The Working Principle And Application Of Linear Induction Motors

The supplier of linear induction motors motors is a mechanical device that converts electrical energy directly into linear motion. Since 1917 appeared the first cylindrical linear motor, has been nearly 100 years of development. According to the different structure type, linear motor can be divided into flat type linear motor and cylindrical linear motor.

The principle of linear induction motors

Linear induction motors is divided into flat-shaped single-sided, flat-shaped double-sided, cylindrical, short stator and short rotor mode, the power can be single-phase or three-phase. To single-sided linear induction motors, for example, it consists of stator and moving body composition. The stator is also called the primary, which is formed by stacking the electric steel sheet of the cogging, and the groove is embedded in the groove. The moving body is also called a secondary conductor, usually a metal plate made of copper or aluminum. There is a certain distance between the stator and the moving body, that is, the air gap. When the winding is connected to the single-phase or three-phase alternating current, the magnetic flux density B expressed by the following equation is generated: B = B0cos (ωt - πx / τ), ω = 2πf, x The distance on the stator surface, Pole distance. The moment is the half-wavelength of the magnetic flux density, which is equal to half the length of the cycle, the magnetic flux density is a function of distance x is also a function of distance x. This kind of t and x as a function of the magnetic flux density called traveling wave magnetic field, which is rotating the induction motors with the rotating magnetic field is the same principle. As described above, the magnetic flux generated in the stator after the AC input is applied, and the eddy current is induced on the metal plate of the movable body according to Lenz's law. Let the induced voltage of the eddy current be E, the inductance L and the resistance R on the metal plate, the eddy current on the metal plate is I = E / z, the eddy current and the magnetic flux density will produce a continuous thrust F The There are positive and negative thrust, but the thrust is much larger than the negative thrust, the force acting on the body is mainly positive thrust, which is the working principle of linear induction motors. Linear induction motors drive device can use the inverter. The output frequency of the inverter can be controlled under the action of the control signal, which can be controlled by logic or closed loop. The inverter outputs a different frequency and the resulting thrust will change accordingly. As the frequency of the two coils of the stator is different, the synchronous change of the traveling wave magnetic field is caused, so that the thrust of the motor is changed from 0 to the maximum.

Application of Linear Induction Motors

It is widely used in machine tools, pumping units, electromagnetic pumps, electromagnetic valves, vacuum circuit breakers, etc., because of the advantages of simple structure, reliable operation, fast response and high precision, which is driven by linear motor drive. Need for linear drive in the field.