How do maglev trains work
Know about the basic properties of magnets. If you bring the north pole of one permanent magnet to the north pole of another magnet, they will repel. If one of the magnets connecting different poles is turned upside down, it is attracted. This is a simple principle found in maglev trains, which glide in the air over the rail for a short distance.
A maglev train, or magnet-enhanced train, is a transport system that uses the magnetic force of magnets on a large scale for levitation and propulsion and moves while controlled ‘without touching the ground’. This mode of transport is faster, quieter and jerkless than wheeled mass transit systems.
Magnetic suspension technology is based on three main subsystems: (How do Maglev Trains work) leverage, stabilization and acceleration. At the same time, there are two main technologies of magnetic suspension at the moment and one experimental, proven only on paper.
Trains based on electromagnetic suspension (EMS) technology use an electromagnetic field, the strength of which varies over time, to levitate. Also, the practical implementation of this system is similar to the operation of conventional railway transport. Here, a T-shaped rail track made of a conductor (mainly metal) is used, but the train, instead of wheels, uses a system of electromagnets – supports and guides.
The support and guide magnets are parallel to the ferromagnetic stator located on the sides of the T-track. The main disadvantage of EMS technology is the distance between the reference magnet and the stator, which is 15 millimeters and must be monitored and adjusted by specialized automated systems based on a number of factors, including the inconsistent nature of the electromagnetic interactions.
By the way, the levitation system works thanks to the batteries installed in the train, which are recharged by a linear generator built into the reference magnets. Thus, in the event of a stop, the train would be able to run on battery for a long time. Transrapid trains and, in particular, the Shanghai Maglev, were built on the basis of EMS technology.
EMS trains are driven and braked by a low-acceleration synchronous linear motor, represented by support magnets and a track on which the magnetic plane hovers. Broadly speaking, the motor system built into Webb is a conventional stator (the stationary part of a linear electric motor) positioned at the bottom of the Web, and the auxiliary electromagnets, in turn, act as an anchor for the electric motor.
Thus, instead of generating torque, the alternating current in the coils generates a magnetic field of excited waves, which makes the composition move contactless. Changing the strength and frequency of the alternating current allows you to adjust the traction and speed of the train. In this case, to slow down, you just need to change the direction of the magnetic field.
Electrodynamic Suspension Technology
In the case of electrodynamic suspension technology (EDS), levitation is achieved by the interaction of the magnetic field in the canvas and the field created by the superconducting magnets in the train. Japanese trains JR – Maglev were created on the basis of EDS technology.
Unlike EMS technology, which uses conventional electromagnets and coils to only conduct electricity when the power is in, superconducting electromagnets can conduct electricity even after the power source has been disconnected, such as in the event of a power outage. in situation. Cooling the coils in an EDS system can save a lot of energy. However, the cryogenic cooling system used to keep the coil cool can be expensive.
Advantages of EDS Technology
The main advantage of the EDS system is its high stability – with a slight decrease in the distance between the blade and the magnets, a repulsive force is generated, which returns the magnets to their original positions, plus, an increase in the distance reduces the repulsive force. and increases the force of attraction, which again leads to stabilization of the system. In this case, no electronics are required to control and adjust the distance between the train and the track.
A force sufficient to levitate the train is produced only at high speed. For this reason, an EDS train must be equipped with wheels that can run at low speeds (up to 100 km/h). Changes should also be made along the entire length of the track, as a technical fault can cause the train to stop at any point.
Disadvantages of EDS Technology
Another disadvantage of EDS is that at low speeds, a frictional force is generated in the web at the front and back of the repulsive magnets, which acts against them. This is one reason why JR-Maglev abandoned the repulsive system entirely and looked to the lateral leverage system.
It is also worth noting that strong magnetic fields in the passenger compartment require the installation of a magnetic shield. Without shielding, it is contraindicated for passengers with pacemakers or magnetic storage media to travel in such a vehicle.
Maglev Train Guinness Book of Records
At the moment, the first line in the list of the fastest magnetic levitation trains is occupied by the Japanese solution JR-Maglev MLX01, which on December 2, 2003 on the test track in Yamanashi managed to develop a record speed of 581 km. / NS. It is worth noting that the JR-Maglev MLX01 set several more records in the period from 1997 to 1999 – 531, 550, 552 km / h.
If you look at the closest competitors, then among them it is worth noting the Shanghai Maglev TransRapid SMT manufactured in Germany, which during tests in 2003 managed to develop a speed of 501 km / h, and its ancestor – TransRapid 07, which crossed Kia 436 km / h line back in 1988 year.
[How do Maglev Trains work | Maglev Trains Technology]