Download or read book Room Temperature Characterization of a Magnetic Bearing for Turbomachinery written by and published by . This book was released on 2002 with total page 16 pages. Available in PDF, EPUB and Kindle. Book excerpt: Open loop, experimental force and power measurements of a three-axis, radial, heteropolar magnetic bearing at room temperature for rotor speeds up to 20,000 RPM are presented in this paper. The bearing, NASA Glenn Research Center's and Texas A & M's third generation high temperature magnetic bearing, was designed to operate in a 1000 deg. F (540 deg. C) environment and was primarily optimized for maximum load capacity. The experimentally measured force produced by one C-core of this bearing was 630 lb. (2.8 kN) at 16 A, while a load of 650 lbs (2.89 kN) was predicted at 16 A using 1D circuit analysis. The maximum predicted radial load for one of the three axes is 1,440 lbs (6.41 kN) at room temperature. The maximum measured load of an axis was 1050 lbs. (4.73 kN). Results of test under rotating conditions showed that rotor speed has a negligible effect on the bearing's load capacity. A single C-core required approximately 70 W of power to generate 300 lb (1.34 kN) of magnetic force. The room temperature data presented was measured after three thermal cycles up to 1000 deg. F (540 deg. C), totaling six hours at elevated temperatures.

Download or read book Room Temperature Characterization of a Magnetic Bearing for Turbomachinery written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-06-20 with total page 30 pages. Available in PDF, EPUB and Kindle. Book excerpt: Open loop, experimental force and power measurements of a three-axis, radial, heteropolar magnetic bearing at room temperature for rotor speeds up to 20,000 RPM are presented in this paper. The bearing, NASA Glenn Research Center's and Texas A&M's third generation high temperature magnetic bearing, was designed to operate in a 1000 F (540 C) environment and was primarily optimized for maximum load capacity. The experimentally measured force produced by one C-core of this bearing was 630 lb. (2.8 kN) at 16 A, while a load of 650 lbs (2.89 kN) was predicted at 16 A using 1D circuit analysis. The maximum predicted radial load for one of the three axes is 1,440 lbs (6.41 kN) at room temperature. The maximum measured load of an axis was 1050 lbs. (4.73 kN). Results of test under rotating conditions showed that rotor speed has a negligible effect on the bearing's load capacity. A single C-core required approximately 70 W of power to generate 300 lb (1.34 kN) of magnetic force. The room temperature data presented was measured after three thermal cycles up to 1000 F (540 C), totaling six hours at elevated temperatures. Montague, Gerald and Jansen, Mark and Provenza, Andrew and Jansen, Ralph and Ebihara, Ben and Palazzolo, Alan Glenn Research Center NASA/TM-2002-211904, NAS 1.15:211904, ARL-TR-2858, E-13594

Download or read book High Speed Operation and Testing of a Fault Tolerant Magnetic Bearing written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-06-24 with total page 28 pages. Available in PDF, EPUB and Kindle. Book excerpt: Research activities undertaken to upgrade the fault-tolerant facility, continue testing high-speed fault-tolerant operation, and assist in the commission of the high temperature (1000 degrees F) thrust magnetic bearing as described. The fault-tolerant magnetic bearing test facility was upgraded to operate to 40,000 RPM. The necessary upgrades included new state-of-the art position sensors with high frequency modulation and new power edge filtering of amplifier outputs. A comparison study of the new sensors and the previous system was done as well as a noise assessment of the sensor-to-controller signals. Also a comparison study of power edge filtering for amplifier-to-actuator signals was done; this information is valuable for all position sensing and motor actuation applications. After these facility upgrades were completed, the rig is believed to have capabilities for 40,000 RPM operation, though this has yet to be demonstrated. Other upgrades included verification and upgrading of safety shielding, and upgrading control algorithms. The rig will now also be used to demonstrate motoring capabilities and control algorithms are in the process of being created. Recently an extreme temperature thrust magnetic bearing was designed from the ground up. The thrust bearing was designed to fit within the existing high temperature facility. The retrofit began near the end of the summer, 04, and continues currently. Contract staff authored a NASA-TM entitled "An Overview of Magnetic Bearing Technology for Gas Turbine Engines", containing a compilation of bearing data as it pertains to operation in the regime of the gas turbine engine and a presentation of how magnetic bearings can become a viable candidate for use in future engine technology. DeWitt, Kenneth and Clark, Daniel Glenn Research Center

