A 14 Tesla 15-cm bore superconductive magnet.
14-Tesla 15-cm bore superconductive magnet and test results
SUPERCONDUCTING MAGNET↗
SEARCH · Engineering Papers
Results for “magnet test”
Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.
Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.
A magnetic suspension system with a large angular range
The paper describes a small-scale laboratory system, called the Large-Angle Magnetic Suspension Test Fixture (LAMSTF), constructed at NASA Langley Research Center in order to explore and develop technology required for the magnetic suspension of objects over large ranges of orientation. The LAMSTF hardware comprises five electromagnets in a circular arrangement, each driven from a separate bipolar power amplifier. The suspended element is a cylindrical axially magnetized permanent magnet core, within an aluminum tube. The element, which is 'levitated' by repulsive forces, is stabilized in five degrees-of-freedom, with rotation about the cylinder axis not controlled. The controller accommodates the changes in magnetic coupling between the electromagnets and the suspended element by real-time adaptation of a decoupling matrix. The paper presents performance measurements demonstrating that the major design objective of the 360 deg rotation was accomplished.
Britcher, Colin P.↗
Implementation of a decoupled controller for a magnetic suspension system using electromagnets mounted in a planar array
An implementation of a decoupled, single-input/single-output control approach for a large angle magnetic suspension test fixture is described. Numerical and experimental results are presented. The experimental system is a laboratory model large gap magnetic suspension system which provides five degree-of-freedom control of a cylindrical suspended element. The suspended element contains a core composed of permanent magnet material and is levitated above five electromagnets mounted in a planar array.
Cox, D. E.↗
Overview of NASA GRC Stirling Technology Development
The Stirling Radioisotope Generator (SRG) is currently being developed by Lockheed Martin Astronautics (LMA) under contract to the Depar1ment of Energy (DOE). The generator will be a high efficiency electric power source for NASA Space Science missions with the capability to operate in the vacuum of deep space or in an atmosphere such as on the surface of Mars. High system efficiency is obtained through the use of free-piston Stirling power conversion technology. Power output of the generator will be greater than 100 watts at the beginning of life with the decline in power being largely due to the decay of the plutonium heat source. In suppOl1 of the DOE SRG project, the NASA Glenn Research Center (GRC) has established a near-term technology effort to provide some of the critical data to ensure a successful transition to flight for what will be the first dynamic power system used in space. Initially, a limited number of technical areas were selected for the GRC effort, however this is now being expanded to more thoroughly cover a range of technical issues. The tasks include in-house testing of Stirling convertors and controllers, materials evaluation and heater head life assessment, structural dynamics, electromagnetic interference, organics evaluation, and reliability analysis. Most of these high-level tasks have several subtasks within. There is also an advanced technology effort that is complementary near-term technology effort. Many of the tests make use of the 55-We Technology Demonstration Convel10r (TDC). There have been multiple controller tests to support the LMA flight controller design effort. Preparation is continuing for a thermal/vacuum system demonstration. A pair of flight prototype TDC's have recently been placed on an extended test with unattended, continuous operation. Heater head life assessment efforts continue, with the material data being refined and the analysis moving toward the system perspective. Long-term magnet aging tests are continuing to characterize any possible aging in the strength or demagnetization resistance of the permanent magnets used in the linear alternator. In a parallel effort, higher performance magnets are also being evaluated. A reliability effort is being initiated that will help to guide the development activities with an increased focus on the necessary components and subsystems. Some other disciplines that are active in the GRC technology effort include structural dynamics, linear alternator analysis, EMI/EMC, controls, and mechanical design evaluation. This paper will provide an overview of some of the GRC technical efforts, including the current status, and a description of future efforts.
Schreiber, Jeffrey↗
High efficiency magnetic bearings
Research activities concerning high efficiency permanent magnet plus electromagnet (PM/EM) pancake magnetic bearings at the University of Maryland are reported. A description of the construction and working of the magnetic bearing is provided. Next, parameters needed to describe the bearing are explained. Then, methods developed for the design and testing of magnetic bearings are summarized. Finally, a new magnetic bearing which allows active torque control in the off axes directions is discussed.
