Transmission Characteristics of Axial Asynchronous Permanent Magnet Couplings

Abstract

In order to study the transmission characteristics of a new-type axial asynchronous permanent magnet coupling with 18 poles and 16 slots, the theoretical calculation method of the torque is obtained by theory of layered model firstly; then the distribution of 3D transient air gap field and the influence of different working parameters on torque characteristics are obtained; lastly, the 3D air gap field and torque in different working conditions are measured by the measure system of three-dimensional magnetic field and magnetic drive experimental platform, and the relationship curves between different working parameters and torque or efficiency are achieved. The results of simulation and experiment show that: the maximum magnetic flux density occurs at the magnetrotor, the magnetic flux density of the yoke iron attached to magnetic poles is also large; the axial flux density is the main component of air gap flux density; the axial flux density and the torque increase when the air gap thickness decreases;while the slip ratio and input speed increase respectively, the torque increases but the axial flux density decreases; the slip ratio increases slightly in a linear way firstly and then quickly with the increasing of the output torque, while the transmission efficiency firstly increases but then decreases slightly, particularly,at the 3% slip ratio the efficiency is up to the maximum; under the given 6% slip ratio the efficiency almost keeps about 94% when the input power increases, which verifies the law that the summation of slip and efficiency is constant 1; the efficiency keeps about 95% and the slip ratio is between 2% to 6% when the torque is between 26 and 48 N·m, by which excellent transmission characteristics and high efficiency could be proved in the heavy load working condition.