Download or read book An Overview of Magnetic Bearing Technology for Gas Turbine Engines written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-06-21 with total page 28 pages. Available in PDF, EPUB and Kindle. Book excerpt: The idea of the magnetic bearing and its use in exotic applications has been conceptualized for many years, over a century, in fact. Patented, passive systems using permanent magnets date back over 150 years. More recently, scientists of the 1930s began investigating active systems using electromagnets for high-speed ultracentrifuges. However, passive magnetic bearings are physically unstable and active systems only provide proper stiffness and damping through sophisticated controllers and algorithms. This is precisely why, until the last decade, magnetic bearings did not become a practical alternative to rolling element bearings. Today, magnetic bearing technology has become viable because of advances in micro-processing controllers that allow for confident and robust active control. Further advances in the following areas: rotor and stator materials and designs which maximize flux, minimize energy losses, and minimize stress limitations; wire materials and coatings for high temperature operation; high-speed micro processing for advanced controller designs and extremely robust capabilities; back-up bearing technology for providing a viable touchdown surface; and precision sensor technology; have put magnetic bearings on the forefront of advanced, lubrication free support systems. This paper will discuss a specific joint program for the advancement of gas turbine engines and how it implies the vitality of magnetic bearings, a brief comparison between magnetic bearings and other bearing technologies in both their advantages and limitations, and an examination of foreseeable solutions to historically perceived limitations to magnetic bearing. Clark, Daniel J. and Jansen, Mark J. and Montague, Gerald T. Glenn Research Center NASA/TM-2004-213177, ARL-TR-3254, E-14672

Download or read book Vibration Control in Turbomachinery Using Active Magnetic Journal Bearings written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-08-04 with total page 228 pages. Available in PDF, EPUB and Kindle. Book excerpt: The effective use of active magnetic bearings for vibration control in turbomachinery depends on an understanding of the forces available from a magnetic bearing actuator. The purpose of this project was to characterize the forces as functions shaft position. Both numerical and experimental studies were done to determine the characteristics of the forces exerted on a stationary shaft by a magnetic bearing actuator. The numerical studies were based on finite element computations and included both linear and nonlinear magnetization functions. Measurements of the force versus position of a nonrotating shaft were made using two separate measurement rigs, one based on strain gage measurement of forces, the other based on deflections of a calibrated beam. The general trends of the measured principal forces agree with the predictions of the theory while the magnitudes of forces are somewhat smaller than those predicted. Other aspects of theory are not confirmed by the measurements. The measured forces in the normal direction are larger than those predicted by theory when the rotor has a normal eccentricity. Over the ranges of position examined, the data indicate an approximately linear relationship between the normal eccentricity of the shaft and the ratio of normal to principal force. The constant of proportionality seems to be larger at lower currents, but for all cases examined its value is between 0.14 and 0.17. The nonlinear theory predicts the existence of normal forces, but has not predicted such a large constant of proportionality for the ratio. The type of coupling illustrated by these measurements would not tend to cause whirl, because the coupling coefficients have the same sign, unlike the case of a fluid film bearing, where the normal stiffness coefficients often have opposite signs. They might, however, tend to cause other self-excited behavior. This possibility must be considered when designing magnetic bearings for flexible rotor applications, such as gas t...

Download or read book Development and Testing of an Axial Halbach Magnetic Bearing written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-05-30 with total page 30 pages. Available in PDF, EPUB and Kindle. Book excerpt: The NASA Glenn Research Center has developed and tested a revolutionary Axial Halbach Magnetic Bearing. The objective of this work is to develop a viable non-contact magnetic thrust bearing utilizing Halbach arrays for all-electric flight, and many other applications. This concept will help to reduce harmful emissions, reduce the Nation s dependence on fossil fuels and mitigate many of the concerns and limitations encountered in conventional axial bearings such as bearing wear, leaks, seals and friction loss. The Axial Halbach Magnetic Bearing is inherently stable and requires no active feedback control system or superconductivity as required in many magnetic bearing designs. The Axial Halbach Magnetic Bearing is useful for very high speed applications including turbines, instrumentation, medical systems, computer memory systems, and space power systems such as flywheels. Magnetic fields suspend and support a rotor assembly within a stator. Advanced technologies developed for particle accelerators, and currently under development for maglev trains and rocket launchers, served as the basis for this application. Experimental hardware was successfully designed and developed to validate the basic principles and analyses. The report concludes that the implementation of Axial Halbach Magnetic Bearings can provide significant improvements in rotational system performance and reliability.Eichenberg, Dennis J. and Gallo, Christopher A. and Thompson, William K.Glenn Research CenterMAGNETIC BEARINGS; THRUST BEARINGS; HIGH SPEED; MAGNETIC SUSPENSION; MAGNETIC FIELDS; PARTICLE ACCELERATORS; RELIABILITY; SPACECRAFT POWER SUPPLIES; MEMORY (COMPUTERS); ROTORS; STATORS; TURBINES

