Background. A diesel locomotive must drive a significant number of units with different rated rotation speeds from a single diesel engine with minimal energy consumption. The mechanical and hydraulic drives currently in use demand high maintenance and specific oil quality, while electric drives are bulky and have lower efficiency. This study proposes the implementation of a contactless magnetic gear with a Halbach array in the auxiliary unit drive system, using the brake compressor as an example, to improve reliability and energy efficiency. At the same time these auxiliary drives, particularly the compressor drive, require a low gear ratio (u = 2...5) to to ensure the required rotation speed. While studies of such magnetic gears have been conducted, none of the existing studies have provided recommended relative values for the magnetic system geometric parameters that could be used to design a magnetic gear for a specified rated torque.
Materials and methods. Electromagnetic phenomena in the magnetic gear have been studied using a 2D field model based on Maxwell's equations. The calculations have been performed using the finite element method. To achieve a maximum compact design, multi-factor optimization of the geometric parameters of the magnetic gear with the Halbach array has been carried out according to Nelder-Mead method.
Results. Electromagnetic phenomena in magnetic gear have been studied. Their calculations have been performed. The optimal relative geometric parameters of the magnetic system have been determined. A comparison of the cost of active material has been conducted, revealing that the cost of a unit of torque in the gear with the Halbach array is 4,4 % lower.
Conclusions. As a result of the implementation of the Halbach array, the torque density has been increased by 39,4 %, allowing for a proportional reduction in the volume of the magnetic gear while maintaining the same output torque. The obtained optimal geometric parameters of the magnetic system can be used as recommendations to design magnetic gear with high torque density. A torque density of 330 kN·m/m³ has been achieved. Placing the Halbach array on the stator is the most effective configuration. It allows us to eliminate magnetic circuit, thereby reducing the volume of the magnetic gear without compromising the transmitted torque.