Magnetic Losses and microstructure in Electrical Steels
by Prof Fernando Jose Gomes Landgraf of Instituto de Persquisas Technologicas, Brazil

Assuming that Magnetic Loss Separation still offers opportunities for a better understanding of the role of processing and microstructure of electrical steels to losses in machines, new relevant quantitative information about such relations will be presented. The effect of chemical composition, grain size, second phases, dislocations and texture on hysteresis, classic parasitic and anomalous losses will be discussed, using the concepts of hysteresis loss subdivision and graphic representation of each loss component on the AC hysteresis curve to discuss possible energy dissipation mechanisms. Please Note: Prof Landgraf will not be attending the seminar, but speaking using Skype.

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Hidden Losses in Electric Machines
by Prof Tim Miller of

In electric machines, high efficiency implies low losses. Designers are therefore concerned to understand the separate components of power loss in order to minimize them, and in recent times it has become possible to calculate certain of these components more accurately using sophisticated numerical analysis. However, some of these “loss mechanisms” are not amenable to calculation at all. They may not even be definable in the precise terms of a posed mathematical problem, and this puts some of them beyond the range of even the most advanced numerical methods. The engineer is then thrown back on his or her proficiency in experiment, experience, and intuition — especially when tested efficiency falls short of the design prediction. The higher the efficiency, the smaller the individual loss components will be. In the pursuit of high efficiency it becomes necessary to consider “loss mechanisms” in more detail, and to pay attention to some that might be swept under the carpet as “stray losses” beyond the scope of the designer’s calculating ability — and even beyond his or her understanding. This discussion classifies the loss components into characteristic or principal losses, and parasitic or “non-characteristic” losses attributable to imperfections in manufacturing or design. A number of points are made concerning desirable practices at the design stage and at certain other stages including manufacturing, testing and operating the machine.

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Core Loss Characterization in Solids, Developing Specialized Test Setup for Unconventional Magnetic Circuits and Co-relating the Measured Losses to Estimate Losses in the Designed Machines
by Dr Gaurang Vakil of University of Nottingham

Characterization of magnetic material in the actual operating condition is absolutely essential. Laminated steels are having standard procedures that helps to test them and correlate the measured losses to the designed machines. But solid steel is a different contender. Measuring losses is difficult as it is difficult to maintain the temperature during the test. Again radial characterization is straight forward but characterizing for unconventional magnetic circuits is extremely tricky. This work gives the introduction of the characterization setup and presents the conventional way of characterizing solids (radial excitation). Solution to maintain the temperature for high frequency characterization of solids is presented. Next part deals with developing the test setup for characterizing steels for unconventional magnetic circuits. The final part of the work presents the way to correlate the test data to the designed machine.

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Rotor losses in PM Synchronous Machines
by Prof Suleiman Sharkh of University of Southampton

The talk will present recent work on the calculation of rotor losses in PM synchronous machines. Accurate calculation of these losses is critical as they tend to be very small compared to the other losses in the machine and a small error of a few tens of watts in the calculation of these losses may result in designing a machine that may fail or ruling out a feasible design. For example, in a commercial 60 kW, 60krpm generator a 25 W of loss is tolerable, but if the loss is say 50 – 100 W, then the rotor will overheat, which will lead to failure. Alternative methods and design variations that may be used to reduce rotor losses will be also discussed. The talk will conclude with a discussion of outstanding research questions that will be the subject of future research.

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Putting electric machine losses in context
by Dr John Reeve of FluxSys Ltd

This presentation will put electric machine losses into the context of the systems they form part of and the specific jobs they do. It will highlight the role of fully understanding system requirements, constraints and potential conflicts in specifying and designing ‘optimal’ electric machines. Taking high and low power automotive examples, this presentation will walk attendees through some of the many pitfalls the author has seen and provide some guidance to help avoid them including: - Deriving robust electric machine requirements - Focus on use cases and mission profiles, not operating points - Focus on loss maps and energy, not efficiency maps and instantaneous losses

Power Loss and Thermal Analysis in Modern Design of Electrical Machines
by Dr Rafal Wrobel of University of Bristol

The modern design of electrical machines is governed by numerous frequently conflicting design requirements, such as high-power/torque-density, high-efficiency, low-cost and high-reliability among others. These factors, together with the continuous drive to accelerate the development process, have imposed significant challenges for machine designers. In this context, a 'Design for Application' approach is necessitated, where all 'non-ideal' and 'essential’ multi-disciplinary effects are accounted for in a comprehensive manner. This presentation briefly introduces the ‘Design for Application’ methodology. Thereafter the focus moves to the multi-physics ‘Design for Performance’, a building block of the design paradigm. Here, a series of challenges associated with reliable predictions of the power loss and temperature in design of electrical machines are discussed. An experiment informed design methodology utilising various hardware sub-assemblies is presented next. This provides a mean to ‘fully’ inform the design process. Finally, a number of case studies are presented showcasing the proposed approach.

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