This article is about magnetic levitation. For trains based on this effect, see Maglev train. Magnetic levitation, maglev, or magnetic suspension is a method by which an object is suspended above another object with no support other than magnetic fields. The electromagnetic force is used to counteract the effects of the gravitational force. Transrapid Shanghai Maglev Train stopping at terminus Longyang Road station Transrapid Shanghai Maglev Train Inside the Shanghai Transrapid maglev Inside the Shanghai Transrapid maglev VIP section Magnetic levitation transport, or maglev, is a form of transportation that suspends, guides and propels vehicles (especially trains) using electromagnetic force. ...
Image File history File links Download high resolution version (550x700, 153 KB)A small (~6mm) piece of pyrolytic graphite levitating over a permanent neodymium magnet array (5mm cubes on a piece of steel). ...
Image File history File links Download high resolution version (550x700, 153 KB)A small (~6mm) piece of pyrolytic graphite levitating over a permanent neodymium magnet array (5mm cubes on a piece of steel). ...
Pyrolytic carbon is a material similar to graphite, but with some covalent bonding between its graphene sheets. ...
A cubical magnet levitating over a superconducting material (this is known as the Meissner effect) Levitation (from Latin levare, to raise) is the process by which an object is suspended against gravity, in a stable position, by a force without physical contact. ...
Magnetic field lines shown by iron filings In physics, the space surrounding moving electric charges, changing electric fields and magnetic dipoles contains a magnetic field. ...
In physics, the electromagnetic force is the force that the electromagnetic field exerts on electrically charged particles. ...
This article covers the physics of gravitation. ...
Stability
Earnshaw's theorem proved conclusively that it is not possible to levitate stably using only static, macroscopic, "classical" electromagnetic fields. The forces acting on an object in any combination of gravitational, electrostatic, and magnetostatic fields will make the object's position unstable. However, several possibilities exist to make levitation viable, by violating the assumptions of the theorem — for example, the use of electronic stabilization or diamagnetic materials. Earnshaws theorem states that a collection of point charges cannot be maintained in a stable stationary equilibrium configuration solely by the electrostatic interaction of the charges. ...
Classical electrodynamics (or classical electromagnetism) is a theory of electromagnetism that was developed over the course of the 19th century, most prominently by James Clerk Maxwell. ...
A gravitational field is a model used within physics to explain how gravity exists in the universe. ...
In physics, an electric field or E-field is an effect produced by an electric charge that exerts a force on charged objects in its vicinity. ...
Brief explanation of magnetostatics Magnetostatics is the study of static magnetic fields. ...
Diamagnetism is a very weak form of magnetism that is only exhibited in the presence of an external magnetic field. ...
Methods There are several methods to obtain magnetic levitation. The primary ones used in maglev trains are servo-stabilized electromagnetic suspension (EMS), electrodynamic suspension (EDS), and (in the future) Inductrack. Transrapid Shanghai Maglev Train stopping at terminus Longyang Road station Transrapid Shanghai Maglev Train Inside the Shanghai Transrapid maglev Inside the Shanghai Transrapid maglev VIP section Magnetic levitation transport, or maglev, is a form of transportation that suspends, guides and propels vehicles (especially trains) using electromagnetic force. ...
Inductrack is a completely passive, fail-safe magnetic levitation system, using only unpowered loops of wire in the track and permanent magnets (arranged into Halbach arrays) on the vehicle to achieve magnetic levitation. ...
Mechanical constraint If two magnets are mechanically constrained along a single vertical axis (a piece of string, for example), and arranged to repel each other strongly, this will act to levitate one of the magnets above the other. This is considered pseudo-levitation. For other uses, see Magnet (disambiguation). ...
Direct diamagnetic levitation A substance which is diamagnetic repels a magnetic field. Earnshaw's theorem does not apply to diamagnets; they behave in the opposite manner of a typical magnet due to their relative permeability of μr < 1. All materials have diamagnetic properties, but the effect is very weak, and usually overcome by the object's paramagnetic or ferromagnetic properties, which act in the opposite manner. Any material in which the diamagnetic component is strongest will be repelled by a magnet, though this force is not usually very large. Diamagnetic levitation can be used to levitate very light pieces of pyrolytic graphite or bismuth above a moderately strong permanent magnet. As water is predominantly diamagnetic, this technique has been used to levitate water droplets and even live animals, such as a grasshopper and a frog; however, the magnetic fields required for this are very high, typically in the range of 16 teslas, and therefore create significant problems if ferromagnetic materials are nearby. Image File history File links Frog_diamagnetic_levitation. ...
