Carbon Sleeves

Digital Motors [or Permanent Magnet Motors] continue to be used in greater numbers to help our modern world cope with ever increasing demands of low carbon emissions and improved efficiency.

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Digital motors are based on permanent magnets which can spin at very high speeds – in excess of 200,000 rpm – in order to achieve the power outputs required. At these speeds the magnets, if not held in place, will actually throw themselves apart and destroy the motor itself. 

The best way to hold the magnets in place whilst maximising the motor’s performance is to use a thin nonconductive tube called a ‘digital motor sleeve’ which is usually made from advanced composite materials. 

The thickness and strength of these ‘digital motor sleeves’ is a major consideration at the design stage of any new motor. Advanced Composites Engineering Limited is a specialist in this field and has been continuing to develop its competence for over ten years whilst supplying some of the largest motor companies in the world. This includes extensive experience in material application, bespoke manufacturing techniques and specialist machines specifically designed by the Advanced Composites team.

These motors are used across the world in arenas that range from aerospace through military and industrial to consumer goods. Advanced Composites Engineering Limited is a must visit company if you find you need a ‘digital motor sleeve’ for your application as we can help with

  • Design for manufacture. 
  • Supply prototype parts.
  • Supply volume series production.
  • Insert rotor bodies into the digital motor sleeve prior to supply.

Digital motors have several key advantages over their conventional counterparts.

  1. High efficiency
  2. High power to weight ratio
  3. High power density
  4. Low noise
  5. Low maintenance
  6. Applicable to more onerous working conditions

Frequently Asked Questions

Carbon sleeves, also called digital motor sleeves, are thin non-conductive tubes that hold permanent magnets in place during high-speed rotation. They prevent magnets from flying apart at speeds exceeding 200,000 rpm, ensuring motor safety and performance in electric vehicles, aerospace, and industrial applications.

Carbon fibre sleeves offer superior strength-to-weight ratio, are non-conductive (preventing eddy current losses), and can withstand extreme centrifugal forces. They’re lighter than steel alternatives, improving motor efficiency and enabling higher power density in compact designs.

Carbon sleeves enable EV motors to run at higher speeds with better efficiency. The lightweight construction reduces energy consumption, while the non-conductive properties minimize electrical losses, directly contributing to extended driving range and improved battery life.

Key industries include automotive (electric vehicles), aerospace, military, industrial automation, robotics, wind energy, and consumer electronics.

Yes, carbon sleeves can be fully customized in terms of thickness, diameter, length, and material composition. Manufacturers offer design-for-manufacture services, prototyping, and volume production to meet specific motor requirements and performance targets.

Carbon sleeves are typically installed using pre-stressed fitting techniques or by sliding over prepared mandrels. Some manufacturers offer services to insert rotor bodies into sleeves before delivery, ensuring proper fit and eliminating installation challenges for customers.

High-quality carbon sleeves can handle speeds well over 200,000 rpm. The exact speed capability depends on sleeve thickness, diameter, and specific carbon fibre construction, with some specialized sleeves handling even higher rotational speeds in turbomachinery applications.

Carbon sleeves contribute to environmental sustainability by enabling more efficient electric motors, reducing energy consumption, and supporting the transition to electric vehicles. However, carbon fibre recycling remains a challenge that the industry is actively addressing.

Carbon sleeves are designed for the motor’s operational lifetime, typically lasting 10-15 years or more under normal operating conditions. Their excellent fatigue resistance and chemical stability ensure reliable long-term performance without degradation.

While carbon sleeves have higher upfront costs than steel alternatives, they provide better ROI through improved motor efficiency, reduced weight, and enhanced performance. The total cost of ownership is often lower due to energy savings and extended motor life.

The technology is ideally suited for use in cars, wagons, trucks, turbo chargers, aircraft, vacuums – indeed any application built around a central motor. Talk to our team of Composites experts today to see the benefits we could add to your next manufacturing project.
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