB). Active magnetic
bearing can support a shaft, rotor without any physical contact
and enables the user to precisely control shaft or rotor position
and vibration as a function of time and other parameters. This
frictionless and programmable features have made AMB
suitable to meeting the demand for higher speed, higher
efficiency and reliability of rotating machinery in many
industrial application including flywheel energy storage,
momentum wheels, turbo machineries, precision machineries,
vacuum pumps, medical devices. Other features of AMB, such as
the absence of contamination by lubrication or mechanical wear,
low energy consumption and low maintenance cost are
prevailing now. This paper reviews the components and
working principles of AMB, which requires the basic
understanding of rotor dynamics, electromagnetism, power
electronics and control theories. AMB is typical mechatronics
product. Furthermore, the use AMB as key to smart machinery
allows the integration of machine into control of a whole
production process and to manage safety and maintenance
issues.
Index Terms— Control theories, Magnetic bearing,
Mechatronics, Rotor dynamics
I. INTRODUCTION
Active magnetic bearings are replacing oil-lubricated
bearings in many applications. The benefits of using magnetic
bearings in rotating machinery include higher reliability with
little or no maintenance, reduced frictional losses, no
contaminating or flammable lubricants, reduced machine
vibration, and improved health monitoring and diagnostics.
However, despite these advantages, the application of
magnetic bearings has been limited in the past by the large
size of the magnetic bearings, the complexity of integrating
the magnetic bearings into the machine, the need for a large
external control system, and the high cost. Recent advances in
magnetic bearing technology, including miniaturization,
simplicity and integration have overcome many of these
limitations. As a result, magnetic bearings are replacing
oil-lubricated bearings for many new types of machines in a
variety of industries.
Active magnetic bearing system levitates the rotating shaft
and maintains it in position by applying controlled
electromagnetic forces on the rotor in radial and axial
directions. The active magnetic bearing is the principle which
is actually used most often among the magnetic suspensions.
Shubham Naikwad, Mechanical Engineering Department,
B.E.(pursuing) from Sinhgad College of Engineering and Savitribai Phule
University of Pune, Pune, India.
A sensor measures the displacement of the rotor from its
reference position, a microcontroller as a controller derives a
control signal from the measures and gives signal to a power
amplifier into a control current, and the control current
generates the magnetic forces within the actuating magnet in
such a way that the rotor remains in its hovering position. This
enables very high rotational speed to be realized. A magnetic
bearing is free of lubricant, which avoids servicing and also
enables use in clean room environment. Maintenance is also
decreased due to absence of surface wear, so that as long as
the control system functions as intended, there could be no
maintenance. One major disadvantage to using magnetic
bearings is their complexity. A very knowledgeable person in
the field is generally required to design and implement a
successful system. Because of the large amount of effort and
time required for development and the increase in the number
of components, compared to a traditional bearing, the initial
costs are much higher. However, depending on the
application, the return on investment for these initial costs
could be relatively short for a system, for example, that runs
with a much higher efficiency due to the lack of bearing
friction resistance.[1]
II. GLANCE OF HISTORY
The table below lists several early patents for active
magnetic bearings suspension can be found out but are
excluded here because they consist of assemblies of
permanent magnets of problematic Earnshaw’s Theorem.
Table 1 : Early U. S. Patents in AMB [2]
Inventor Year Patent no. Title
Beams Holmes 1941 2,256,937 Suspension of Rotatable
bodies
Beams 1954 2,691,306 Magnetically supported
Rotated bodies.
Beams 1962 3,041,482 Apparatus for rotating
freely suspended body
Beams 1965 3,196,694 Magnetic suspension
bodies
Wolf 1967 3,316,032 Poly phase magnetic
suspension transformer
Lyman 1971 3,565,495 Magnetic suspension
apparatus
Habermann 1973 3,731,984 Magnetic bearing block
device for supporting a
vertical shaft adapted
for rotating at high
speed.