Image File history File links Frog_diamagnetic_levitation. ...
A millimetre (American spelling: millimeter, symbol mm) is an SI unit of length that is equal to one thousandth of a metre. ...
DIAMETER is a computer networking protocol for AAA (Authentication, Authorization and Accounting). ...
Bore may refer to: A wave in a river caused by an incoming tide - see tidal bore The diameter of a pipe or tube, or the caliber of a gun The diameter of a cylinder and piston in a piston engine (See also: Stroke) A person who is boring The...
A Bitter electromagnet or Bitter solenoid is a type of electromagnet made of metal plates and insulating spacers stacked in a helix configuration, rather than coils of wire. ...
SI unit. ...
Diamagnetism is a very weak form of magnetism that is only exhibited in the presence of an external magnetic field. ...
Earnshaws theorem states that a collection of point charges cannot be maintained in a stable stationary equilibrium configuration solely by the electrostatic interaction of the charges. ...
In electromagnetism, permeability is the degree of magnetization of a material that responds linearly to an applied magnetic field. ...
Paramagnetism is the tendency of the atomic magnetic dipoles, due to quantum-mechanical spin, in a material that is otherwise non-magnetic to align with an external magnetic field. ...
Ferromagnetism is a phenomenon by which a material can exhibit a spontaneous magnetization, and is one of the strongest forms of magnetism. ...
Pyrolytic carbon is a material similar to graphite, but with some covalent bonding between its graphene sheets. ...
General Name, Symbol, Number bismuth, Bi, 83 Chemical series poor metals Group, Period, Block 15, 6, p Appearance lustrous reddish white Atomic mass 208. ...
Impact from a water drop causes an upward rebound jet surrounded by circular capillary waves. ...
SI unit. ...
Ferromagnetism is a phenomenon by which a material can exhibit a spontaneous magnetization, and is one of the strongest forms of magnetism. ...
The minimum criteria for diamagnetic levitation is  , where:
Assuming ideal conditions along the z-direction of solenoid magnet: In physics and electrical engineering, the magnetic susceptibility is the degree of magnetization of a material in response to an applied magnetic field. ...
For other uses, see Density (disambiguation). ...
In physics, gravitational acceleration is the acceleration of an object caused by the force of gravity from another object. ...
This article is about the unit of length. ...
This article is about the unit of time. ...
This article is in need of attention. ...
Magnetic field lines shown by iron filings In physics, the space surrounding moving electric charges, changing electric fields and magnetic dipoles contains a magnetic field. ...
See also: Diamagnetic levitation in the Diamagnetism article. Impact from a water drop causes an upward rebound jet surrounded by circular capillary waves. ...
For other uses, see Graphite (disambiguation). ...
Levitating pyrolytic carbon Diamagnetism is a form of magnetism that is only exhibited by a substance in the presence of an externally applied magnetic field. ...
Levitating pyrolytic carbon Diamagnetism is a form of magnetism that is only exhibited by a substance in the presence of an externally applied magnetic field. ...
Superconductors Superconductors may be considered perfect diamagnets (μr = 0), completely expelling magnetic fields due to the Meissner effect. The levitation of the magnet is stabilized due to flux pinning within the superconductor. This principle is exploited by EDS (electrodynamic suspension) magnetic levitation trains. Superconductivity is a phenomenon occurring in certain materials at low temperatures, characterised by the complete absence of electrical resistance and the damping of the interior magnetic field (the Meissner effect. ...
Diagram of the Meissner effect. ...
Flux pinning is the phenomenon where a magnets lines of force (called flux) become trapped or pinned inside a superconducting material. ...
Transrapid at the Emsland test facility Transrapid maglev in Shanghai Magnetic levitation transport, or maglev, is a radically new form of transportation that suspends, guides and propels vehicles via electro-magnetic energy. ...
