The Benefits of Magnetically Geared Drives and Motors

Quieter, cleaner and in the case of lightweight electric vehicles (LEVs) much smaller, today’s electric, hybrid and micromobility vehicles offer real potential to mitigate many of the problems associated with the UK’s noisy, congested and polluting traffic. What’s more, as the technology used in these vehicles evolves, they can bring even greater environmental and societal benefits.

A turning point in motor technology

Providing benefits across a range of applications, magnetic gears are highly efficient hybrid drive alternatives. They bring increased efficiency, reduced environmental impact and enhanced performance to a range of sectors, including urban air mobility (UAM), automotive, marine propulsion, aerospace, rail and LEV.

Magnetically geared motors are a significant improvement on traditional systems. By eradicating mechanical contact within the gears, they reduce the amount of energy lost to friction and thus operate far more efficiently, resulting in lower operational costs. The loss of friction also means that these motors generate much less heat, enabling them to work with minimal cooling requirements. In some applications, no cooling systems are needed at all. As a result, they can be much smaller and lighter and less complex.

The reduction in weight has a direct impact on the amount of energy needed to drive vehicles forward, while the smaller size means they are simpler in design, so less material is needed for their construction. This, in turn, lowers manufacturing costs. Indeed, the substantial decrease in motor size, together with the integration of magnetic gears within the motor structure, results in a design that can still match or outperform the power output of larger, conventional motors, despite its compactness. This attribute makes the magnetically geared motor ideal for applications where space is a premium, such as in electric vehicles, particularly LEVs.

Another benefit is that these motors maintain their efficiency even under partial loads, a clear advantage over traditional motors that can be less efficient when they are not operating at full capacity. This makes magnetically geared motors suitable for a wide range of operating conditions, especially where there are variable loads. Indeed, as the gear’s magnetic coupling can transmit high torque, it is also suitable for more heavy-duty applications. Furthermore, as there is no physical contact or wear-and-tear in the gearing mechanism, the need for maintenance is reduced and durability is extended.

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Figure 2: Micromobility

Finally, one of the most significant advantages of magnetically geared motors is that there is no need for a conventional gearbox. This further simplifies the design and reduces the number of components, which increases the motor’s reliability even more while reducing maintenance needs.

Tackling the traffic problem

The UK’s 40 million vehicles are responsible for a raft of major problems. According to the latest government figures, domestic transport alone was responsible for emitting 109 million tonnes of carbon dioxide equivalent in 2021, while 32% of nitrogen oxide emissions and 14% of particulate matter less than 2.5 micrometres across emissions came from transport. Aside from contributing to climate change and impacting air quality, the sheer volume of traffic has led to widespread sound pollution and a heavily congested road network. 

While not a panacea for these problems, the use of magnetic gears in urban transport is helping to mitigate them. When it comes to the key challenge of lowering emissions, EVs and LEVs fitted with magnetically geared motors offer not just a cleaner and greener alternative to traditional petrol and diesel vehicles, but one that is even more sustainable than standard electric vehicles. As they are more efficient, they don’t need to be charged as often and thus make less use of CO2-generating, fossil fuel based electricity. As a result, they contribute to the reduction of CO2 emissions and other forms of air pollution.

As traffic levels have increased, noise pollution has become a growing concern, particularly in densely populated urban areas with busy roads. While traditional combustion engines and even some electric motors can be quite noisy, the lack of a conventional gearbox means magnetic gears operate with extremely low noise levels, thus potentially improving the quality of life for residents in affected areas.

Even more beneficial, however, is their suitability for micromobility vehicles, like electric bikes and e-scooters. These small, lightweight vehicles are ideally suited to busy urban areas and their growing popularity is already beginning to have a significant impact on reducing congestion on the roads.

As hybrid power system alternatives become increasingly accessible and widely adopted, the reliability offered by magnetic gear systems will be a key attribute. Reliability is vital for commuters who depend on these vehicles to get around and magnetic gears offer not just consistent performance but less maintenance. Indeed, as urban areas develop their infrastructure to accommodate more sustainable modes of transport, the dependability and long-term cost efficiency of magnetic gears will become even more significant.

A bespoke approach

Magnomatics has successfully designed, manufactured and tested a 500kW wind generator based on its Pseudo Direct Drive (PDD) motors and generators technology. The specialised motor system was developed to overcome the torque limitations of traditional direct drive electric motors. With a gear system designed to emulate the characteristics of a direct drive, it delivers high torque at low speeds. It also benefits from a high-precision gear system that minimises backlash and increases efficiency.

The technology is particularly well-suited to offshore wind, where leading efficiency, low mass and size also low operation and maintenance costs lead to a significant reduction in levelized costs of energy compared to both state-of-the-art geared and direct drive options offered by industry leaders. To develop a more cost effective and safer production method to build the permanent magnet rotor, a major component of the PDD generator, Magnomatics embarked on the ROBOMAG project using robotic technologies to optimise the manufacturing process and drive big and safe productivity improvements.

Supported by OWGP, Magnomatics worked with the Advanced Manufacturing and Research Centre (AMRC) in Sheffield to actualise a solution. For the first step in the process, using 2D and 3D finite element electromagnetic software, magnet placement forces and torques for a two metre diameter magnet rotor for numerous magnet placement combinations were computed. This provided AMRC the maximum force and torque the robot arm would see and informed the design of an end-effector for the robot.

AMRC designed and made an end-effector to meet the requirement and using one of their automated cells, programmed a robot to demonstrate a solution that met the and reduced the time to pick and place a magnet on the rotor from 55 mins to 55 secs. This achievement not only reduces the time but it also provides a safer and flexible solution that lends itself to a wider range of magnet rotor diameters and massively reduced setup time with change rotor diameter.

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