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2021 | Book

Energy Efficiency in Motor Systems

Proceedings of the 11th international Conference EEMODS’19


About this book

This book contains selected, peer-reviewed papers presented at the 11th International Conference on Energy Efficiency in Motor Systems (EEMODS'19), held in Tokyo, Japan from 17-19 September 2019. As with previous conferences in this series, EEMODS’19 provided a scientific forum to discuss and debate the latest developments and impacts of electrical motor systems on energy and the environment, energy efficiency policies and programmes adopted and planned, standards (including ISO 50.001), and the technical and commercial advances made in the dissemination and penetration of energy-efficient motor systems. Topics covered include: technologies, research and innovation in the areas of electric motors from life cycle costing to 3D printing to artificial intelligence/machine learning-based monitoring systems; emerging motor technologies; power electronics and drives; pump systems, including life cycle costing, energy efficiency improvements, maintenance, and operation for industrial, water supply and treatment, building, and irrigation; compressed air systems; fans /exhaust systems; refrigeration systems maintenance and operation; mechanical power transmission; motors in household appliances and HVAC (residential and commercial); motors and drives for transport applications including policies, programmes, regulation, and international standards; industrial management policies and standards; motor system audit and verification; policies, programmes and financing: analysis of motor system energy use and greenhouse gas emissions for motor systems, e-vehicles and related charging infrastructure; harmonization of global motor efficiency test standards; evaluation of utility programmes for improving energy efficiency in motor systems; and policy implementation, market surveillance and enforcement mechanisms, including case studies. The conference is international by nature and aims to attract high quality and innovative contributions from all corners of the globe, while the papers facilitate the development of new technologies, policies and strategies to increase energy efficiency.

Table of Contents

Novel Design of Delta-Connected PM Synchronous Machines Considering Rotor Skewing

In the design process of electrical machines – especially those with challenging performance requirements like traction motors – an individual adaption of the number of turns per phase plays an important role. Choosing a delta-connected winding instead of a Y-connection gives an additional degree of freedom in design. This can be of special importance in case of hairpin windings with their tightly restricted choice of the number of conductors per slot, as it allows to find a better match of flux, rated speed, and given voltage level. Although delta-connected windings are common in low voltage industrial applications, they are still underrepresented in traction applications. This chapter presents the most suitable design options for delta-connected PM synchronous machines and discusses their performance and efficiency in traction applications. Moreover, a new calculation method for a skewed rotor is presented. Instead of FEM calculations of several rotor slices, just one slice needs to be calculated by FEM. The flux density in all other slices is then derived from this result analytically.

Juergen Redlich, Anton Suchan, Bernd Ponick
EC-Motors in a Fan Application: A Case Study

Since a few years, Electronically Commutated motors (EC-motors) have gained interest in industry and more specifically in industrial fan applications. The EC-motor has become a serious competitor for induction motor speed controlled applications in the lower power ranges (up to several kW). Currently, EC-motors can be driven by standard voltage source frequency converters and come with better efficiency values compared to induction motors in the same power range. In this chapter, first the efficiency of such EC-motors is studied and lab measurements on commercial machines are performed to identify their potential with respect to energy savings. Efficiency/loss maps are presented and compared to those of speed-controlled induction machines. Next, based on this input, a case study on an industrial small fan application is performed. This techno-economic analysis shows the feasibility with respect to energy savings and also addresses the implementation effort and the barriers to convince the more traditional fan industry in order to consider the use of EC-motors in the near future.

Kurt Stockman, Jasper De Viaene, Steve Dereyne, Pieter Defreyne
A Global Update on the Markets for Motors, Drives, and Motor-Driven Equipment

This chapter highlights the findings of the latest analysis by IHS Markit on the global markets for low-voltage (LV) motors, variable frequency drives (VFDs), and motor-driven equipment, such as pumps, fans, and compressors. It will summarize how these markets are segmented by technology, geographic region, industry sector, and other emerging trends. In addition to presenting market data, the presentation will include an analysis of the current competitive environment for these products, including market shares of leading suppliers. A discussion on the impact of recent and impending energy-efficiency regulation initiatives will also be included in this presentation. Specifically, emerging and lesser-used technologies like permanent magnet motors, sensors, and other energy-saving methods will be assessed in order to show how commonplace these promising products are adopted. The main goal of this presentation will be to help the reader understand how much of a disconnect exists between government-led agendas and market-generated demand. Has the Industrial Internet of Things (IIoT) and similar initiatives such as Industry 4.0 become more pressing a topic for end users compared to a more efficient component or even a more efficient motor-driven system?

Preston Reine
Increasing the Energy Savings of Motor Applications: The Extended Product Approach

Motor applications account for about 45% of the global electricity consumption and represent one of the greatest opportunities for energy savings. The cost of the energy used by a motor represents about 95% of the Total Cost of Ownership leaving the purchase cost at only about 5%. Therefore, optimizing the energy consumed by motor applications is important to minimize both CO2 emissions and operational costs.However, using energy-efficient components does not guarantee the overall efficiency of the application (or Extended Product). The latter depends essentially on the architecture (which components are implemented) and on the operating point(s) of each component.The Extended Product Approach (EPA) developed in the IEC 61800-9 series of standards is a methodology for assessing the energy efficiency of an extended product (i.e., motor system and driven equipment) in the context of an application, considering the actual operating points.The main principle of the EPA is to provide means of determining the power losses of all components at any operating point. The resulting losses of the complete application can be calculated by weighting the losses at each operating point with its operating time. This approach is very generic and can be generalized to the other components of the motor application (transmission, mechanical load, process).This chapter provides a high-level view of the EPA to stakeholders who are not familiar with it. It also describes how the EPA could be applied to other parts of motor applications (power supply, mechanical components) to provide a consistent framework for assessing overall energy efficiency.

Benno Weis, Benoit Leprettre, Martial Patra, Norbert Hanigovszki, Preben Holm, Tim Schuman, Michael Könen, Niels Bidstrup, Kirk Anderson
High-Efficiency IE4 Line-Start Synchronous Reluctance Motors

The demand for energy saving and the new policies on the efficiency of motors for constant speed applications have shifted the interest of designers from conventional induction motors (IMs) towards alternative high-efficiency motors such as the line-start synchronous reluctance motor (LSSynRM). This type of motor is very cost-effective and can compete with the robustness and the low price of the IM. LSSynRM critical aspects are the rough starting transient, limitations in terms of pull-in (synchronization) capability and low power factor. In this chapter, a specific design procedure for LSSynRMs has been used in order to reach the desired balance between the pull-in capability, starting behaviour, and steady-state performance. It is the combination between finite-element (FE) analyses and optimization algorithms. The procedure is applied to design two LSSynRMs, 3 kW-2 pole and 4 kW-4 pole, 400 V, 50 Hz. The simulation results are compared with those of the IMs of the same size. A prototype of the 4 kW-4pole motor has been realized and tested. Then, its performance is presented in comparison with the IM counterpart. The LSSynRM proved to be a cost-effective, mass production-ready solution for super-premium efficiency IE4 motors, and it can effectively replace the conventional IM in a vast panorama of industrial applications.

