Originally published in Electric & Hybrid Marine Technology.

Today’s boat engines, gallon for gallon, emit more pollutants than vehicles on the road. As a result, the US Environmental Protection Agency introduced requirements for catalytic converters on inboard and stern-drive boats beginning in 2011. Many manufactures of personal watercraft initially switched to outboard propulsion and are now looking to electric motors as the next step.

Converting a boat from gasoline to electric is not as straightforward as dropping in a battery and motor from a car, though. Since boat drag increases with speed, the energy to move a boat through water is far greater than that required for an equivalent electric vehicle.

Arnold offers Arnon silicon steel, laminated magnets and carbon-fiber windings for electric motors that require higher efficiencies. Arnold’s non-grain oriented electrical steel (NGOES) is optimized by thickness and finish. Arnon silicon steel is frequently used for laminations in high speed, high-efficiency motors and generators. Whereas common laminations use thicknesses between 0.356mm and 0.813mm, Arnon 5 and Arnon 7 are thinner – at 0.127mm and 0.178mm respectively.

Arnon electrical steel has been shown to be particularly advantageous for higher-frequency motors and generators above 400Hz. In these designs, the thinner material offsets the less efficient effects of increased eddy currents and subsequent heat build-up. Using thin laminations of Arnon produces a more efficient unit and frees up design constraints by making it possible to fully enclose the motor without external cooling, for example.

Arnold’s Wraptite composite sleeves offer a superior design alternative to metallic solutions, particularly in applications that require high rotational speed or the containment of high centrifugal forces – such as high-speed motors and generators. Wraptite has a low density and high strength-to-weight ratio, as well as greater containment stresses for sleeves of the same thickness, leading to increased rotor speeds. Reduction or elimination of eddy currents in the containment sleeves reduces hear generation and improves efficiency.

Wraptite composite materials include carbon fiber, Zylon fiber and glass fiber composites using a range of epoxy cyanate ester and BMI-based (bismaleimide) resin systems. The material can operate at temperatures up to 170° C.

When entering a partnership, the first step is to decide what the end goal is, and how best to accomplish it. Perhaps a world-class supplier is struggling with pricing, quality or delivery from its existing supply chain. In that case, Arnold can be an alternative source for either an individual motor component or the complete motor system, having complete control over the supply chain. For example, Arnold sources SmCo (samarium cobalt) magnets from its plant in Switzerland, where all pressing and sintering is done in-house, coupled with a partnership with a rare earth mine to ensure the supply of quality raw materials.

Developing a marine electric motor takes specialized expertise in electric motor design. Arnold can collaborate at whatever step of the process makes the most sense. It offers everything from specialist information on permanent magnet technology, to sources components from an extensive selection of Arnold-operated global resources, all the way up to a complete motor design. Arnold provides quick-turn design, rapid prototyping and testing, using one of its technology centers around the world.

About Arnold Magnetic Technologies

Based in Rochester, NY with an operating history of more than 125 years, Arnold is a leading global manufacturer of engineered solutions for a wide range of specialty applications and end-markets, including aerospace and defense, general industrial, motorsport, oil and gas, medical, and energy. From its Technology Center and manufacturing facilities located in the United States, the United Kingdom, Switzerland, and China, the company produces engineered magnetic assemblies in addition to high-performance permanent magnets, precision foil products, and highly loaded composites that are mission critical in motors, generators, sensors, and other systems and components. Based on its long-term relationships, the company has built a diverse and blue-chip customer base totaling more than 2,000 clients worldwide. For more information on Arnold, visit https://www.arnoldmagnetics.com.   

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Originally published in Electric & Hybrid Marine Technology.

Electric transportation poses pressing design and manufacturing challenges – one of which is its high-power requirements. The electrification of all transportation would require more power than a standard electrical grid could provide on top of current demands. Permanent magnet motors have increasingly become the motor of choice in various applications as they benefit from superior energy efficiency and power-to-weight ratio. The efficiency of these motors is especially advantageous in battery-powered systems. The automotive and marine industries have embraced these motors in powertrains due to their impressive power density, efficiency and compact size. Their brushless design offers improved reliability and longevity over traditional induction motor designs.

Material choices

When considering materials for high-performance PM applications, neodymium iron boron (NdFeB) and samarium cobalt (SmCo) are widely used due to their high magnetic strength. However, they differ in several key aspects that can influence their suitability for various applications.

NdFeB magnets exhibit higher magnetic flux than SmCo magnets, which means they can deliver more magnetic force. This makes such magnets suitable for applications that require higher torque output with lighter weights, such as electric vehicles and wind turbines. However, NdFeB magnets have a lower resistance to high temperatures and are more prone to corrosion, which may require additional thermal management or protective coating in certain applications.

On the other hand, SmCo magnets offer superior temperature stability and corrosion resistance. For example, Arnold Magnetic Technologies’ Recoma 35E SmCo magnet materials, the most power-dense samarium cobalt magnet available, are engineered for the most demanding environments including high speed (in excess of 100,000 rpm), high temperature (150-250° C) and highly corrosive environments.

Unlike neodymium (Nd) magnets, which need high levels of rare dysprosium (Dy) to function at moderate temperatures, SmCo magnets use materials that are more widely available and are stable at temperatures well above the Curie point of NdFeB. This makes SmCo pricing more stable and less prone to rare earth market changes.

When there are supply concerns, it’s crucial to source domestically when possible. Companies such as Arnold Magnetic Technologies offer a broad-based source of supply for samarium cobalt magnets’ materials, including samarium cobalt made in the USA. Plus, Arnold’s recent partnership with Cyclic Materials provides another supply source for these critical resources. Arnold and Cyclic Materials are creating the world’s first circular supply chain for rare earth materials through reclamation.

In applications where high power density is a must, efficiency must be maximized. Precision-rolled thin metals, L-type laminated magnets and more help customers achieve higher efficient and power gains in their motor and transformer designs. Arnold has played a pivotal role in the electrification of transportation since the invention of the electric train. Today the company works with its customers to pioneer electric propulsion systems for space, air, watercraft, motorsport vehicles and heavy equipment.

About Arnold Magnetic Technologies

Based in Rochester, NY with an operating history of more than 125 years, Arnold is a leading global manufacturer of engineered solutions for a wide range of specialty applications and end-markets, including aerospace and defense, general industrial, motorsport, oil and gas, medical, and energy. From its Technology Center and manufacturing facilities located in the United States, the United Kingdom, Switzerland, and China, the company produces engineered magnetic assemblies in addition to high-performance permanent magnets, precision foil products, and highly loaded composites that are mission critical in motors, generators, sensors, and other systems and components. Based on its long-term relationships, the company has built a diverse and blue-chip customer base totaling more than 2,000 clients worldwide. For more information on Arnold, visit https://www.arnoldmagnetics.com.   

The post Magnetic Materials for Electric Transportation appeared first on Arnold Magnetic Technologies.