# Magnetic levitation technology application?

Using the principle of “same sex repelling, opposite sex attracting”, the magnet has the ability to resist gravity, so that the car body is completely off the track, suspended at a distance of about 1 cm from the track, and travels in the air, creating a nearly “zero height” space The miracle of flight. The world’s first maglev train demonstration operation line, Shanghai Maglev Train, will only take 7-8 minutes from Pudong Longyang Road Station to Pudong International Airport for more than 30 kilometers after completion. The Shanghai Maglev train is a “constantly conducting magnetic repulsion type” (referred to as “constantly conducting type”) maglev train. It is designed using the principle of “magnetic poles of the same name repel each other”. It is a repulsive force suspension system. The suspension electromagnets installed on the bogies on both sides of the train and the magnets laid on the track are used to generate the repulsive force under the action of the magnetic field. The vehicle floats up. That is to say, when the repulsive force of the magnetic force generated by the track and the gravity of the train are in a corresponding balance, the train will levitate.
Electromagnets are installed at the bottom of the train and on the top of the bogies on both sides, and a reaction plate and an induction steel plate are respectively set above the “I”-shaped rail and below the upper arm part to control the current of the electromagnet to maintain a gap of 1 cm between the electromagnet and the track. , so that the repulsive force between the bogie and the train and the gravity of the train balance each other, and the repulsive force of the magnet is used to float the train about 1 cm, so that the train is suspended on the track. This must precisely control the current to the electromagnet.
The driving principle of the suspended train is exactly the same as that of the synchronous linear motor. In layman’s terms, the alternating current flowing in the coils located on both sides of the track can turn the coils into electromagnets, which, due to their interaction with the electromagnets on the train, make the train move. To put it more straightforwardly, it is equivalent to the rotary motion between the rotor and the stator of the motor becoming the linear motion between the maglev train and the track. The maglev train is equivalent to the rotor of the motor, and the track is equivalent to the stator of the motor.
The N pole of the electromagnet at the head of the train is attracted by the S pole of the electromagnet installed on the track a little earlier, and repelled by the N pole of the electromagnet installed at a later point on the track. When the train moves forward, the direction of the current flowing in the coil is reversed, that is, the original S pole becomes the N pole, and the N pole becomes the S pole. Repeatedly, the train gallops forward.
Stability is controlled by a guide system. The “normally conducting magnetic repulsion” guiding system is to install a group of electromagnets specially used for guiding on the side of the train. When the train deviates from left to right, the guide electromagnet on the train interacts with the side of the guide rail to generate a repulsive force to restore the vehicle to its normal position. When the train is running on a curve or a ramp, the control system achieves the purpose of controlling the operation by controlling the current in the guide magnet.
The idea of ​​a “normally guided” maglev train was proposed by German engineer Hermann Kempel in 1922.
The working principle of the “normally guided” maglev train, track and motor is exactly the same. Just arrange the “rotor” of the motor on the train, and lay the “stator” of the motor on the track. Through the interaction between the “rotor” and “stator”, the electrical energy is converted into forward kinetic energy. We know that when the “stator” of the motor is energized, the “rotor” can be pushed to rotate through electromagnetic induction. When power is transmitted to the “stator” of the track, through electromagnetic induction, the train is pushed to move in a straight line just like the “rotor” of the motor.
The speed of Shanghai maglev train is 430 kilometers per hour. Only one train is allowed to run in a power supply area. There are isolation nets 25 meters on both sides of the track, and protective equipment on the upper and lower sides. The turning radius is 8,000 meters, and the naked eye is almost a straight line; the smallest radius is also 1,300 meters. Passengers will not experience discomfort. The most advanced isolation devices in the world are installed within 50 meters on both sides of the track.

Post time: Aug-06-2022