Motor Core Loss Explained: Silicon Steel Sheet, Stator Lamination, etc.

Core loss, also called iron loss, is one of the three main types of energy loss in a motor, along with copper loss and windage loss. The performance of the motor core is influenced by several key factors: silicon steel sheet, stator lamination, motor design, and motor speed. The role played by silicon steel sheets in determining the motor’s efficiency is significant.

1. Material

Manufacturers typically laminate cold-rolled silicon steel to produce motor cores. Engineers use iron loss as a key indicator of material performance and define the grade according to its loss value.For example, Baosteel’s non-oriented grade B35A250 exhibits a core loss of 2.5 W/kg under 1.5 T at 50 Hz. Lower grade numbers correspond to reduced losses, improved performance, and higher cost. Therefore, selecting high-quality electrical steel is essential for minimizing core loss and optimizing overall motor efficiency.

Silicon steel sheet

2. Lamination Process

The lamination process directly affects core loss. Common methods include self-locking rivet points, welding, gluing, and clamping strips. Different processes lead to different loss values. For instance, in glued lamination, the eddy current loss caused by inter-layer conduction is effectively eliminated. High-end motors often use glued cores for improved efficiency. Best has years of experience producing glued cores and is one of the few domestic manufacturers capable of mass-producing bonded cores, showcasing their expertise in managing silicon steel sheets effectively.

3. Motor Design

The design of the motor also impacts core loss. Factors such as the number of motor teeth, the arrangement of magnets, material selection, and winding parameters all influence the overall efficiency. Careful design helps reduce unnecessary losses in the core, especially if silicon steel sheets are utilized smartly.

4. Motor Speed

Motor speed directly affects the frequency, calculated as speed × number of pole pairs / 60. Eddy current loss is proportional to the square of this frequency, so higher-speed motors experience greater core loss if the silicon steel sheet thickness or grade remains the same. This is why high-speed motors commonly use ultra-thin sheets, such as 0.1mm super silicon steel sheets, to combat enhanced losses.

Conclusion: Selecting high-quality silicon steel sheet, combined with optimized lamination processes and careful motor design, is crucial for reducing core loss and improving motor efficiency.