Francesco Parasiliti, Marco Villani
Coordination of IEC and ISO Standards for Energy-Efficient Electric Motor-Driven Systems

Electric Motor-Driven Systems (EMDS) are currently responsible for some 53% of global electricity consumption (International Energy Agency, World energy outlook 2016, IEA, Paris, 2016). Optimizing the selection of the respective components (motor control, motor, mechanical equipment, and application) is a strategic prerequisite to realize the energy savings potential at system level; moving the optimization from component level to system level can realize extra energy savings with a factor 2 to 5 (van Werkhoven M, Werle R, Brunner CU (IEA 4E Electric Motor Systems Annex), Policy guidelines for motor driven units, part 1: analysis of standards and regulations, Zurich, Switzerland, 2016; Policy guidelines for motor driven units, part 2: recommendations for aligning standards and regulations for pumps, fans and compressors, Zurich, Switzerland, 2018). The design of the components, their sizing and selection, and their combination to form an optimal motor system together with a well-controlled operation need a system approach to optimize EMDS energy performance. Such system approach is not only needed at design level but also when it comes to standardization.

Conrad U. Brunner, Maarten van Werkhoven, Franco Bua, Kirk Anderson
Surface Eddy Current Suppression on Additively Manufactured Solid Rotor Active Parts

This paper describes the development process, 3D finite element analysis, and resulting design guidelines for reducing eddy current effects on solid rotor surfaces of electrical machines considering the three-dimensional freedom when designing parts that are suitable for additive manufacturing technologies. Today’s metal additive manufacturing technologies allow the processing of soft magnetic ferrosilicon alloys, which results in solid, non-laminated rotor active parts. With respect to permanent magnet rotors with buried magnets as in the present paper, it is necessary to groove the rotor surface in various manners to suppress eddy current effects. In a first step, a 3D finite element abstracted model, which optimally represents the rotor surface eddy current effects caused by higher spatial harmonics in a permanent magnet synchronous machine, is presented and numerically and analytically examined to find and describe an optimal rotor grooving method, in order to reduce eddy current losses and to derive specific design guidelines. In a second step, a test bench design is presented and numerically investigated in preparation for a validation of the theoretical results.

Max Hullmann, Stefan Urbanek, Bernd Ponick
Energy Scorecard: One of the Key Executions to Transform the Market for Energy-Efficient Motors

Turkey has an important place in Europe with the market size of 240 billion dollars in low-voltage electric motors. It is also estimated that there are approximately 15 million electric motors in the field. Most of these electric motors used in the field are inefficient motors. The motor regulation applied in Turkey is the same as regulation of European Union. Besides, a project named Promoting Energy-Efficient Motors in SMEs in Turkey that is TEVMOT has been initiated for the replacement of inefficient electric motors used in the field. Thanks to the TEVMOT project implemented by the Directorate-General for Industry and Productivity of the Republic of Turkey Ministry of Industry and Technology in cooperation with the United Nations Development Programme (UNDP) Country Office Turkey with the financial support of Global Environment Facility (GEF), it is desirable to create a sustainable model for the replacement of inefficient motors. In addition to giving full support to this project, Electric Motor Industrialists Association (EMOSAD) recommends the implementation of the energy scorecard model in order for the study to be successful.

Hakan Gedik
A Novel Approach to Predict Reed Critical Frequency of Vertical Motors

Natural frequencies of vertical machines or structures are termed as reed critical frequencies (RCF). They can be termed as the first natural frequency of the vertical machines in transverse direction. Their calculation becomes critical as they can harmonically interact with the driven component leading to resonance condition causing catastrophic failure during operation. This resonance condition can be eliminated by maintaining adequate separation of margin between RCF and operating speed or excitation frequency. As most of the application demands a constant operating speed, the feasible way to avoid resonance is to move the RCF away from the operating speed.Presently, few methods of predicting RCF are available. The first such method is to simulate the full motor assembly using finite element analysis with suitable boundary conditions. This method is extensive and sensitive to various factors. The second method as proposed by National Electrical Manufacturers Association (NEMA) treats the motor as a single degree of freedom system and predicts the frequency with static deflection of motor at Centre of Gravity. This method is very rudimentary, and the third method is to perform bump test on machine, which is time consuming and costly for every motor. In industrial applications, motor manufacturer must submit a motor outline drawing with RCF within ±10% accuracy well before the final stage of design. However, neither of these methods gives accurate and cost-effective solutions.This work proposes a methodology for predicting RCF of vertical motors on solid foundation considering it as a two degrees of freedom system, by proposing a mathematical model to predict the natural Frequencies of vertical motor by converting the motor geometry into the equivalent simple structures using Timoshenko beam model. The aim of this work is to reduce resources utilized to predict RCF with an accuracy of ±10%. Frequency of different enclosure motors (WP-I, WP-II, TEFC) is simulated using finite element method and the motor simplification is done as a beam with elastic mass attached over it. The study also includes the behavior of the dynamic system with mass and stiffness contribution for different components in the assembly. Finally, the validation with bump test data proves the concept across different frame sizes and enclosures.

Ravi Musinana, Harendra Singh
Evaluation of High-Tech Electrical Steel in a High-Speed Permanent Magnet Synchronous Machine for an Aircraft Application

A major design challenge of high-speed high-power machines is the dissipation of heat resulting from the occurring losses. Higher rotational speeds require a high base frequency of 1 kHz. Thus, such a design will have high hysteresis losses and eddy current losses in its iron paths. Thinner electrical sheets and iron alloys with lower specific loss, e.g., cobalt-iron, are used as one countermeasure. However, given the challenge of an aircraft application with the demands for low weight and a small build volume, further aspects such as the difference in density and the heat transfer characteristics have to be considered as well. This paper compares an already existing machine design built with silicon-iron electrical sheets to further iterated designs based on a very thin cobalt-iron material at the same operational conditions. Furthermore, a new machine with higher pole pair number is designed to take advantage of the low loss coefficients and, consequently, make use of a higher operational frequency. The pros and cons of these machines are evaluated using finite element and numerical simulations for electromagnetic and thermal aspects. The results show the advantage of high-tech thin cobalt-iron alloy electrical steels in the field of electrical machines with a high power-to-weight ratio of 10.31 kW/kg for the active part of the machine compared to 7.35 kW/kg using a silicon-iron material.

