28 n ELECTRIC MOTORS November/December 2025 www.drivesncontrols.com What are the limits to motor efficiency? In the continuing battle to decarbonise, while maintaining profitability, every improvement in industrial energy efficiency creates a ripple effect that extends well beyond the factory floor. But with the average efficiency of large synchronous electric motors already being between 98.2% and 98.8%, can we push efficiency even further? The answer lies in understanding the fundamental sources of energy losses that occur inside electric motors. Physics imposes unavoidable limits, yet creative engineering continues to open up new paths for incremental improvement. At ultra-high efficiency levels, each small fraction matters. For instance, moving from the previous efficiency record of 99.05% to today’s 99.13% meant cutting energy losses by roughly 8%. Cutting losses by a further 8% – from 99.13% up to around 99.2% – would be exponentially more challenging. Much like trying to sweep up the last tiny crumbs at the end of cleaning the floor, each incremental gain now requires far greater effort. To push motor efficiencies, we rely on a constantly evolving R&D toolbox. We invest substantially to develop new technologies to enhance the performance of our products and services. Digital tools and modelling techniques have advanced significantly, enabling our engineers to explore more design possibilities than ever before. Instead of being tied to traditional configurations, design teams can now simulate and optimise fine details with great accuracy. Crucially, these efficiency gains are not coming from exotic or untested materials. Progress stems from a deep industry knowledge, increasingly precise manufacturing, and the creative application of proven technologies. Rather than relying on luck or breakthroughs, ABB’s recent record-setting efficiency achievement is a blend of expertise, careful optimisation, and practical decisions. This succeeds commercially because large industrial motors are typically custom-built, and are designed to match their intended use. Every motor project involves careful balancing between absolute efficiency and customer priorities, such as cost-effectiveness, reliability, ease of maintenance, and targeted applications. Still, the laws of physics dictate certain limits; no motor will ever achieve 100% efficiency. As motors approach these boundaries, diminishing returns set in. Every additional improvement demands much more R&D and manufacturing precision, yet yields smaller incremental gains. Standards and regulations help to define these efficiency levels. They're not obstacles or constraints; they're guarantees. When we say a motor is efficient, it has been tested, verified and proven. The transparency and accuracy of these standards matters to endusers who are becoming more energyconscious, as well as to supply chain partners who value certainty and reliability. Ultimately, customer priorities guide motor designs, and meeting these priorities depends heavily on industry standards. Bodies such as the International Electrotechnical Commission (IEC) set clear benchmarks for evaluating and declaring motor performance. Carefully structured testing protocols are therefore crucial, as they ensure efficiency claims remain credible, measurable and comparable across the industry. While the IEC 60034-30 series (MEPS IE1– 5) standards do not apply to large motors (above 1MW), some customers are already requesting the highest possible efficiency for their large electric motors. Others need more guidance or a gentle nudge. ABB’s Top Industrial Efficiency (TEI) initiative – which applies to the record-breaking motor – offers viable new efficiency options, making the journey easier. The higher efficiency options still fulfill the same requirements as the base offering, with no compromise on reliability or on using proven technology. Pushing the boundaries While hard physical limits remain fixed, the practical ceiling for motor efficiency will continue to rise gradually as digital tools, AI and precision manufacturing advance steadily. Each new milestone reflects our culture of continuous improvement and close collaboration between R&D and manufacturing teams. For us, every record is a step forward, not the finish line. Initiatives such as the TIE option ensure transparency in motor performance, showing customers the options available at each stage of their efficiency journey. This clarity helps industries keep moving forward, pushing achievable limits higher, one step at a time. Ultimately, improving motor efficiency is a careful balancing act – physics, economics, technology and customer priorities all come into play. ABB continues to lead industry R&D, consistently defining and redefining what's possible for industrial energy efficiency, making next-generation technologies both real and commercially viable. n ABB recently set a new world record for industrial motor efficiency of 99.13%. But what's behind this breakthrough, and how close are we to reaching the practical limits of electric motor efficiency? Gunnar Porsby, R&D lead for high-speed synchronous machines at ABB Motion High Power, examines the issues. ABB’s record-breaking synchronous motor was built for air separation duties at a steel plant in India
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