Habermann,
Brunet
1977 4,012,083 Magnetic bearings
Habermann,
Brunet, Leclere
1978 4,114,960 Radial displacement
detector device for a
magnetic bearing
Meeks,
Crawford R
1992 5,111,102 Magnetic bearing
structure
Study of Active Magnetic Bearing
Shubham Naikwad
2. Study of Active Magnetic Bearing
37 www.erpublication.org
III. PRINCIPLE AND OPERATION OF AMB
Active magnetic bearing (AMB) works on the
electromagnetic suspension principles. Electromagnetic
suspension is the magnetic levitation of an object achieved by
constantly altering the strength of a magnetic field produced
by electromagnets using a feedback loop. A charged body
cannot rest in stable equilibrium when placed in a pure
electrostatic field or magneto static field (Earnshaw’s
theorem) [3]-[4]. In these kinds of fields an unstable
equilibrium condition may exists, also static fields may
provide to fail the stability, electromagnet suspension works
by continually altering the current sent to electromagnets to
change the strength of the magnetic field and allows a suitable
levitation to occur [5]. In EMS a feedback loop which
continuously adjusts one or more electromagnets to correct
the objects motion is used to cancel the instability. A set of
power amplifiers which supply current to the electromagnets,
a controller and gap sensors with associated electronics to
provide the feedback required to control the position of the
rotor within the gap [6]. The power amplifier supplies equal
bias current to two pairs of electromagnets on opposite sides
of the rotor. Then constant tug-of-war is mediated by the
controller which offsets the bias current by equal and opposite
perturbations of current as the rotor deviates from its center
position. The gap is monitored by a current sensors and sense
in a differential mode. The power amplifiers operation can be
achieved by Pulse Width Modulation (PWM) technique. The
controller is usually a Proportional Integral Derivative (PID)
controller [7].
Figure 1 :- Principle operation of bearing [2]
IV. WORKING OF ACTIVE MAGNETIC BEARING
A typical AMB is made up of the following elements:
Stator
Rotor
Sensors
Electromagnets
AMB can be configured as either radial or thrust bearing.
These elements are shown in the diagram below.
Figure 2:- Elements of AMB [8]
The power amplifiers supply equal bias current to two pairs
of electromagnets on opposite sides of a rotor. The controller
offsets the required bias current by equal but opposite
perturbations of current as the rotor deviates by a small
amount from its center position. The gap sensors are usually
inductive in nature and continuously sensing the gap between
rotor and the bearing. The sensor measures the position of the
body. The control electronics then calculates the right current
to suspend the ball.
This current is set by the amplifier. The resulting force is
within limits proportional to the square of the current and
inversely proportional to the square of the position.
)^2
Controller uses microprocessor to allow the whole system
function in a stable manner.
Typical active magnetic bearing system components:
Stator
Rotor
2 Radial Magnetic Bearings
1 Thrust (Axial) Magnetic Bearing
Controller
Power Supply
UPS (Uninterruptable Power Supply)
Figure 3:- Active magnetic bearing system components [9]
3. International Journal of Engineering and Technical Research (IJETR)
ISSN: 2321-0869 (O) 2454-4698 (P), Volume-4, Issue-4, April 2016
38 www.erpublication.org
Getting information from the AMB system (Health or
Condition Monitoring):
Synchrony has dedicated many years of research and
development into creating and supplying its proprietary
machine health monitoring software and condition
monitoring. Much of the ability to miniaturize and simplify
physical attributes of magnetic bearing systems is due to
Synchrony's technological breakthroughs in controls
software.
Magnetic bearings in industrial applications offer greater
reliability than ever because of remote bearing monitoring
capabilities that let users recognize and head off potential
trouble before it even starts. That helps set Synchrony®
products apart from earlier generations of magnetic bearings.
Superior bearing vibration monitoring allows continuous
system performance feedback to help you get the most from
magnetic bearings capabilities, while keeping costs down.
Health monitoring of magnetic bearings previously
required large, expensive hardware. Synchrony builds sensors
right into radial and thrust bearings, and each "smart" bearing
comes with its own IP address, so information can be fed into
an HMI that’s easy to use and configurable to each operator’s
needs. Regardless of your location.[9]
Bearing monitoring capabilities:
Monitor trends and changes in operating conditions
Predict and schedule pre-emptive maintenance shutdowns
Maximize uptime and minimize component damage
Ensure maximum efficiency
V. DESIGN, COST AND PERFORMANCE ISSUE
Currently, there is still no industrial or international
standard for AMB design procedures and performance
requirements. The International Organization for
Standardization (ISO) and International Electro technical
Committee (IEC) are still preparing a draft of ISO 14839 for
this purpose. The AMB ISO 14839 draft can be accessed at an
internet address shown in reference [10].
There are several variations in the AMB systems
configuration. These variations exist because of the need for
lower hardware cost and more fault tolerant AMB systems.
For example, an AMB system which is so called
“self-sensing”, does not require position sensors which means
lower hardware cost. However, the stability margin and
robustness can easily degrade. So does the AMB system that
only has 3 poles of electromagnets in each bearing.
The design of AMB systems need to consider the worst
case scenario such as loss of control due to faulty
hardware/software components, and due to large external
disturbances such as an earthquake or other vibrations. For
this purpose, auxiliary bearings are always incorporated as a
back-up. The diameter of auxiliary bearings is sized such that
the electromagnets are well protected during the “crash” and
during power start-up and termination.
An example of hardware cost in the year of 2006 for typical
AMB systems is shown in Table 2 assuming a mass
production i.e. At least a thousand AMB units for a vertical
rotor with mass of 250 kg, diameter about 5 cm, maximum
speed about 25 thousand RPM, distance between bearings
about 0.5 meter, and maximum force per axis about 250N.