Mina Mirzadeh, Gerrit Narjes, Bernd Ponick
New Life Calculation Model for Hybrid Bearings

Hybrid bearings are bearings with rings made of steel and rolling elements made of ceramic silicon nitride (Si3N4). They are used in demanding application conditions, like compressor (Morales-Espejel, GE, Hauleitner R, Wallin HH, Pure refrigerant lubrication technology in oil free centrifugal compressors. SKF Evolution #1, 2017, pp 26–30), pumps and e-motors. Hybrid bearings are also used for their insulating properties. As a non-conductive material, silicon nitride protects the bearing rings from conducting electric current, thereby preventing damage caused by electrical erosion. This can occur if there is a voltage difference between the rotor and the housing.Recently SKF introduced the Generalized Bearing Life Model (GBLM), and since then, work has continued focusing on specialized bearings and experimental validation of the model. In order to take the full advantage of all key factors in the bearing selection. SKF has developed life calculation for hybrid bearings. Due to the higher stiffness of the ceramic, the Hertzian contact area is slightly smaller in a hybrid bearing leading to higher contact pressure and subsurface stress compared to a bearing of equivalent geometry made entirely in steel. In principle this should cause a reduction of the fatigue lifetime of the bearing. However, it has been observed that in typical applications hybrid bearings last longer. How to explain this odd behaviour? How to model it? In this paper these questions are addressed; it is also shown that GBLM can model and explain well the observations in the field.

Author Magnus Arvidsson
Programme for In-Depth Analyses of Electric Motor Systems in Industry (ProAnalySys)

All Swiss companies are classified into four main categories based on their energy consumption: small, medium, large and very large companies. The first two categories represent less than 3% of the total number of companies, but account for almost two-thirds of Switzerland’s total electricity consumption. For this reason, both the federal government and the cantons stipulated that these companies must reduce their energy consumption. Consequently, they are required to perform an energy audit in order to evaluate their energy-saving potential and thus define a set of efficiency measures that they undertake to implement over a 3-year or up to a 10-year period. However, these audits are quite superficial and do not indicate whether the output of the operated motor systems corresponds to the effective needs. Replacing an existing motor with a premium or even a super-premium model is a simple measure, but it does not give rise to significant electricity savings. Such mandatory energy audits are not sufficient: what is needed is an in-depth analysis during which certain measurements may also be necessary. These in-depth analyses are expensive and time-consuming and call for special expertise as well as appropriate equipment and software. In view of this, the Swiss Federal Office of Energy (SFOE) decided to launch a subsidised programme aimed at promoting in-depth analyses among energy-intensive companies and large-scale consumers, as well as supporting them with the implementation of their resulting voluntary efficiency measures. This paper presents the framework conditions and objectives of the programme (called ProAnalySys), plus some examples of in-depth analyses performed on swimming pools, cable railways and refrigeration installations.

Richard Phillips
A Review of the United States Process for Developing MEPS, the Benefits, and How Other Economic Regions Could Benefit from Adopting Similar Approaches

The United States has been at the forefront of developing energy regulations for over four decades. During this time, a Process Rule has been used to create dozens of regulations. This chapter examines how the Process Rule works today, including the various stakeholders typically involved in developing MEPS, rules for developing regulations, and efforts underway to improve the existing process. The chapter also includes two examples of regulations and the outcome of each. Finally, the chapter lists benefits by incorporating the Process Rule as a model.

Kirk Anderson, Rob Boteler
Electromagnetic Design of Propulsion Motors with Superconducting Field Coils for Electrified Aircraft

This paper describes the output power density of partially superconducting motors (PSCMs), which have superconducting field coils and copper armature windings, for electrified aircraft propulsion systems (EAPSs). In EAPSs the aircraft’s fans are driven by electric motors. For electrified aircraft with a capability of more than 100 passengers, the electric motors are required to have high output power density of 16 kW/kg or more, whereas the power density of a conventional synchronous motor is limited to around 5 kW/kg. PSCMs have a potential to achieve such a high output power density because of high current density of the superconducting field coils and high magnetic flux density generated by them. The output power densities of 5.5 MW PSCMs were estimated at different operating temperatures of the field coils by analytical equations and FEM analysis. The design results showed that the output power density reached 16.1 kW/kg at 20 K and 12.0 kW/kg at 65 K. From these results we consider that the PSCMs at 20 K have a potential to be adopted in EAPSs in terms of high output power densities. The output power density of PSCMs at 65 K is more than double compared to conventional electric motors, although the required output power density could not be attained.

Yusuke Ishida, Yutaka Terao, Hiroyuki Ohsaki
Design Methodology for a PM Electrical Variable Transmission Used in HEV

Designing a permanent magnet electrical variable transmission is a cumbersome task, regardless of the considered application. The main reason for this is the iterative design process using a computationally intensive finite element model calculations that is necessary to model its behaviour. This makes it difficult to study or visualize the impact of design changes on, for example, the fuel consumption or cost of a hybrid electrical vehicle. To solve this, electromagnetic scaling laws are used to set up a performance map of the entire system. This map is able to present the performance (i.e. fuel consumption, cost, maximum acceleration, etc.) as a function of an axial and radial scaling factor. The map thus displays the performance of a series of designs which enable the reader to select the optimal one in a graphical way. Furthermore, feasibility constraints such as maximum weight, are added. These constraints allow to reject designs but make it also possible to study the performance as a function of weight or material cost. This is particularly useful for manufacturers as it gives an idea of how their investment is translated into a reduction in fuel consumption.

Florian Verbelen, Hendrik Vansompel, Ahmed Abdallh, Kurt Stockman, Peter Sergeant
IE3 Efficiency Class as MEPS for Industrial Motor: How Brazil Got There

The industrial motor market is huge in Brazil; around 2.7 millions units were commercialized, and the nationally installed motors in industrial plants were estimated in more than 20 million units in 2016. Their electric energy use, only for the industrial sector, is approximately 25% of the total national energy consumption. Due to the relevance of these machines, the government started effective actions to improve their technology and usage in 1992 (Soares G, Pinheiro M, Shindo R et al, The target program for three-phase induction motors. In: Proceedings of energy efficiency in motor drive EEMODS – 05, Heidelberg, Germany, September 2005).The first MEPS for industrial motors occurred for IR1 efficiency class, similar to IE1 in 2002. The MEPS were raised to IR22 level in 2010. Two years later, the Brazilian Technical Committee started developing some studies to establish the next step for MEPS, as presented in EEMODS’13 (Soares G, Ferreira CA, Costa EA, Santos MA, Leme AP, IS IE3 efficiency class: a feasible next step for industrial motor’s MEPS in Brazil? In: Proceedings of 8th energy efficiency in motor drive EEMODS – 13, Rio de Janeiro, Brazil, October 2013). However, the market conditions, the global competition of Brazilian OEMs, and the increase of imported motors made the market need more time to absorb the IE2 as MEPS. In 2016 and 2017, some accurate studies were carried out to understand the market barriers and to re-estimate the gains for the society, including the power sector and consumer views. The articulation of representatives from the business sector, public sector, and civil society organizations was carried out to ensure a feasible regulation.In August of 2017, a governmental directive was enacted establishing IR32 (IE3) efficiency class for the new MEPS for industrial motors. This measure took effect 2 years after the date of its publication in the Official Journal. Two years were considered the time needed for market preparation. Additionally, in an innovative way, this regulation includes also commercialized repaired motors, another big issue in Brazil.This paper presents the national motor market, the gains and the barriers of the IE3 efficiency class as MEPS in Brazil, and all activities that took place for achieving this enacted regulation.