Download or read book High Speed High Temperature Fault Tolerant Operation of a Combination Magnetic Hydrostatic Bearing Rotor Support System for Turbomachinery written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-06-21 with total page 28 pages. Available in PDF, EPUB and Kindle. Book excerpt: Closed loop operation of a single, high temperature magnetic radial bearing to 30,000 RPM (2.25 million DN) and 540 C (1000 F) is discussed. Also, high temperature, fault tolerant operation for the three axis system is examined. A novel, hydrostatic backup bearing system was employed to attain high speed, high temperature, lubrication free support of the entire rotor system. The hydrostatic bearings were made of a high lubricity material and acted as journal-type backup bearings. New, high temperature displacement sensors were successfully employed to monitor shaft position throughout the entire temperature range and are described in this paper. Control of the system was accomplished through a stand alone, high speed computer controller and it was used to run both the fault-tolerant PID and active vibration control algorithms. Jansen, Mark and Montague, Gerald and Provenza, Andrew and Palazzolo, Alan Glenn Research Center NASA/TM-2004-212952, ARL-TR-3156, GT2004-53321, NAS 1.15-212952, E-14391

Download or read book Control Study for Five Axis Dynamic Spin Rig Using Magnetic Bearings written by National Aeronautics and Space Adm Nasa and published by . This book was released on 2018-09-28 with total page 28 pages. Available in PDF, EPUB and Kindle. Book excerpt: The NASA Glenn Research Center (GRC) has developed a magnetic bearing system for the Dynamic Spin Rig (DSR) with a fully suspended shaft that is used to perform vibration tests of turbomachinery blades and components under spinning conditions in a vacuum. Two heteropolar radial magnetic bearings and a thrust magnetic bearing and the associated control system were integrated into the DSR to provide magnetic excitation as well as non-contact mag- netic suspension of a 15.88 kg (35 lb) vertical rotor with blades to induce turbomachinery blade vibration. For rotor levitation, a proportional-integral-derivative (PID) controller with a special feature for multidirectional radial excitation worked well to both support and shake the shaft with blades. However, more advanced controllers were developed and successfully tested to determine the optimal controller in terms of sensor and processing noise reduction, smaller rotor orbits, more blade vibration amplitude, and energy savings for the system. The test results of a variety of controllers that were demonstrated up to 10.000 rpm are shown. Furthermore, rotor excitation operation and conceptual study of active blade vibration control are addressed. Choi, Benjamin and Johnson, Dexter and Provenza, Andrew and Morrison, Carlos and Montague, Gerald Glenn Research Center NASA/TM-2003-212295, GT2003-38912, NAS 1/15:212295, E-13857...

Download or read book Development and Testing of a Radial Halbach Magnetic Bearing written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-05-29 with total page 40 pages. Available in PDF, EPUB and Kindle. Book excerpt: The NASA John H. Glenn Research Center has developed and tested a revolutionary Radial Halbach Magnetic Bearing. The objective of this work is to develop a viable non-contact magnetic bearing utilizing Halbach arrays for all-electric flight, and many other applications. This concept will help reduce harmful emissions, reduce the Nation s dependence on fossil fuels and mitigate many of the concerns and limitations encountered in conventional axial bearings such as bearing wear, leaks, seals and friction loss. The Radial Halbach Magnetic Bearing is inherently stable and requires no active feedback control system or superconductivity as required in many magnetic bearing designs. The Radial Halbach Magnetic Bearing is useful for very high speed applications including turbines, instrumentation, medical applications, manufacturing equipment, and space power systems such as flywheels. Magnetic fields suspend and support a rotor assembly within a stator. Advanced technologies developed for particle accelerators, and currently under development for maglev trains and rocket launchers, served as the basis for this application. Experimental hardware was successfully designed and developed to validate the basic principles and analyses. The report concludes that the implementation of Radial Halbach Magnetic Bearings can provide significant improvements in rotational system performance and reliability.Eichenberg, Dennis J. and Gallo, Christopher A. and Thompson, William K.Glenn Research CenterMAGNETIC BEARINGS; ACTIVE CONTROL; SPACECRAFT POWER SUPPLIES; PARTICLE ACCELERATORS; MAGNETIC SUSPENSION; FOSSIL FUELS; FRICTION; SUPERCONDUCTIVITY; RELIABILITY; MANUFACTURING; MEDICAL EQUIPMENT