In trains where the weight of the large electromagnet is a major design issue (a very strong magnetic field is required to levitate a massive train) superconductors are used for the electromagnet, since they can produce a stronger magnetic field for the same weight.
Diamagnetically-stabilized levitation A permagnet can be stably suspended by various configurations of strong permanent magnets and strong diamagnets. When using superconducting magnets, the levitation of a permanent magnet can even be stabilized by the small diamagnetism of water in human fingers.[1] Iron filings in a magnetic field generated by a bar magnet A magnet is an object that has a magnetic field. ...
Rotational stabilization -
A magnet can be stabilized by spinning it in a field created by a ring of other magnets. However, it will only remain stable until the rate of precession slows below a critical threshold — the region of stability is quite narrow both spatially and in the required rate of precession. The first discovery of this principle was by Roy Harrigan, a Vermont inventor who patented a levitation device in 1983.[2] Several devices using rotational stabilization (such as the popular Levitron toy) have been developed citing this patent. Non-commercial devices have been created for university research laboratories, generally using magnets too powerful for safe public interaction. Spin stabilized magnetic levitation is a phenomenon originally discovered through invention by Vermont inventor Roy M. Harrigan in the late 1970s. ...
Precession of a gyroscope Precession refers to a change in the direction of the axis of a rotating object. ...
A critic (derived from the ancient Greek word krites meaning a judge) is a person who offers a value judgement or an interpretation. ...
Look up Threshold in Wiktionary, the free dictionary. ...
The Levitron is a device consisting of a permanently magnetized top that can levitate above a magnetic base as long as it spins at the right speed. ...
Servo stabilization Dynamically-stabilized magnetic levitation can be achieved by measuring the position and trajectory of the magnet being levitated, and continuously adjusting the local magnetic field to compensate for its motion. Look up position in Wiktionary, the free dictionary. ...
Mathematically the term trajectory refers to the ordered set of states which are assumed by a dynamical system over time (see e. ...
This is the principle in place behind common tabletop levitation demonstrations, which use a beam of light to measure the position and velocity of an object. In simple systems, an electromagnet is above the object being levitated upwards; the electromagnet is turned off whenever the object gets too close, and turned back on when it falls further away. Such a simple system is not very robust; much more complicated and effective measurement, magnetic, and control systems are, however, possible.
This is also the principle upon which electromagnetic suspension (EMS) magnetic levitation trains are based: The train wraps around the track, and is pulled upwards from below. The servo controls keep it at a constant distance from the track. In Maglev Trains Electromagnetic suspension (EMS) in Maglev trains is a system whereby a powered electromagnet maintains a train at a constant distance from a track. ...
Transrapid at the Emsland test facility Transrapid maglev in Shanghai Magnetic levitation transport, or maglev, is a radically new form of transportation that suspends, guides and propels vehicles via electro-magnetic energy. ...
Look up servo in Wiktionary, the free dictionary. ...
Rotating conductors beneath magnets If one rotates a base made of an electrical conductor beneath a magnet, a current will be induced in the conductor that will repel the magnet. At a sufficiently high rate of rotation of the conductive base, the suspended magnet will levitate. An especially technologically-interesting case of this comes when one uses a Halbach array instead of a single pole permanent magnet. A Halbach array is a special arrangement of permanent magnets which augments the magnetic field on one side of the device while cancelling the field to near zero on the other side. ...
Halbach arrays are also well-suited to magnetic levitation of gyroscopes and electric motor and generator spindles. A gyroscope For other uses, see Gyroscope (disambiguation). ...
For other kinds of motors, see motor. ...
This article is about machines that produce electricity. ...
The word spindle might (or might not) have several meanings: A spindle (shrub), a poisonous shrub or small tree of the genus Euonymus. ...
High-frequency oscillating electromagnetic fields A conductor can be levitated above an electromagnet with a high frequency alternating current flowing through it. This causes any regular conductor to behave like a diamagnet, due to the eddy currents generated in the conductor. Since the eddy currents create their own fields which oppose the magnetic field, the conductive object is repelled from the electromagnet. In science and engineering, conductors, such as a electrical connector, are materials that readily conduct electric current through electrical conduction. ...