George Alves Soares, Carlos Aparecido Ferreira
A Decision-Making Tool Incorporating Multiple Benefits of Motor Systems’ Retrofits

Investments into energy efficiency in companies are currently considered rather one-sided, for the most part focusing on financial aspects only. Further benefits such as operational security, employee productivity, etc. are not systematically included in the investment analysis.According to the final report of the research project Management as a Key Driver of Energy Performance from 2018, ‘Energy efficiency provides numerous benefits to companies, including improvements in worker comfort, product quality, overall flexibility and productivity, as well as reductions in maintenance cost, risk, production time and waste’. The overall benefits of energy efficiency improvements are not only related to energy but also include non-energy aspects and are often referred to as multiple benefits. Non-energy benefits can have more importance than energy benefits only and ultimately help in convincing company management to invest into energy efficiency – having a positive overall impact on companies’ competitiveness. Thus, multiple benefits, which include both energy and non-energy aspects, have a significant potential in triggering the (timely) replacement of existing installations (Management as a key driver of energy performance – final report, 15 November 2017; ).A Swiss project aims to develop a decision-making tool for motor systems that supports decision-makers in small and large companies, incorporating the aspects of multiple benefits. Since electric motor systems are widely used in companies of all sizes across different sectors (primarily in the industrial and services sectors), the market potential of such a decision-making tool is considerable. In addition to a technical approach, socio-economic as well as investment-related aspects will be incorporated, so that the basis for decision-making has the necessary breadth. The final product shall be a web-based tool, which is easily available and applicable for the target group.The project is implemented in three phases and concluded by mid-2020: 1. Phase 0: In this preparatory phase, the general approach was established, taking into account technical, behavioural and financial aspects. Interviews were conducted with four organisations, laying down the groundwork. 2. Phase I: Following the preparatory phase, relevant multiple benefits will be further elaborated, identified and validated, based on interviews and data analysis. Four applications of motor systems will be analysed, namely, air compressors, cooling compressors, fans and pumps (and in addition as an option variable frequency drives). 3. Phase II: The results of Phase I will be integrated into a web-based decision-making tool. 4. Phase III: Dissemination of the tool to relevant stakeholders. This paper focuses on the methodological approach taken and the results so far (Phase 0).

Rita Werle, Rolf Tieben, Petar Klingel, Andreas Rothen, Lea Fleischli, Victoria Pyatova, Shaun West, Kurt Ackermann, Richard Phillips
European Ecodesign Material Efficiency Standardization Overview for Circular Economy Aspects in Motor and Power Drive Systems

The European Commission launched end of 2015 a circular economy strategy with an action plan for “Closing the loop.” One action from this initiative was to request the European standardization organizations to prepare a series of horizontal standards for setting ecodesign requirements for circular economy by considering the durability, the reparability and the recyclability of energy-related products like electric motor, variable speed drives, pumps, or fans. This paper will report on the standardization work in progress in the CEN-CLC Joint Technical Committee 10 in charge of these standards, dealing with topics such as the durability; the ability to repair, reuse, upgrade, and remanufacture products, the recyclability and recoverability; as well as the assessment of ratio for reused components or recycled material in energy-related products, and the declaration of European critical raw material and information related to these material efficiency aspects.Attention will be considered for material efficiency requirements from the European Ecodesign Regulation published in 2019 for motor and variable speed drives. There is a need to carefully consider the possible technical conflict raised when compliance to resource and material efficiency along the complete product life cycle is to be satisfied at the same time with energy efficiency performance in the product in use phase.Consideration for specific product-oriented material efficiency standards will be discussed based on the generic horizontal European EN 4555x draft standard series which do not differentiate between requirements applicable for household equipment for business-to-customer market (B2C) and non-household/industrial equipment and systems for business -o-business market (B2B). Also, there is a need to consider a guideline on the direction and advice on how to derive and manage different horizontal requirements and on how to apply them to particular energy-related products like motors, power electronic drives, pumps, compressors, or fans. In particular, for standardization product committees are expected to draft a unique product-oriented standard covering all aspects of material efficiency for circular economy, as described in the whole EN 4555x series of CEN CENELEC documents to be published soon.

Martial Patra
Comparison Between the Use of the Middle Ring and/or Skewed Bars in Induction Motor Rotor

The chapter compares several results of laboratory tests of induction motor rotors with different squirrel-cage characteristics, like skewed bars and the use of a middle ring. It is intended to make comparisons between rotors that do not use any of these characteristics and rotors that use only one or both of them. The comparisons are based on laboratory tests, namely: performance test in steady state, torque-speed curve, and noise test at rated load. The results show that either skewed bars or middle ring has a relevant impact on the overall performance of the motor. Therefore, depending on the application of the motor, the adoption of one or both the characteristics can help the motor to meet the performance requirements.

Marcelo Dias da Silva, Daniel Schmitz, Carlos Manuel de Araújo Sá, Bruno Baptista, Sebastião Lauro Nau
Efficiency Measurement Strategy for a Planetary Gearbox with 2 Degrees of Freedom

This chapter discusses a method to calculate the efficiency of a planetary gearbox with 2 degrees of freedom. Standard measurement procedures in which the efficiency is measured as function of the load torque and input speed become infeasible due to the many possible input output configurations. To solve this, a method is proposed that combines the theory of virtual power and a limited set of measurements. The theory of virtual power is used to link the considered power flow in the device with an expression to calculate the efficiency of the planetary gear in terms of the efficiency of the power path between sun and carrier and carrier and ring. The efficiency of the aforementioned power paths is shown to depend only on the torque applied to these paths which means that speed-dependent losses such as churning losses are negligible. Measurements of the efficiency as function of the torque applied to the sun for a varying speed ratio between ring and carrier are added to validate the approach.