Table 2:- AMB components cost estimate
AMB components Estimated
cost
(US Dollar)
2 electromagnets+ position sensors 300-500
8 PWM power amplifiers, @ 50 watt
max
400-800
DSP+electronics +power supplies 750-1500
Wiring 100-200
2 auxiliary bearings 50-200
Total 1700-3200
It is worth noted that in some designs and applications, the
total electrical loss of AMB systems may be higher than the
power loss due to mechanical friction of conventional
bearings. The wiring of power lines from power amplifiers to
electromagnets should be made as short as possible in order to
reduce electrical resistance. However, in many applications
the other benefits of AMB already overcome this electrical
loss such that AMB is still an attractive choice. Adaptive
Vibration Control (AVC) feature in AMB systems is useful
after a certain RPM. Using a gradient method to minimize
cost function of influence efficient matrix, AVC can
“on-the-fly” reduce or eliminate synchronous vibration due to
mass unbalance. Because of its great advantage, this feature is
almost always incorporated in the AMB systems.[9]
VI. MAJOR PLAYERS IN AMB TECHNOLOGY
There have been numerous AMB manufacturers in the
world [8]-[11]. The two most industrious ones are S2M in
France and Revolve in Calgary, Canada. S2M has sold
thousands AMB systems primary for compression systems for
oil and gas production industry. Another AMB company,
Synchrony focuses on “high grade” fault tolerant AMB
systems that can be used by aerospace industries and future
aircraft engines.
Due to the rapid progress in electronics including DSP
technology, there are chances of avenues for further research
in AMB. Performance improvement, cost reduction, and
additional design objectives within specific applications are
some of the examples. In the recent years, researchers
working on magnetic bearings have been aggressively
focusing in areas such as (1) studies to utilize modern control
methods including multi-variable controls, robust controls,
non-linear controls, and adaptive controls in order to
minimize rotor vibration; (2) studies of levitating more
flexible rotors; (3) studies of self-sensing magnetic bearings;
(4) studies on the joint use of magnetic bearings for levitation
and motor-stators for rotation; (5) hybrid passive and AMB;
and (6) studies on zero-power magnetic bearings using
superconductor materials. Most of the above research topics
are conducted at the three most notable AMB research and
academic centers in the world [12-13]: (1) Rotating
Machinery and Controls Laboratory (ROMAC) at the
University of Virginia, Virginia, USA; (2) The International
Center for Magnetic Bearings (ICMB) at The Institute of
Robotics, ETH Zurich, Switzerland; and (3) Institute for
4. Study of Active Magnetic Bearing
39 www.erpublication.org
Machine Dynamics and Measurements (MTMD), Viena
University of Technology, Vienna, Austria.
VII. APLLICATION
1. Magnetic bearings are increasingly used in industrial
machines such as compressors, turbines, pumps, motors and
generators
2. Magnetic bearings are commonly used in watt-hour meters
by electric utilities to measure home power consumption.
3. Magnetic bearings are also used in high-precision
instruments and to support equipment in a vacuum.
4. Magnetic bearings are also used to support Maglev trains
in order to get low noise and smooth ride by eliminating
physical contact surfaces.
5. A very interesting new application of magnetic bearings is
their use in Artificial hearts.
6. Now-a-days, they are in service in such industrial
applications as Electric power generation, Petroleum
Refining, Machine tool operation and Natural gas pipelines.
VIII. LIMITATION OF STUDY
Active magnetic bearing are not much used in the industries
because its complexity and high cost than conventional
bearing despite of AMB provides many advantages. It’s a
pressing need that the attempts should be made to reduce the
complexity and cost of AMB by experiments and further
studies on AMB. Synchrony AMB’s manufacturer has been
working on the same. This will helps for small scale industries
to adopt the use of AMB to increase performance of
machineries. For that work on the AMB components and this
components can be optimize so that AMB can use as
equivalent to conventional mechanical bearing.
IX. CONCLUSION
The AMB technology has been briefly reviewed including
its advantages, components, working principles, cost and
performance. Some design and implementation issues have
been also discussed. The authors believe that AMB systems
are still relatively more expensive than conventional
mechanical bearings, some studies are needed to tackle the
cost and complexity issues; therefore the massive used of
AMB in industries is still prohibitive despite of the many
benefits offered. The AMB will still not completely replace
conventional bearings in rotating machineries in the near
future. However, AMB can find its place well in a limited
volumes of high performance rotating machines.
ACKNOWLEDGMENT
The author sincerely thanks to thank Setiawan J.D and
Jeffery Hilyard for their work in active magnetic bearing
research domain from which author get an idea to study this
topic.
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