Download or read book Fault Tolerant Homopolar Magnetic Bearings written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-06-20 with total page 38 pages. Available in PDF, EPUB and Kindle. Book excerpt: Magnetic suspensions (MS) satisfy the long life and low loss conditions demanded by satellite and ISS based flywheels used for Energy Storage and Attitude Control (ACESE) service. This paper summarizes the development of a novel MS that improves reliability via fault tolerant operation. Specifically, flux coupling between poles of a homopolar magnetic bearing is shown to deliver desired forces even after termination of coil currents to a subset of failed poles . Linear, coordinate decoupled force-voltage relations are also maintained before and after failure by bias linearization. Current distribution matrices (CDM) which adjust the currents and fluxes following a pole set failure are determined for many faulted pole combinations. The CDM s and the system responses are obtained utilizing 1D magnetic circuit models with fringe and leakage factors derived from detailed, 3D, finite element field models. Reliability results are presented vs. detection/correction delay time and individual power amplifier reliability for 4, 6, and 7 pole configurations. Reliability is shown for two success criteria, i.e. (a) no catcher bearing contact following pole failures and (b) re-levitation off of the catcher bearings following pole failures. An advantage of the method presented over other redundant operation approaches is a significantly reduced requirement for backup hardware such as additional actuators or power amplifiers. Li, Ming-Hsiu and Palazzolo, Alan and Kenny, Andrew and Provenza, Andrew and Beach, Raymond and Kascak, Albert Glenn Research Center NASA/TM-2003-212592, E-14149, NAS 1.15:212592, AIAA Paper 2003-6110

Download or read book Magnetic Bearing Controller Improvements for High Speed Flywheel System written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-06-20 with total page 30 pages. Available in PDF, EPUB and Kindle. Book excerpt: A magnetic bearing control system for a high-speed flywheel system is described. The flywheel utilizes a five axis active magnetic bearing system, using eddy current sensors for position feedback to the bearing controller. Magnetic bearing controller features designed to improve flywheel operation and testing are described. Operational improvements include feed forward control to compensate for rotor imbalance, moving notch filtering to compensate for synchronous and harmonic rotational noise, and fixed notching to prevent rotor bending mode excitation. Testing improvements include adding safe gain, bearing current hold, bearing current zero, and excitation input features. Performance and testing improvements provided by these features are measured and discussed. Dever, Timothy P. and Brown, Gerald V. and Jansen, Ralph H. and Kascak, Peter E. and Provenza, Andrew J. Glenn Research Center NASA/TM-2003-212733, AIAA Paper 2003-12234, E-14258

Download or read book An Experimental Investigation Into the Temperature Profile of a Compliant Foil Air Bearing written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-06-21 with total page 36 pages. Available in PDF, EPUB and Kindle. Book excerpt: A series of tests was performed to determine the internal temperature profile in a compliant bump-type foil journal air bearing operating at room temperature under various speeds and load conditions. The temperature profile was collected by instrumenting a foil bearing with nine, type K thermocouples arranged in the center and along the bearing s edges in order to measure local temperatures and estimate thermal gradients in the axial and circumferential directions. To facilitate the measurement of maximum temperatures from viscous shearing in the air film, the thermocouples were tack welded to the backside of the bumps that were in direct contact with the top foil. The mating journal was coated with a high temperature solid lubricant that, together with the bearing, underwent high temperature start-stop cycles to produce a smooth, steady-state run-in surface. Tests were conducted at speeds from 20 to 50 krpm and loads ranging from 9 to 222 N. The results indicate that, over the conditions tested, both journal rotational speed and radial load are responsible for heat generation with speed playing a more significant role in the magnitude of the temperatures. The temperature distribution was nearly symmetric about the bearing center at 20 and 30 krpm but became slightly skewed toward one side at 40 and 50 krpm. Surprisingly, the maximum temperatures did not occur at the bearing edge where the minimum film thickness is expected but rather in the middle of the bearing where analytical investigations have predicted the air film to be much thicker. Thermal gradients were common during testing and were strongest in the axial direction from the middle of the bearing to its edges, reaching 3.78 8C/mm. The temperature profile indicated the circumferential thermal gradients were negligible. Radil, Kevin and Zeszotek, Michelle Glenn Research Center NASA/TM-2004-213100, ARL-TR-3200, E-14575

Download or read book Performance and Durability of High Temperature Foil Air Bearings for Oil Free Turbomachinery written by C. DellaCorte and published by . This book was released on 2000 with total page 22 pages. Available in PDF, EPUB and Kindle. Book excerpt: The performance and durability of advanced, high temperature foil air bearings are evaluated under a wide range (10-50 kPa) of loads at temperatures from 25 to 650 deg C. The bearings are made from uncoated nickel based superalloy foils. The foil surface experiences sliding contact with the shaft during initial start/stop operation. To reduce friction and wear, the solid lubricant coating, PS 304, is applied to the shaft by plasma spraying. PS304 is a NiCr based Cr2O3 coating with silver and barium fluoride/calcium fluoride solid lubricant additions. The results show that the bearings provide lives well in excess of 30,000 cycles under all of the conditions tested. Several bearings exhibited lives in excess of 100,000 cycles. Wear is a linear function of the bearing load. The excellent performance measured in this study suggests that these bearings and the PS 304 coating are well suited for advanced high temperature, oil-free turbomachinery applications.