Florian Verbelen, Pieter Defreyne, Peter Sergeant, Kurt Stockman
Development of High-Precision Efficiency Measuring Device for High Power Motor Drive Systems

In recent years, in the field of power electronics, especially for automobiles, railways, aircraft, etc., the miniaturization and high efficiency of inverters that are the main components of motor drive systems have become important issues. The switching frequency of inverters equipped with wide bandgap power semiconductors typified by SiC and GaN has been increasing steadily, and higher precision power measurement is required for the efficiency measurement of input/out power and conversion across a broader band more than ever before. In particular, although the output power of inverters driving motors includes a switching frequency and its harmonic components, there has been no measuring instrument that can measure these signals accurately until now.The newly developed current sensor is a manifestation of advanced technology involving winding and magnetic core that achieve a broad band, improved noise resistance performance and common mode rejection ratio (CMRR) via a shield structure, and a magnetic balancing circuit technology that realizes high precision linearity. Through this fusion of technologies, we achieved a very wide measurement bandwidth of DC to 1 MHz (−3 dB) for measuring a large rated current of 2000 A. We also developed a highly accurate measurement system to measure the efficiency of motor drive systems with high precision by incorporating a current sensor phase shift function via a wideband current sensor and power analyzer. As an actual measurement example, we will introduce the measurement results of the motor drive system, and show the effectiveness of the newly developed measurement equipment.

Masayuki Harano, Hiroki Kobayashi, Chiaki Yamaura, Kenta Ikeda, Koki Nakazawa, Shozo Yoda
Evaluation and Application of Existing Air Curtain Effectiveness Methodology

Air curtains have been widely used on building entrances as a barrier to reduce energy losses due to infiltration/exfiltration while still permitting unobstructed passage of pedestrian traffic. Many building energy codes are published that prescribe the requisite for energy-efficient designs. These codes address building entrances that separate conditioned space from the exterior with a requirement that they shall be protected with an enclosed vestibule. Recent studies examine and validate the performance or effectiveness of air curtains at a macro or whole-building perspective and compare that to vestibules. The studies illustrate that several factors impact air curtain effectiveness including air discharge velocity, angle, door height and width, and indoor and outdoor pressure conditions. Existing test methods (and associated standards/codes) evaluate the effectiveness based on either (1) the aerodynamic characterization of air curtain through the measurements of air curtain jet velocity distribution and degradation, or (2) the measurements of infiltration/exfiltration rates with/without the air curtain under different operating conditions, that is, pressure difference across the door. The first method is easier to be conducted but is not directly related to evaluating the capability of reducing infiltration/exfiltration whereas the second method can do so by testing each specific unit, which is often costly, time-consuming, and sometimes impractical. Therefore, a relatively simpler method is required to combine both methods for the evaluation of air curtain effectiveness during its design, selection, and operation. This study aims to develop such a calculation method to relate the aerodynamic performance test method in American National Standards Institute/Air Movement and Control Association (ANSI/AMCA) Standard 220-05 or International Organization for Standardization (ISO) 27327-1:2009 directly to evaluating the air curtain’s capability of reducing infiltration/exfiltration rates. It is proposed that an air curtain discharge be separated into several subsections to consider the diversity of the discharge velocity along the air curtain width. Case studies are provided for the demonstration of the whole process. A validation study using the previous experimental results is also conducted. In comparison to the existing effectiveness test methods, the new method is a more feasible solution to various air curtain products and installation scenarios.

Liangzhu (Leon) Wang, David A. Johnson, Frank Cuaderno
Promoting CO2 Water Source Heat Pumps in Indian Industrial Sector

The electric CO2 water source heat pumps (EHP) generate hot water and cold water simultaneously using the trans-critical cycle of the natural refrigerant CO2. Since their introduction in 2001, EHP were regarded as the next generation of low-carbon technologies. The results from piloting EHP at two dairy plants, one in Anand, Gujarat, and other in Chandigarh, Punjab, in India, by the Institute for Global Environmental Strategies (IGES) and The Energy and Resources Institute (TERI), revealed that a potential of 30–50% primary energy saving is possible depending upon the unit-level existing scenario; and consequently, a potential CO2 emission reduction up to 180 tons/year.On impact analysis of installing EHP of similar capacity at 50 dairy plants in both the states of Gujarat and Punjab, the authors found that the replication could result in equivalent primary energy saving of 952 toe/year, and a reduction in CO2 emissions of 3128 tons/year.EHP are ideal not only for dairy industries but also for applications that require both hot water and cold water regularly; therefore, significant potential exists for implementing them in the Indian industrial sector. To tap such potential, the authors call for addressing three types of barriers that were observed: (1) high initial investment cost, (2) lack of awareness about EHP, and (3) limited technical capacity on how to operate and maintain EHP.To overcome the financial barriers, the authors recommend the use of existing financial schemes, including the financing under the credit scheme initiated by Japan International Cooperation Agency (JICA) and Small Industries Development Bank in India (SIDBI). To overcome the lack of awareness and to develop the technical capacities regarding EHP, the authors recommend the use of the Japan–India Technology Matchmaking Platform, which was initiated to promote Japanese low-carbon technologies in India.

Abdessalem Rabhi, Ananda Mohan Ghosh
Refrigeration Systems: Optimal Temperature Setpoint Regarding Air Mixing in a HVAC-R System

In some heating, ventilating, air-conditioning, and refrigerant (HVAC-R) systems, a limitation on the temperature differential between the interior temperature setpoint and the outdoor temperature can exist to limit energy consumption. For example, when a temperature differential limit = 5 °C and the outdoor temperature = 30 °C, the effective temperature setpoint cannot be below 25 °C even if the user requires a temperature setpoint at 20 °C. This option is effective in terms of energy savings but will affect the user comfort. Air mixing technology with registers (dampers) allows for energy savings by mixing air from interior with air from outdoor (new air). This mixed air will be sent to the evaporator in the air-conditioning (AC) configuration, or to the condenser in heat pump (HP) configuration. In the case of 100% recirculated air and stabilized system, the air temperature at the evaporator outlet will not be directly impacted by outdoor temperature/humidity, contrary to the case of non-air-mixing.This chapter, with the help of physical equations, deals with relationship between exterior parameters (temperature, humidity, heat input) and required energy to maintain a room at a given temperature with a given air mixing. Thanks to this relationship, a strategy about maximum temperature differential can be elaborated to limit energy consumption and guarantee the best user comfort.

Jérôme Jeanclos, Kamal Ejjabraoui, François Malrait
Modeling of Radial and Tangential Roebel Bar Force Distributions in Large Electrical Machines Considering Longitudinal Transposition

The radial and tangential force components acting on each sub-conductor of a Roebel bar in a large generator lead to mechanical vibration of conductors. This double-frequency vibration results in insulation deterioration and looseness of stator bars. Understanding the origin of these vibrations and developing models to anticipate them is essential to increase the reliability and expected lifetime of these systems. This chapter presents a comprehensive study on the origin and behaviors of Roebel bar vibrations under different operation modes. A 3D-FEM model of a generator is developed and the vector potential values in the air gap are calculated. These vector potential values are applied as boundary condition to a detailed 2D-FEM model to calculate the sub-conductor forces. The results obtained from Maxwell stress tensor and Lorentz force methods are compared to each other. Moreover, the Roebel bar force behavior for different power factors and load angles is investigated.

