Design And Key Technology Research Of Permanent Magnet Coupling

The fans, pumps account for a large proportion of the total energy consumption by motors. At present,the adjustment method of its system is fall behind, and energy wastes seriously. Permanent magnet coupling can realize no mechanical connection transmission between the motor and fans, pumps well. It not only achieves the performance of adjustable-speed, but also has the characteristics that vibration isolation, soft start, soft stop and adapt to the harsh environment and so on. In this paper, the design and key technology of permanent magnet coupling are carried out as follows:Firstly, according to analytic theory of the eddy current field, the formula of eddy current loss in the copper disk was deduced. The relationship between slip and torque was calculated using MATLAB program. Aiming at the structure type of permanent magnet coupling, the structural dimensions of prototype was designed, and its structure diagram was protracted. According to parameters of the prototype model, the 3D simulation model of permanent magnet coupling established using ANSOFT software. Through analysis of 3D transient field, the distribution of flux density and current density was obtained, and the relation curve between slip and loss, torque, axial force under different air gaps was gained.Secondly, temperature field was carried out using finite element software ANSYS WORKBENCH based on the structural characteristic of permanent magnet coupling. Through the actual operating conditions, the heat source, conductivity coefficient and heat transfer coefficient was determined, and temperature rise of permanent magnet and permanent magnet disk under each slip and different air gaps was got by calculation. In condition that the slip below 250r/min, the permanent magnet can run for long-term meets the standard of heat load generally.And then, stress field of the permanent magnet disk, which is the most easily to deformation in all components of permanent magnet coupling, was proceeded. To ensure that the permanent magnet coupling can work regularly and reliably, the stress and deformation of the permanent magnet at the maximum load were verified to fit the assessment criteria.Finally, the prototype of permanent magnet coupling was manufactured according to the draft, and the testing program was established. By comparing the torque data with test and calculation data under four air-gaps at 0-250r/min, the calculation value got by program has certain errors, and the finite element calculation was feasible with small error. Ensuring that the permanent magnet fits the application required and the permanent magnet coupling works in permissible range, the error between test of temperature rise and calculation value was less, which verified the accuracy of the calculation method of temperature rise.