PCB (printed circuit board) motors represent a significant technological innovation, combining PCB and wedge magnets to create compact, lightweight, and highly efficient new motors. As technology advances, PCB motors will demonstrate their value in more fields.
What is a PCB Motor?
A PCB motor is a kind of axial flux motor that integrates circuits with mechanical structures. Typically, PCB material is used to make the stator, while wedge magnets form the rotor, achieving motor movement through the current drive. Components on the printed circuit board (conductors, resistors, capacitors, etc.) are closely connected to the motor, forming a complete circuit system. When current flows through these components, they generate magnetic fields that drive the motor’s rotational or linear motion.
Advantages of PCB Motors
| Performance: The reduction of stator hysteresis and eddy current losses improves motor efficiency. PCB motors run more quietly and also increase motor reliability by eliminating potential problems associated with copper windings and insulation in traditional motors.
| Small size and lightweight: Unlike traditional motors, PCB motors don’t use iron cores and copper windings. Copper coils are directly etched onto the PCB stator, using 66% less copper than traditional wound stators.
| Thermal Stability: In traditional motors, the copper windings, iron core, and insulation materials each have different thermal expansion coefficients. During temperature changes, the motor components expand and contract at different rates. This can create thermal stress, potentially causing cracks in the insulation. In contrast, a PCB stator has similar thermal expansion coefficients, allowing for uniform expansion and contraction during thermal cycles without generating thermal stress.
| Product Consistency: The manufacturing process of traditional motors involves forming and insulating copper coils, with a low level of automation. This makes it difficult to ensure that every coil is well-insulated and that there are no gaps between coils. The PCB manufacturing process, on the other hand, is highly automated, allowing for quantitative control during production, which improves product consistency.
| Long Lifespan: The absence of cogging torque extends the lifespan of the drive system. In general, the lifespan of a PCB stator is ten times longer than that of a traditional motor stator.
| High Integration: PCB stator technology significantly reduces the size of the stator, allowing the motor itself to become more compact. Sensors and other devices can also be directly placed on the PCB, increasing integration and simplifying assembly.
The Role of Wedge Magnets in PCB Motors
When current flows through the stator of a PCB motor, it generates a force in the magnetic field, causing the magnet rotor to start rotating. The motor’s speed depends on the magnitude of the current and the strength of the magnetic field.
However, the role of magnets in PCB motors goes beyond this. For example, magnets with high magnetic energy product can significantly increase the motor’s output power, thereby reducing energy consumption and improving overall efficiency. This high efficiency not only helps with energy conservation and emissions reduction but also reduces heat loss during motor operation, thereby extending the motor’s lifespan.
Tech Infomation of Wedge Magnets in PCB Motors
| Magnet Selection: The magnets used in PCB motors are typically wedge-shaped neodymium magnets. They can also be customized according to customer requirements.
| Magnet Grade: The higher the magnet grade, the stronger the magnetic field. In theory, a stronger magnetic field leads to higher electromagnetic conversion efficiency, greater torque generation, and faster response times.
| High-Temperature Stability: The magnets used in PCB motors often have medium to high coercivity. For example, magnets used in electric vehicle drive motors tend to have high magnetic energy product and high coercivity, such as 45UH, 48UH, 50UH, 42EH, and 45EH. When manufacturing magnets, a mature grain boundary diffusion process is required.
| Magnetic Flux Consistency: Variations in magnetic flux consistency can cause motor vibrations and reduced power, and negatively impact the motor’s overall performance. Therefore, motors generally require strict magnetic flux consistency, with tolerances often set at 5%, 3%, or even 2%. Factors affecting magnetic flux consistency include the uniformity of residual magnetism, tolerance consistency, chamfer consistency, and coating uniformity.
| Magnet Assembling: Segmented bonded magnets are widely used in the motor industry to improve the sectional insulation of the magnets, reducing eddy current loss during motor operation. In some cases, magnets may have an epoxy coating on the surface to enhance insulation.
| Adaptability: Wedge magnets are predominantly used in PCB motors. Since tightly arranged magnets require control over cumulative gaps and the fitting tightness of the magnets, adaptability is a crucial factor to consider.
Size Reference
| Material | Wedge Neodymium Magnet |
| Grade | 42H |
| Size | OR30mm x IR18mm x H4mm |
| Tolerance | ±0.05mm |
| Coating | NiCuNi |
| Max Operating Temperature | 120℃ |
Applications of PCB Motors
The innovative applications of printed circuit board (PCB) motors are also noteworthy. They are widely used in fields such as consumer electronics and robotics, helping to drive development in these industries.
| Transportation: The elimination of the traditional stator core in PCB motors significantly reduces weight, and the removal of core losses can boost efficiency to levels unattainable by other methods. This makes PCB motors suitable for various propulsion and auxiliary applications in the automotive, aerospace, power sports, and marine industries.
| Consumer Products: The removal of the stator core in PCB motors effectively eliminates cogging and torque ripple, significantly reducing noise. This makes them ideal for vacuum cleaners, dishwashers, and household appliances.
Wedge Magnets Provider
At Tengye, we’re thrilled to be early participants in your new projects. Our passion for magnets extends from material selection and design optimization to providing magnetic solutions. We hope to bring our knowledge and experience to the forefront by actively engaging in your upcoming projects. Work with our magnet experts to get the right magnet solution.
Image Source: Couragemagnet & Ietresearch & Link.springer & Pcbstator & Researchgate & Semanticscholar