Studer, Philip A.↗
Test particle acceleration in turbulent reconnecting magnetic fields
The effect of turbulence on particle acceleration in a MHD field was investigated by computing test particle trajectories in turbulent MHD reconnecting fields, including reconnection simulations at different magnetic Reynolds numbers. The dynamics of individual particles were investigated making it possible to examine the acceleration mechanism in great detail. It was found that turbulence influences the acceleration in two ways. It enhances the reconnection electric field while producing a stochastic electric field that gives rise to momentum diffusion; and it produces magnetic 'bubbles' and other irregularities that can temporarily trap test particles in the strong reconnection electric field for times comparable to the magnetofluid characteristic time.
Ambrosiano, John↗
Design and testing of a coaxial linear magnetic spring with integral linear motor
The design of a coaxial linear magnetic spring which incorporates a linear motor to control axial motion and overcome system damping is presented, and the results of static and dynamic tests are reported. The system has nominal stiffness 25,000 N/m and is designed to oscillate a 900-g component over a 4.6-mm stroke in a Stirling-cycle cryogenic refrigerator being developed for long-service (5-10-yr) space applications (Stolfi et al., 1983). Mosaics of 10 radially magnetized high-coercivity SmCO5 segments enclosed in Ti cans are employed, and the device is found to have quality factor 70-100, corresponding to energy-storage efficiency 91-94 percent. Drawings, diagrams, and graphs are provided.
Patt, P. J.↗
GRMHD Simulations of Jet Formation with RAISHIN
We have developed a new three dimensional general relativistic magnetohydrodynamic (GRMHD) code, RAISHIN, using a conservative, high-resolution shock capturing scheme. Numerical fluxes are calculated using the Harten, Lax, & van Leer (HLL) approximate Riemann solver scheme. The flux-interpolated, constrained transport scheme is used to maintain a divergence-free magnetic field. We describe code performance on some test problems in both special and general relativity. Our new GRMHD code has proven to be accurate to second order and has successfully passed several numerical test problems including highly relativistic and magnetized tests in both special and general relativity. We have performed several simulations of non-rotating and rotating black hole systems with a geometrically thin accretion disk. The simulations show the formation of jets driven by the Lorentz force and the gas pressure. It appears that the rotating black hole creates an additional faster, and more collimated outflow inside a broader, slower outflow that is also generated by the rotating accretion disk around a non-rotating black hole. The kinematic jet structure could thus be a sensitive function of black hole rotation.
Mizuno, Y.↗
High Speed Testing of a High Efficiency Concentric Magnetic Gear
This presentation presents measurements of the efficiency of NASA's 2nd magnetic gear prototype. A detailed discussion of the test rig used to make these measurements was presented, including a thorough uncertainty analysis. The reported uncertainties are 95% confidence intervals that include the effects of temperature and parasitic loads. The prototype's response was measured at output speeds between 124 rpm and 744 rpm for a controlled output torque of 10 Nm (8% of the prototype's maximum torque). After correcting for tare losses, the prototype's efficiency was found to decrease from 90.0% to 83.0% as speed increased. If the efficiency is extrapolated to a typical operating condition (85% of maximum torque) using the good assumption that energy loss is approximately independent of the transmitted torque,the expected efficiency would be 99.0% to 98.4%, which exceeds the state of the art for these speeds.