Amir Ebrahimi, Marius Meiswinkel
NH3-CO2 Brine System for Refrigeration at Cold Storages and Seafood Processing Plants in India

The Government of India has set targets to reduce 85% of the use of hydrofluorocarbons (HFCs) by 2047 (over the 2024–2026 average levels). Based on onsite visits to randomly selected seafood processing plants and cold storages in Andhra Pradesh, India, the authors found that more than 70% of them use reciprocating compressors based on HFC (R404a) refrigerant and are not aware that HFC has to be phased out.This chapter is addressed to seafood processing plants and cold storage owners in India who are currently using HFC-based refrigeration systems. It proposes to consider shifting to use the NH3-CO2 brine system by highlighting its safety, energy efficiency, and cost-saving aspects based on a feasibility study conducted at cold storage located in Andhra Pradesh, India.The feasibility study revealed that the proposed NH3-CO2 brine system could give better performance than R404a-based refrigeration system at all loads. For instance, at maximum loading of 201.6 kW, the energy savings at 60%, 80%, and 100% loads are 24.6%, 30.24%, and 29.08%, respectively. Consequently, the CO2 emission reduction ranges from 119 ~ 241 tCO2/year and the cost-saving ranges from 9 Million ~18 Million Rs/year, which makes the payback period within 4 years, assuming the localization of its critical components in India.Besides, the chapter introduces a comprehensive framework of partnership that could be considered to adopt the proposed NH3-CO2 secondary system widely in India.

Abdessalem Rabhi, Rudhi Sundar Pradhan
Semi-analytical Calculation of Field and Loss Distribution in the Tooth Tips of Electrical Machines

This chapter investigates a novel approach to calculate the iron loss distribution in the stator tooth tips of electrical machines. First, an analytical field calculation approach is presented beginning with a Schwarz-Christoffel mapping of the tooth tip to a rectangular shape. Solving the Laplace equation for this geometry and deriving the correct boundary conditions allow the calculation of the normal component of the flux density on the tooth surface. The field distribution inside the tooth is calculated with a magnetic admittance network solved using nodal analysis. Besides presenting the calculation of the spatial and time-dependent field distribution in the tooth tip, an iron loss model is introduced. The overall agreement of the model with measurements is very good over a large frequency and flux density range. To validate the field calculation results, both the semi-analytical field calculation results and 2D FEA results are used as input for the introduced loss model. Comparisons indicate a very good match between the presented approach and FEA.

Alexander Rehfeldt, Torben Fricke, Babette Schwarz, Amir Ebrahimi, Bernd Ponick
The Effect of Top Runner Motor (IE3) Regulation in Japan

The Top Runner motor regulation started on April 1, 2015, in Japan. The law is named as “Energy Management based on the Act on the Rational Use of Energy” (hereinafter referred as “ECL”: Energy Conservation Law) and requires an annual report from the motor manufacturers and importers (hereinafter refers as “motor makers”) of their domestic shipments quantities (production and import quantities) and efficiencies in the target fiscal year 2015. All motor makers in Japan have to report annually according to the requirements of the ECL. This chapter shows the analysis of the report submitted by JEMA’s members (motor makers). It covers the production of approximately 70% of the Japanese motor market. 1. Transition of the ratio of the number of IE3 motors to that of all motors. The report contains data of 36 categories by output power and frequency. ECL requests to satisfy the regulated efficiency in each category. All motor makers in Japan satisfied this regulated efficiency in all categories. The result is as follows. Annual year Top runner motor (IE3)/total production (units) Efficiency accomplish rate 2016 64.0% 101.9% 2017 66.6% 101.6% The distribution of low-voltage motor efficiency classes in the world is IE4 < 1%, IE3: 18%, IE2: 34% in 2016, according to the contents reported by IHS at “Motor Summit 2018”. The segment over IE3 class is less than 19%. It can be said that the 64% of the motor market share by the IE3 class in Japan is a good value in 2016 – compared to the global data. 2. Next stage. This result shows there is still a share of 33% of the motors in Japan which do not comply to the regulation. The purpose of ECL is to save energy and to reduce greenhouse gas. The target is to bring built-in motors and motors installed in other facilities into the Top Runner motor regulation.

Takeshi Obata
The Market of Electric Motors, Pumps and Fans in the European Union and in Switzerland

The Swiss Federal Office of Energy (SFOE) is the public regulator establishing Minimum Energy Performance Standards and conducting market surveillance in Switzerland. In order to better understand and steer the market transformation, SFOE has started an annual monitoring of the motor market in 2017. A first report was published in 2018 giving an overview of the efficiency, number and size of motors sold in Switzerland in 2016. In 2019, the second report was published, giving an overview on motors, pumps, and fans not only on the market in Switzerland but also the European Union (EU).The results show: From the total 180,000 electric motors sold in Switzerland in 2017, approximately 70,000 were subject to the Swiss Minimum Energy Performance Standards (MEPS). From the motors in scope of the MEPS, 64% were of the IE4 and IE3 energy efficiency classes (IE code, based on IEC 60034-30-1, 2007), 35% of the IE2 class and less than 1% of the IE1 class. The price of an IE3 electric motor compared to IE2 was 14% higher. An IE4 motor costs 17% more than an IE3 motor. From the total 400,000 circulator pumps (integrated and nonintegrated) sold in Switzerland in 2017, 98% had an energy efficiency index (EEI) below or equal to 0.23, thus compliant with the respective MEPS. In the European Union, 91% of the total 17.9 million circulators sold had an EEI below or equal to 0.23. From the total 50,000 water pumps sold in Switzerland in 2017, 91% were below 10 kW. 40% of all water pumps sold in Switzerland were multistage submersible pumps. The respective figures for the European Union are: from the total 2.7 million water pumps, 85% were below 10 kW. The share of multistage submersible pumps in the EU was 45%. From the total 115,000 fans sold in Switzerland in 2017, 22% were forward-curved and radial bladed fans and only 19% (the more efficient) backward-curved fans. From the total 11.6 million fans sold in the EU, 24% were forward-curved and radial-bladed fans and 18% backward-curved fans. This market analysis was done in the framework of the Swiss Topmotors program ( ) by the independent consulting company Impact Energy, as mandated by the SFOE, in collaboration with the global market research company IHS Markit (today Omdia). The analysis is based on direct surveys of relevant manufacturers. This chapter focuses on the main findings of the 2018 survey and analysis.

