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Since a train may stop at any location, due to equipment problems for instance, the entire track must be able to support both low-speed and high-speed operation. Another downside is that the repulsive system naturally creates a field in the track in front and to the rear of the lift magnets, which act against the magnets and create a form of drag.
The test model levitated at speeds above 22 mph (35 km/h), but Richard Post believes that, on real tracks, levitation could be achieved at "as little as 1 to 2 mph (1.6 to 3.2 km/h)". [citation needed] Below the transition speed the magnetic drag increases with vehicle speed; above the transition speed, the magnetic drag decreases with speed. [4]
Visualization of Eddy Currents Induction [3] In its most basic form — the single-element ECT probe — a coil of conductive wire is excited with an alternating electric current. This wire coil produces an alternating magnetic field around itself. The magnetic field oscillates at the same frequency as the current running through the coil.
Essentially all types of magnets have been used to generate lift for magnetic levitation; permanent magnets, electromagnets, ferromagnetism, diamagnetism, superconducting magnets, and magnetism due to induced currents in conductors. To calculate the amount of lift, a magnetic pressure can be defined.
To reduce average power requirements, often the electromagnetic suspension is used only to stabilise the levitation, and the static lift against gravity is provided by a secondary permanent magnet system, often pulled towards a relatively inexpensive soft ferromagnetic material such as iron or steel.
Disk electromagnetic brakes are used on vehicles such as trains, and power tools such as circular saws, to stop the blade quickly when the power is turned off.A disk eddy current brake consists of a conductive non-ferromagnetic metal disc attached to the axle of the vehicle's wheel, with an electromagnet located with its poles on each side of the disk, so the magnetic field passes through the ...
A magnetic bearing. A magnetic bearing is a type of bearing that supports a load using magnetic levitation.Magnetic bearings support moving parts without physical contact. For instance, they are able to levitate a rotating shaft and permit relative motion with very low friction and no mechanical w
Depending on requirements, the orientation of the magnetic field may need to be changed 90 degrees to inspect for indications that cannot be detected from steps 3 to 5. The most common way to change magnetic field orientation is to use a "coil shot". In Fig 1 a 36-inch coil can be seen then steps 4, 5, and 6 are repeated.