Scheidler, Justin↗
Preliminary Measurements of Partial Discharge Inception Voltage Degradation with Constant Temperature Aging of Magnet Wire Twisted Pairs for Electric Aircraft Motors
Electric aircraft require high reliability electric motors to meet the stringent safety standards of the aviation industry. Motor winding insulation lifetime and reliability models for electric aircraft applications are needed to enable design of high reliability and high-performance electric motors for aviation applications. Three primary stresses effect the lifetime of motor winding insulation: thermochemical, mechanical, and electrical. This paper presents preliminary experiments on twisted pairs of magnet wire targeting understanding the thermo-chemical degradation of motor winding insulation through constant temperature thermal aging. Three types of magnet wire twisted pairs where tested: polyimide insulated magnet wire, epoxy coated polyimide insulated magnet wire, and epoxy potted polyimide magnet wire. The degradation of the samples over time at temperature was tracked using partial discharge inception voltage measurements. These initial experiments were used for development of procedures and expertise in partial discharge testing and thermo-chemical aging to inform future testing. The preliminary nature of these experiments should be noted when viewing the results. Lessons learned from the experiments are documented.
Thomas Tallerico↗
Levitation Technology in International Space Station Research
The International Space Station (ISS) is a unique multidisciplinary orbiting laboratory for science and technology research, enabling discoveries that benefit life on Earth and exploration of the universe. ISS facilities for containerless sample processing in Materials Science experiments include levitation devices with specimen positioning control while reducing containment vessel contamination. For example, ESA's EML (ElectroMagnetic Levitator), is used for melting and solidification of conductive metals, alloys, or semiconductors in ultra-high vacuum, or in high-purity gaseous atmospheres. Sample heating and positioning are accomplished through electromagnetic fields generated by a coil system. EML applications cover investigation of solidification and microstructural formation, evaluation of thermophysical properties of highly reactive metals (whose properties can be very sensitive to contamination), and examination of undercooled liquid metals to understand metastable phase convection and influence convection on structural changes. MSL utilization includes development of novel light-weight, high-performance materials. Another facility, JAXA's ELF (Electrostatic Levitation Furnace), is used to perform high temperature melting while avoiding chemical reactions with crucibles by levitating a sample through Coulomb force. ELF is capable of measuring density, surface tension, and viscosity of samples at high temperatures. One of the initial ELF investigations, Interfacial Energy-1, is aimed at clarification of interfacial phenomena between molten steels and oxide melts with industrial applications in control processes for liquid mixing. In addition to these Materials Science facilities, other ISS investigations that involve levitation employ it for biological research. For example, NASA's "Magnetic 3D Culturing and Bioprinting" investigation uses magnetic levitation for three-dimensional culturing and positioning of magnetized cells to generate spheroid assemblies for biomedical applications. Levitation is also used as a modeled microgravity ground analog in the NASA OsteoOmics ISS investigation, which tests whether magnetic levitation accurately simulates microgravity conditions by studying gravitational regulation of osteoblast and osteoclast genomics and metabolism. Elucidating the cellular mechanisms of bone loss in microgravity contributes to the understanding of bone loss in medical disorders on Earth, which may lead to development of preventive or therapeutic countermeasures. Thus, the ISS state-of-the-art laboratory offers various levitation capability platforms with applications for innovative research in Materials and Life Sciences disciplines, with benefits for humanity.
Guinart-Ramirez, Y.↗
Magnetic control assembly qualification model
Fabrication and testing of the magnetic control assembly (MCA) are summarized. The MCA was designed as an add-on unit for certain existing components of the Nimbus and ERTS attitude control system. The MCA system consists of three orthogonal electromagnets; a magnetometer probe capable of sensing external fields in the X, Y, and Z axes; and the control electronics. An operational description of the system is given along with all major drawings and photographs. Manufacturing and inspection procedures are outlined and a chronological list of events is included with the fabrication summary.