Download or read book Performance and Durability of High Temperature Foil Air Bearing for Oil Free Turbomachinery written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-06-16 with total page 34 pages. Available in PDF, EPUB and Kindle. Book excerpt: The performance and durability of advanced, high temperature foil air bearings are evaluated under a wide range (10-50 kPa) of loads at temperatures from 25 to 650 C. The bearings are made from uncoated nickel based superalloy foils. The foil surface experiences sliding contact with the shaft during initial start/stop operation. To reduce friction and wear, the solid lubricant coating, PS304, is applied to the shaft by plasma spraying. PS304, is a NiCr based Cr2O3 coating with silver and barium fluoride/calcium fluoride solid lubricant additions. The results show that the bearings provide lives well in excess of 30,000 cycles under all of the conditions tested. Several bearings exhibited lives in excess of 100,000 cycles. Wear is a linear function of the bearing load. The excellent performance measured in this study suggests that these bearings and the PS304 coating are well suited for advanced high temperature, oil-free turbomachinery applications. DellaCorte, C. and Valco, M. J. and Radil, K. C. and Heshmat, H. Glenn Research Center NASA/TM-1999-209187, NAS 1.15:209187, E-11697

Download or read book High Performance Magnetic Bearings for Aero Applications written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-07-05 with total page 38 pages. Available in PDF, EPUB and Kindle. Book excerpt: Several previous annual reports were written and numerous papers published on the topics for this grant. That work is not repeated here in this final report. Only the work completed in the final year of the grant is presented in this final report. This final year effort concentrated on power loss measurements in magnetic bearing rotors. The effect of rotor power losses in magnetic bearings are very important for many applications. In some cases, these losses must be minimized to maximize the length of time the rotating machine can operate on a fixed energy or power supply. Examples include aircraft gas turbine engines, space devices, or energy storage flywheels. In other applications, the heating caused by the magnetic bearing must be removed. Excessive heating can be a significant problem in machines as diverse as large compressors, electric motors, textile spindles, and artificial heart pumps. Allaire, P. E. and Knospe, C. R. and Williams, R. D. and Lewis, D. W. and Barrett, L. E. and Maslen, E. H. and Humphris, R. R. Glenn Research Center NAG3-1334...

Download or read book A Passive Magnetic Bearing Flywheel written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-06-19 with total page 32 pages. Available in PDF, EPUB and Kindle. Book excerpt: A 100 percent passive magnetic bearing flywheel rig employing no active control components was designed, constructed, and tested. The suspension clothe rotor was provided by two sets of radial permanent magnetic bearings operating in the repulsive mode. The axial support was provided by jewel bearings on both ends of the rotor. The rig was successfully operated to speeds of 5500 rpm, which is 65 percent above the first critical speed of 3336 rpm. Operation was not continued beyond this point because of the excessive noise generated by the air impeller and because of inadequate containment in case of failure. Radial and axial stiffnesses of the permanent magnetic bearings were experimentally measured and then compared to finite element results. The natural damping of the rotor was measured and a damping coefficient was calculated. Siebert, Mark and Ebihara, Ben and Jansen, Ralph and Fusaro, Robert L. and Morales, Wilfredo and Kascak, Albert and Kenny, Andrew Glenn Research Center NASA/TM-2002-211159, E-13017, NAS 1.15:211159, IECEC2001-AT-89

Download or read book A Microprocessor Based Table Lookup Approach for Magnetic Bearing Linearization written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-07-24 with total page 28 pages. Available in PDF, EPUB and Kindle. Book excerpt: An approach for producing a linear transfer characteristic between force command and force output of a magnetic bearing actuator without flux biasing is presented. The approach is microprocessor based and uses a table lookup to generate drive signals for the magnetic bearing power driver. An experimental test setup used to demonstrate the feasibility of the approach is described, and test results are presented. The test setup contains bearing elements similar to those used in a laboratory model annular momentum control device. Groom, N. J. and Miller, J. B. Langley Research Center NASA-TP-1838, L-13969 RTOP 506-54-23-01