Magnetic bearing

About: Magnetic bearing is a research topic. Over the lifetime, 8259 publications have been published within this topic receiving 74331 citations.

Magnetic bearings : theory, design, and application to rotating machinery

Abstract: and Survey.- Principle of Active Magnetic Suspension.- Hardware Components.- Actuators.- Losses in Magnetic Bearings.- Design Criteria and Limiting Characteristics.- Dynamics of the Rigid Rotor.- Control of the Rigid Rotor in AMBs.- Digital Control.- Dynamics of Flexible Rotors.- Identification.- Control of Flexible Rotors.- Touch-down Bearings.- Dynamics and Control Issues for Fault Tolerance.- Self#x2013 Sensing Magnetic Bearings.- Self#x2013 Bearing Motors.- Micro Magnetic Bearings.- Safety and Reliability Aspects.

A novel high-performance magnetic gear

Abstract: Mechanical gearboxes are used extensively to match the operating speed of prime-movers to the requirements of their loads. Although, high system torque densities can be achieved, gear lubrication and cooling are often required, whilst noise, vibration and reliability can be significant issues. The paper describes the design and performance of a magnetic gear, which employs rare-earth magnets, which simulation studies have shown to have a transmitted torque density exceeding 100 kNm/m/sup 3/.

Rotordynamics prediction in engineering

Abstract: Part 1 Characteristics of rotor elements: disc shaft bearings and seals mass unbalance. Part 2 Simple models - basic phenomena: determination of the model symmetric rotor dissymmetric rotor instability damped rotors. Part 3 Rotor equations - solutions of equations: finite elements of rotor elements equations for monorotors equations for coaxial multirotors solution of equations computer program. Part 4 Towards industrial applications: pseudo-modal method influence of modeling natural frequencies - bearing stiffness diagram transmissibility dual rotor. Part 5 Industrial applications: steam compressor high pressure centrifugal compressor low pressure centrifugal compressor centrifugal compressor fitted with active magnetic bearings power gas turbine industrial steam turbine textile machine spindle jet engine. Part 6 Transient motions: equations and solutions speed of rotation law behaviour of a simple rotor experimental and theoretical results for a three disc rotor behaviour of an industrial rotor. Part 7 Torsion: determination from statics of the minimum shaft radius branched systems in torsion analysis of a branched system in torsion industrial electric motor-centrifugal compressor unit. Part 8 Miscellaneous topics: dissymmetric shaft equations with periodic coefficients axial torque influence.

Superconductor bearings, flywheels and transportation

Abstract: This paper describes the present status of high temperature superconductors (HTS) and of bulk superconducting magnet devices, their use in bearings, in flywheel energy storage systems (FESS) and linear transport magnetic levitation (Maglev) systems. We report and review the concepts of multi-seeded REBCO bulk superconductor fabrication. The multi-grain bulks increase the averaged trapped magnetic flux density up to 40% compared to single-grain assembly in large-scale applications. HTS magnetic bearings with permanent magnet (PM) excitation were studied and scaled up to maximum forces of 10 kN axially and 4.5 kN radially. We examine the technology of the high-gradient magnetic bearing concept and verify it experimentally. A large HTS bearing is tested for stabilizing a 600 kg rotor of a 5 kWh/250 kW flywheel system. The flywheel rotor tests show the requirement for additional damping. Our compact flywheel system is compared with similar HTS–FESS projects. A small-scale compact YBCO bearing with in situ Stirling cryocooler is constructed and investigated for mobile applications. Next we show a successfully developed modular linear Maglev system for magnetic train operation. Each module levitates 0.25t at 10 mm distance during one-day operation without refilling LN2. More than 30 vacuum cryostats containing multi-seeded YBCO blocks are fabricated and are tested now in Germany, China and Brazil.

Halbach permanent magnet machines and applications: a review

Abstract: Permanent magnet brushless machines employing multipole Halbach magnetised rotors are being developed for various applications, since they offer a number of attractive features. Alternative Halbach machine topologies are reviewed, and the realisation of Halbach magnetised magnets from pre-magnetised sintered rare earth magnet segments (which approximate the Halbach magnetisation distribution and thereby compromise their performance), and as bonded isotropic and anisotropic NdFeB ring magnets (which are subsequently impulse magnetised with a Halbach field distribution), is considered. Radial- and axial-field, slotted and slotless, rotary and linear (tubular and planar), and spherical Halbach magnetised brushless machines are described, and potential applications, including a motor/generator for a high-speed flywheel peak power buffer, high-performance linear and rotary servo motors, and passive magnetic bearings are considered.