Smaller Package – More Power: Unlocking High Performance Motors with SMCs

 By now you may have read a blog article or two where we’ve discussed the many advantages of soft magnetic composites (SMCs) on the performance and energy efficiency of new electric motor designs. Often overlooked is the opportunity to reduce both the size and weight of the device, reducing the space needed to house the motor and enhancing the efficiency of the overall design. These two key functional aspects of motor design and end use are of critical importance in electric vehicles, robotics, consumer electronics, home appliances, and drone and aerospace applications. So, is SMC technology the answer to satisfying these demanding specifications without compromising performance?

How SMCs Enable More Compact and Efficient Motors

Unique Design Opportunities

Before diving into SMCs and their potential benefits, let’s take a step back and review traditional motor designs. The vast majority of traditional motors are radial flux designs that utilize stamped steel laminations that are either glued, welded, or interlocked together to form the stator assembly. While a proven design, this solution does have some shortcomings. For instance,

• The need to stuff copper windings thru a narrow stator slot results in an end turn that wastes copper in the magnetic circuit.
• Laminations are magnetically most efficient only in the plane of the laminations.
• Material utilization ranges from 50% to 80%.
• In the case of radial flux motors, SMCs are not typically a direct 1:1 replacement Often, stator redesign is necessary to account for material performance differences.

Now let’s consider a SMC motor stator. It starts with a precise weight of insulated powder that is compacted via advanced powder metallurgy (PM) methods into a net shape stator. The unique morphology of the powders allows for 3D magnetic flux paths, enabling advanced motor designs such as the yokeless axial flux motor, the trapezoidal radial flux motor, and transverse flux designs. Let’s take a closer look at each of these concepts:

• Yokeless Axial Flux Motors: Ultra compact designs eliminate the need for a yoke or back iron. Each individual stator is compacted and assembled into a suitable non-magnetic retaining structure. This unique architecture enables two sets of magnets (top and bottom), thus significantly increasing the output torque while effecting reduced size and weight. Wheel hub motors are a prime example of these dual benefits providing greater control and performance.

• Trapezoidal Radial Flux Motors: This radial flux design is a radical rethinking of the traditional radial design, demonstrating improved torque density with a smaller footprint. It’s ideal for any land, sea or air e-mobility application.

• Novel Topologies: Included in this broad designation are transverse flux designs and even unique, forward-thinking combinations of radial, axial, and transverse designs that have not yet been envisioned. SMC provides solutions without limitations imposed by traditional laminations, freeing motor designers from the bonds of conventional thinking.

Reducing Weight Without Sacrificing Performance

• Minimized Material Waste: SMCs enable compact designs, requiring less raw material. Because SMCs are based on net shape manufacturing capabilities of PM, material efficiency is often greater than 97%.*
• No Laminations Needed: SMCs eliminate the 2D limitation of laminations and the scrap associated with stamping round stators from rectangular sheets of electrical steel. However, let’s not rush to throw away laminations! Horizon Technology has developed unique Lamination + SMC hybrid structures that improve permeability, providing 3D shape and flux capability with reduced electrical losses. Now you really can have the best of both worlds!
• Lower Inertia, Higher Power Density: Lightweight motors improve energy efficiency, response times, and overall system performance.
• Lower Core Losses Mean Higher Performance: SMC stators show reduced eddy current losses because of the inherent fine particles used in their manufacture. These lower eddy current losses, leading to lower total losses—particularly in those motors with operating frequencies greater than 200Hz.

*97% of input material is used in the finished product.

Clearing a Path to Greener Motors

• Reduced Energy Use: PM components have been shown to reduce the total energy required to produce a finished part by 17%. With the ever-increasing costs of energy, this is key to a more sustainable future.

• Easier Recyclability: The SMC stator can be easily crushed, allowing for simplified recovery of copper and magnet materials. This reduces the amount of scrap generated from cradle to grave, supporting sustainable manufacturing.
• Lower Resource Consumption: Smaller, lighter motors mean less copper, reduced cost to manufacture, reduced energy cost during operation, and reduced recycling cost. The net result is reduced environmental impact without compromising performance.

With SMCs, Horizon Technology has brought to the market a future-ready solution that transforms motor design. Motors can now be smaller, lighter, more efficient, and sustainable, helping businesses stay ahead of market demands while embracing eco-friendly practices. Whether you're looking to optimize an existing motor design or explore cutting-edge innovations, we’re here to help you unlock the full potential of SMC technology.

Interested in learning more? Our experts can help you discover how SMCs can transform your applications for a more efficient and sustainable future.