High frequency (HF) radio frequencies are between 3 and 30 MHz. ...
City lights viewed in a motion blurred exposure. ...
As the circular plate moves down through a small region of constant magnetic field directed into the page, eddy currents are induced in the plate. ...
This effect requires high frequencies and non-ferromagnetic conductive materials like aluminium or copper, as the ferromagnetic ones are also strongly attracted to the electromagnet. The effect can be used for stunts such as levitating a telephone book by concealing an aluminium plate within it. “Aluminum†redirects here. ...
For other uses, see Copper (disambiguation). ...
Translational Halbach arrays and Inductrack Moving Halbach arrays over a conductive loop will generate a current in the loop, which will in turn create an opposing magnetic field. At some critical velocity the induced magnetic field is strong enough to induce levitation over a series of such loops. The Halbach arrays can be placed in a stable configuration and installed in, for example, a train cart. A Halbach array is a special arrangement of permanent magnets which augments the magnetic field on one side of the device while cancelling the field to near zero on the other side. ...
The Inductrack maglev train system avoids the problems inherent in both the EMS and EDS systems, especially failsafe suspension. It uses only permanent magnets — in a Halbach array mounted in the train cart — and unpowered conductive loops installed in the track to provide levitation. The only requirement for levitation is that the train must already be moving at a few kilometers per hour (roughly the same as walking speed) to keep levitating. Inductrack is a completely passive, fail-safe magnetic levitation system, using only unpowered loops of wire in the track and permanent magnets (arranged into Halbach arrays) on the vehicle to achieve magnetic levitation. ...
The term Fail-safe is used to describe: A device which, if (or when) it fails, fails in a way that will cause no harm or at least a minimum of harm to other devices or danger to personnel. ...
A Halbach array is a special arrangement of permanent magnets which augments the magnetic field on one side of the device while cancelling the field to near zero on the other side. ...
A cart is a vehicle or device, using two wheels and normally one horse, designed for transport. ...
Kilometre per hour (American spelling: kilometer per hour) is a unit of both speed (scalar) and velocity (vector). ...
The electric current induced in the loop conductors in the track drains energy from the motion of the train (called "magnetic drag"), but efficiency is still good, and no active electronics or cryogenics for superconductors are needed. Cryogenics is a branch of physics (or engineering) that studies the production of very low temperatures (below –150 °C, –238 °F or 123 K) and the behavior of materials at those temperatures. ...
See also A magnetic bearing is a bearing which supports a load using magnetic levitation. ...
Electrostatic levitation is the process of using an electric field to lift a charged object and counteract the effects of gravity. ...
A force diagram showing how vertical and lateral stabilization occurs in a vertically oriented optical trap. ...
Acoustic levitation is a method for suspending matter in a fluid by using acoustic radiation pressure from intense sound waves in the fluid. ...
Aerodynamic levitation apparatus: a spherical sample is floated on a gas stream which flows through the conical nozzle. ...
The Levitron is a device consisting of a permanently magnetized top that can levitate above a magnetic base as long as it spins at the right speed. ...
For the use of unimodal in mathematics and statistics, see Unimodal function Unimodal or SkyTran is a proposal by Douglas Malewicki for a 160km/h (100mph) personal rapid transit system. ...
A linear motor is essentially a multi-phase alternating current (AC) electric motor that has had its stator unrolled so that instead of producing a torque (rotation) it produces a linear force along its length. ...
A linear motor is essentially a multi-phase alternating current (AC) electric motor that has had its stator unrolled so that instead of producing a torque (rotation) it produces a linear force along its length. ...
a train of the Nagahori Tsurumi-ryokuchi Line The Nagahori Tsurumi-ryokuchi Line ) is one of the lines of Osaka Municipal Subway ), the underground rapid transit system in Osaka City, Japan. ...
References battymanddodoloyuo Year 1983 (MCMLXXXIII) was a common year starting on Saturday (link displays the 1983 Gregorian calendar). ...
is the 123rd day of the year (124th in leap years) in the Gregorian calendar. ...
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is the rate of change of the magnetic field along the vertical axis
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