Rita Werle, Conrad U. Brunner, Rolf Tieben, Petar Klingel, Richard Phillips
Pilot Audit Program for Electric Motor-Driven Systems

Efficient electric motor-driven systems (EMDS) can make an important contribution to achieving (inter)national energy savings and CO2 emission reduction targets. Recent energy and climate research in the Netherlands show that energy savings and reduction targets are lagging behind the set targets for 2020 and beyond. A pilot audit program for EMDS has been started to scale up and harvest the considerable savings potential in motor-driven systems that are present in industry.The audit program is aiming to conduct 150 audits and to develop a number of practical business cases for industrial companies. The audits will lead to the identification of energy savings potential and CO2 emission reduction potential at the participating industrial companies, will specify a number of business cases ready for direct implementation, and will be a starting point for continued savings in the coming years. A voucher program will be put up as incentive for industrial companies. The designated audit methodology follows the ISO50002 standard, adjusted for motor-driven systems, as defined by the Energy Audit Guide for Motor-Driven Systems. The methodology and the initiative itself will be tested in 30 pilot audits,and then, by adequate results, followed by 120 audits through a voucher scheme. Specific tools are available for the auditor; for each of the three audit phases, a specific tool is available: i.e., tools for the first overall assessment of the savings potential and tools for the selection of potential optimization measures – identifying a top 20 and five “business cases” – among which the Motor Systems Tool. All tools are manufacturer-independent tools. All audits have to comply to a specific audit format and report.In parallel a training has been developed for employees from industry, service companies, and manufacturers. This training covers a technical curriculum on the different fields of a motor-driven system, like mechanics, electrotechnics, energy systems, and automation. A second part has special focus on personal social skills including awareness and training of presentation skills. The program covers a practical assignment in an industrial facility, as well as classical education and e-learning modules.The two “tracks” combine synergies toward the needed capacity building in industry and service sector and the concrete identification and implementation of energy efficiency measures. At EEMODS the first results and an assessment will be made available.

Maarten van Werkhoven, Frank Hartkamp
Operation Analysis of an Integrated Linear Flux Modulating Motor for a Direct-Driven Belt Conveyor

The following article covers the novel design of a linear flux modulating motor for direct-driven belt conveyors and gives an insight into considerations for manufacturing and system efficiency. In common approaches, belt conveyors are driven by attaching a geared electric machine to one of the drums, using the traction force between the drum and the belt to introduce linear motion. Since the contact area between the belt and the drum is small compared to the total belt surface, the achievable force in contact with the drum is limited. In order to increase the traction force between drum and belt, the tension inside the belt must be increased. The downside of this is higher mechanical stress and more complex belt designs to withstand the additional force. To overcome the mentioned aspects of common belt conveyors and to pave the way for new material flow models, a novel highly integrated direct-driven belt conveyor is presented. Efficient 3D FEM simulation results are provided, utilizing the symmetric properties of the motor to reduce simulation time considerably. In addition, an optimized design is presented resulting in a decreased force ripple and higher average force. Furthermore, an efficiency map for the desired operation range is given.

Alexander Hoffmann, Malte Kanus, Ludger Overmeyer, Bernd Ponick
Performance of Copper Rotor Motor in High-Speed Applications

This chapter introduces the development and performance analysis of copper rotor in high-speed induction motors, which included the application of high-speed spindle motor and electric vehicle traction motor.The experimental data and performance analysis were given, which shows that the use of copper rotor technology can increase the motor torque, reduce the rotation variables, and ensure the dynamic response speed and accuracy of the motor. At the same time, it can significantly reduce the temperature rise and increase the power density of the motor. By using copper rotor, it can significantly reduce the noise and vibration and improve the efficiency level of the motor.

Dong Liang, Sheng Zhou, Datong Yang, Xu Yang
Development and Loss Evaluation of High-Speed PM Synchronous Machine

This paper presents a performance evaluation for a 250 kW–20,000 min−1 high-speed permanent magnet (PM) motor for high-speed applications such as industrial blowers and compressors. Active magnetic bearings used in the high-speed motor floats shaft without contact and realizes direct drive system. The utilization of a high-speed motor for a direct drive system can contribute to making the system size more compact when compared to a geared system. However, this could cause the motor loss density to be high due to the high-output power density in the high-speed motor. For realizing higher-output and higher-speed motor, to clarify loss-generating source in the motor is a very important issue. At this time, we evaluated the electrical characteristics and efficiency of the prototype 250 kW–20,000 min−1 high-speed PM motor and measured the temperature increase by carrying out a heat run test. Furthermore, loss separation was performed. In addition, another fundamental evaluation of windage loss and iron loss that were dominant in the motor loss clarified by above results was performed to improve the efficiency and design accuracy.

Mototsugu Omura, Sho Uchiyama, Keisuke Matsuo, Takashi Okitsu, Takayuki Mizuno, Koji Yamada, Kouki Matsuse
Regulation and Enforcement [Surveillance] Consequences

Sovereign states around the world have created electrical product efficiency performance [MEPS] for more than 20 years. Test methods and lab requirements have evolved over this period to remarkable tolerances and repeatability standards. Yet, imports of covered products imported as stand-alone units or a component of a larger piece of equipment have little to no required documentation compliance validation at the point of importation. Most country boarders remain open to an unrestricted flow of these products entering the local market competing with in-country compliant product suppliers.This paper will evaluate the impact to consumers, suppliers of compliant product, and the energy savings not realized by the regulating country as a result. The paper will discuss examples of ways the USA has begun to evaluate documentation of regulated products and methods used to better control the influx of products to assure compliance to national efficiency regulations.The paper will lay out the way the US Department of Energy has proposed implementing compliance, certification, and enforcement measures to enforce motor regulations and deliver projected energy savings.

Rob Boteler, Kirk Anderson
Strategies to Promote Energy-Efficient Compressed Air Systems Among Indian Companies

Compressed air systems account for 5–35% of electricity use among the Indian manufacturing sector. It shares a significant portion of the production cost, but its energy-efficiency measures are not widely applied in India yet. From 2011 to 2018, the Institute for Global Environmental Strategies (IGES) and The Energy and Resources Institute (TERI) jointly conducted 30 preliminary energy audits at different sectors including textiles, pharmaceuticals, automobiles, auto components, casting, and forging to promote energy efficiency of compressed air systems. Through this, it was found that there is a vast scope for energy savings by adopting better operating and maintenance practices, such as leakage prevention, pressure adjustment, air controls, improving ventilation, and installing appropriate compressors. Based on these findings, most of the audited companies incorporated the recommended operating and maintenance practices, and some installed new compressors. Information on energy efficiency is widely available in India; however, it was observed that companies, particularly small- and medium-scale enterprises (SMEs) had limited knowledge about it. To address this gap, authors carried out preliminary energy audits, organised awareness workshops, and trained energy personnel. This paper analyses the effect of these interventions and recommends actions to adopt a packaged approach to promote energy efficiency of the compressed air system in a more comprehensive manner.

Aditi Khodke, Toshizo Maeda, Girish Sethi, Mika Tachibana
Transformation Program for Low-Efficiency Electric Motors and Market Surveillance Activities in Turkey

“Industrial Energy Efficiency Action Plan” (IEEAP) within the context of the “Energy Efficiency Improvement Program” which is one of the primary transformation programs of the 10th Development Plan has been coordinated by the Ministry of Industry and Technology (MoIT). One of three key policy areas of this Action Plan outlines the goal of “increasing energy efficiency through transforming low-efficiency AC electric motors” for which MoIT has formulated national standards on electric motors following EU Commission Regulation (EC) No 640/2009 on electric motors.

