The maglev train uses the principle of "same-sex repelling, opposite-sex attracting" to make the magnets have 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 near "zero height". "The miracle of space flight.
After the completion of the world's first maglev train demonstration line, Shanghai Maglev Train, it will take only 6 to 7 minutes for more than 30 kilometers from Pudong Longyang Road Station to Pudong International Airport.
The Shanghai maglev train is a "normally conducting magnetic attraction" (referred to as "constantly conducting type") maglev train. It is designed based on the principle of "opposites attract". It is a suction suspension system. It uses the suspension electromagnets installed on the bogies on both sides of the train and the magnets laid on the track. The suction generated by the magnetic field causes the vehicle to float.
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 and the current of the electromagnet is controlled to maintain a gap of 1 cm between the electromagnet and the track. , to balance the attraction between the bogie and the train and the gravity of the train, and use the magnet attraction to float the train by 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, and the train starts due to its interaction with the electromagnets on the train.
The N pole of the electromagnet at the head of the train is attracted by the S pole of the electromagnet installed on the front track, 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. The cycle alternates and the train runs forward.
The stability is controlled by the guidance system. The "normally conducting magnetic attraction" 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 "constantly guided" maglev train was proposed by German engineer Hermann Kempel in 1922.
The working principle of the "normally guided" maglev train, track, and the 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 forwarding 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 the 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. The Shanghai line will eventually extend to Hangzhou. And directly serve the Expo.