Shen, R. C.↗
Overview of NASA GRC Stirling Technology Development
The Stirling Radioisotope Generator (SRG) is currently being developed by Lockheed Martin Astronautics (LMA) under contract to the Department of Energy (DOE). The generator will be a high efficiency electric power source for NASA Space Science missions with the ability to operate in vacuum or in an atmosphere such as on Mars. High efficiency is obtained through the use of free-piston Stirling power conversion. Power output will be greater than 100 watts at the beginning of life with the decline in power largely due to the decay of the plutonium heat source. In support of the DOE SRG project, the NASA Glenn Research Center (GRC) has established a technology effort to provide data to ensure a successful transition to flight for what will be the first dynamic power system in space. Initially, a limited number of areas were selected for the effort, however this is now being expanded to more thoroughly cover key technical issues. There is also an advanced technology effort that is complementary to the near-term technology effort. Many of the tests use the 55-We Technology Demonstration Convertor (TDC). There have been multiple controller tests to support the LMA flight controller design effort. Preparation is continuing for a thermal/vacuum system demonstration. A pair of flight prototype TDC s have been placed on continuous operation. Heater head life assessment continues, with the material data being refined and the analysis moving toward the system perspective. Magnet aging tests continue to characterize any possible aging in the strength or demagnetization resistance of the magnets in the linear alternator. A reliability effort has been initiated to help guide the development activities with focus on the key components and subsystems. This paper will provide an overview of some of the GRC technical efforts, including the status, and a description of future efforts.
Schreiber, Jeffrey G.↗
Magnetic Field Apparatus (MFA) Hardware Test
The objectives of this study are threefold: (1) Provide insight into water delivery in microgravity and determine optimal germination paper wetting for subsequent seed germination in microgravity; (2) Observe the behavior of water exposed to a strong localized magnetic field in microgravity; and (3) Simulate the flow of fixative (using water) through the hardware. The Magnetic Field Apparatus (MFA) is a new piece of hardware slated to fly on the Space Shuttle in early 2001. MFA is designed to expose plant tissue to magnets in a microgravity environment, deliver water to the plant tissue, record photographic images of plant tissue, and deliver fixative to the plant tissue.
Anderson, Ken↗
Experimental feasibility study of the application of magnetic suspension techniques to large-scale aerodynamic test facilities
Based on the premises that (1) magnetic suspension techniques can play a useful role in large-scale aerodynamic testing and (2) superconductor technology offers the only practical hope for building large-scale magnetic suspensions, an all-superconductor three-component magnetic suspension and balance facility was built as a prototype and was tested successfully. Quantitative extrapolations of design and performance characteristics of this prototype system to larger systems compatible with existing and planned high Reynolds number facilities have been made and show that this experimental technique should be particularly attractive when used in conjunction with large cryogenic wind tunnels.
Zapata, R. N.↗
Superconducting Magnets Used as a Magnetic Bumper/Tether System
Development of new materials for superconducting trapped field (permanent) magnets, and a continuation of tests on a magnetic bumper/tether for spacecraft docking is reported.
Weinstein, Roy↗
A Deposited Magnetic Thermometer for Temperatures Below 0.1 Kelvin
Magnetic thermometers are less sensitive to self-heating due to rf noise than are traditional resistive thermometers. This makes them appealing at temperatures well below 0.1 Kelvin in the operating range of many space-flight detectors. We have built and tested a magnetic thermometer which is deposited directly onto a substrate. This device, which uses the temperature dependence of iron-doped palladium s magnetic susceptibility, includes self-shielding deposited coils surrounding a sputtered palladium layer. It is read out using a SQUID to achieve high resolution. Its small size and very good heat-sinking should eventually make it useful for the temperature control of space flight detector arrays, in particular those already using SQUID readouts. The design and test results for this device are discussed.
Tuttle, J. G.↗
A Deposited Magnetic Thermometer for Temperatures below 0.1 Kelvin
Magnetic thermometers are much less sensitive to self-heating due to rf noise than are traditional resistive thermometers. This makes them appealing at temperatures well below 0.1 Kelvin in the operating range of many space-flight detectors. We have developed and tested a magnetic thermometer which is deposited directly onto a substrate. This device, which uses the temperature dependence of iron-doped palladium's magnetic susceptibility, includes self-shielding deposited coils surrounding a sputtered palladium layer. It is read out using a SQUID to achieve high resolution. Its small size and perfect heat sinking should make it useful for the temperature control of space flight detector arrays, in particular those already using SQUID readouts. The design and test results for this device are discussed.
Tuttle, J. G.↗