Motor brushes are essential components in electric motors, serving as sliding electrical contacts that allow current to flow into or out of the motor while maintaining conduction through friction. They are widely used in AC and DC generators, synchronous motors, battery-powered DC motors, crane motors with collector rings, welding machines, and more.
Early motor brushes were often made from copper wires. However, copper’s hardness easily scratched commutator segments, causing wear, short circuits, and high maintenance costs. With advances in materials, carbon brushes gradually replaced copper brushes as the mainstream. Made from carbon and binders, carbon brushes offer excellent lubricity and conductivity. Compared to copper, carbon brushes wear more evenly, cause less damage to the commutator, produce fewer sparks, and require only brush replacement for maintenance.
In modern rotating motors, especially miniature motors, carbon brushes are almost universally used. Some brushes include copper powder to enhance conductivity under low voltage and high current conditions, while higher carbon content suits high voltage, low current applications.
To further reduce sparking and improve commutation, high-resistance brushes were developed, composed of carbon mixed with copper powder. These brushes smooth current transitions, reducing commutator stress and sparking.
The way a brush contacts the commutator directly affects motor performance and lifespan:
Copper brushes usually contact tangentially and support only single-direction rotation;
Carbon brushes are softer, allowing radial contact and reversible rotor operation.
The brush contact area is not a fine line but a rectangular patch, typically spanning 2.5 commutator segments. This ensures smooth current transfer during commutation, improving operational stability.
Carbon brushes are widely applied in home appliances, massage devices, wearable electronics, automotive micro-motors, and small robots. Properly designed brushes reduce noise, extend service life, and provide stable current in compact spaces.
In automotive micro-motors (e.g., side mirror adjustment motors, window lifter motors) and small household appliances, carbon brushes’ durability and low-maintenance characteristics offer clear advantages.
As a company with 20 years of experience in miniature motor R&D and manufacturing, Guandong Lihua Mechatronics Co., Ltd specializes in 1V–36V, 0.05W–100W output power, and 5.4mm–45mm diameter DC miniature motors. The company has 400 employees, including 8 senior engineers, and has provided over 20,000 customized motor solutions.
On the production side, Lihua Motor features an 80% automated production line, including automatic winding machines, rotor assembly machines, and full inspection systems, ensuring brush and commutator stability and consistency. The company also holds international certifications including CE, ISO 9001, IATF 16949, ROHS, REACH, SGS, CCC, and UL, demonstrating its commitment to quality and compliance with global standards.
Although small, motor brushes are crucial for miniature motor performance and lifespan. The transition from copper to carbon brushes reflects significant progress in motor technology. With strong R&D capabilities and strict quality systems, Guandong Lihua Mechatronics Co., Ltd continues to provide high-performance, long-life miniature motor solutions across consumer electronics, automotive, medical, and household appliance industries.
For reliable miniature motor solutions, Lihua Motor is a trusted partner.
