Design and Optimization of a Magnetic Levitation Load Reduction Device for a Hydropower Unit

Abstract

The construction of hydropower stations has been expanding in China as a result of economic development and the improvement of people's lives. To save cost, the capacity of a single unit has been greatly increased, and many higher technical requirements have been presented for hydropower units, among which one of the key technologies is the thrust bearing. With the increase in single machine capacity, the pv value of the kinetic energy on the thrust bearing also increases, which will cause the bearing tile burning accident. Therefore, the thrust bearing needs to be designed to improve the bearing capacity. Instead of improving the traditional mechanical structure and using new materials, this paper proposes a levitation load reduction device for the thrust bearing to reduce the pv value of the kinetic energy on the thrust bearing. On the basis of kinetic energy analysis, the feasibility of the magnetic levitation load reduction device is analyzed. A repulsive maglev load reduction device suitable for hydropower units is designed; according to linear motor theory, a three-dimensional analytical model is established to analyze the levitation force, and an analytical calculation method is given. A finite element simulation model is built to study the effects of the primary electrical parameters, structural parameters, and material properties on electromagnetic forces, and the effect rules and the methods of optimal design are given. A small-scale prototype was developed, then tests were conducted to verify the feasibility and accuracy of the design and mechanism.

Keywords

• Hydropower unit
• magnetic levitation load reduction
• levitation force
• electromagnetic force
• linear motor