Mevlüt Hürol Mete
The Public Energy Efficiency Policies Mapped and Implemented for the Industrial Motor Reconditioning Sector in Brazil

In 2001, Law 10,295 established the process to make mandatory the minimum energy performance standards (MEPS) in equipment that consumes a lot of energy. About 25% of Brazil’s electric energy is consumed by loads connected to industrial electric motors (IEM), making them the main targets of public policies of energy efficiency. Led by this law, decrees and ordinances were created for IEM, which raised the minimum nominal efficiency level of these motors from low efficiency class IR1 to those of class IR3, that took effect in 2019. IR1, IR2 and IR3 are Brazilian efficiency classes which have the same values for nominal efficiencies of IE1, IE2 and IE3, except for 7 cases in which smaller efficiencies are allowed for motors built in smaller frames. After regulating the market of new motors, it was necessary to understand the market of repaired/reconditioning motors (RM). In 2013, a study (Souza RC, Dantas BF, Reis D, Sant’Anna H, Calili RF, Fagundes WDC, Final report – market research on refurbished engines, a proposal for the regulatory agency. PUC-Rio, Rio de Janeiro, 2013) was accomplished to analyze it. At that time, a large resale market of RM was identified, in which these motors are less efficient and with a major impact on the country’s energy consumption. The number of motors repaired is much larger than the number of new motors. Also, the RM sector is unstructured, maintenance companies do not have a representative association with the government, do not have defined technical standards and, generally, the employees do not receive adequate training in how to maintain the motors. This work has been used by the Ministry of Mines and Energy to create two major measures: the formation of a working group and the inclusion of RM in the Interministerial Ordinance Joint of 2017, which established the efficiency class IR3 as MEPS. This working group has been promoting the energy efficiency in RM with actions implemented in six areas: sector identification including a new market study (Souza RC, Calili RF, Vieira RS, Teixeira RSD, Market research on refurbished engines, a proposal for the regulator, technical report for international cooper association. PUC-Rio, Rio de Janeiro, 2019), qualification / training, consumer awareness, standardization, representativeness creation and energy regulation. This chapter shows the implemented public policy, their results, earnings and barriers.

Rodrigo Santos Vieira, George Alves Soares, Rodrigo Flora Calili, Glycon Garcia Junior, Reinaldo Castro Souza, Carlos Aparecido Ferreira
Self-Assessment Tool for the Estimation of the Savings Potential of Electric Motor Systems

The industry and services sectors account for two-thirds of Switzerland’s total electricity consumption. Furthermore, a large portion of electricity consumption in the industry sector is attributable to electric motor systems. Several analyses were conducted during the past five years, and they all found that the savings potential lies between 20% and 30%. However, the companies still do not know the real savings potential of their electric motor systems. In view of this, several tools were developed in order to help them to assess it. This chapter presents a new all-in-one tool for the assessment of the savings potential of pumps, fans, compressed air systems and cooling compressors. Its design is such that companies can use it without assistance. If the data are available, the company can perform a more detailed analysis to increase the precision of the assessment by providing additional information, such as the ratio between the nominal power of the motor and the application (pumps, fans), the load profiles and the ratio between the nominal and maximum loads. Upon completion of this self-assessment, the company receives an estimation of the savings potential of its installations, as well as a list of basic efficiency measures to implement.

Richard Phillips, Yannick Riesen, Nicolas Macabrey
Labelling of Air Compressors – Much More Than Nameplate Data

Labelling of household appliances has been a success story by delivering information on energy consumption and the lifetime cost of operation of the appliances to private consumers. Energy efficiency labelling has triggered a boost of improvements. This paper addresses the difficulty of comparing energy efficiency data for air compressors, as the compressor manufacturers do not release them. The results demonstrate that a single energy efficiency value per compressor has only a limited value to identify the best product for the application. From the analysis and comparison of fixed speed and variable frequency drive air compressors, it is also demonstrated that compressors with variable frequency drive do not necessarily perform better than fixed speed compressors. The paper also stresses the importance of a compressed air system approach, being necessary to tap the largest energy-saving potentials in compressed air systems. The requirement to release complete data sheets of compressor packages sold in Europe similar to the USA is supported.

Peter Radgen
Theoretical and Experimental Evaluation of Compressed Air Leakages

The use of compressed air (CA) is common in almost every industrial sector and requires a significant share of the overall electricity consumption. Many studies have underlined the importance of energy efficiency in compressed air systems and have highlighted two key areas for the improvement of energy efficiency in compressed air systems, heat recovery and use and the reduction of air leakages. However, there is very little research so far on the quantification of air leaks and the effects and relations of leak configurations, pressures and air quality. The quantification of air leakages is still based on rather rough assumptions and calculations with a broad band of values and only few experimental evaluations.This chapter will describe the range of published leakage rates for predefined geometries and pressures, which shows deviations of up to 65%. Therefore, the calculation techniques and experimental setups of relevant publications are examined, highlighting their strengths and weaknesses. An improved and comprehensive simulation model for a detailed calculation of leakages will be presented. The model enables the user to vary a set of parameters (e.g. system pressure, system temperature, pressure dew point …) to gain a detailed understanding of leakage rates under different conditions.An experimental setup has been developed and commissioned. The setup allows the precise measurement of defined leakages. Experimental data are used to further improve and validate the simulation model. The chapter will present reliable data on leakage rates for standard geometries such as circular holes, based on high-precision measurements. The chapter will also describe the procedures how the artificial leakages are precisely manufactured and quality controlled. Encountered challenges will be discussed and the found solutions presented.

Manuel Unger, Peter Radgen
Digitalization in Electric Motor-Driven Systems

Digitalization can bring ‘smart’ applications to all kinds of industrial energy systems, of which electric motor-driven systems take the largest part of the industrial electricity use. Electric motor-driven systems (EMDS) are currently responsible for some 53% of global electricity consumption, and approximately 70% of the industrial electricity use (International Energy Agency: World Energy Outlook 2016, IEA Paris, 2016; Digitalization and the future of energy, DNV GL, 2019). An optimal interaction of the respective motor system components (motor control, motor, mechanical equipment and application) combined with digital technologies bring about large energy savings in operation. The ‘addition’ of digital solutions can enlarge the scope of optimization, including efficiencies in operating cost (flexibility, procurement, life cycle), energy, materials (circularity) and emissions.While it is already possible to seamlessly record energy data from components to enterprise level (MES systems) from the hardware and software side, the next step would be (automated) control of the system based on this analysis. This could be done by using all relevant data (for example, order situation, operating status, product quality and quantity, environmental conditions) in real-time resolution to operate the machines in optimal operating condition.The IEA 4E EMSA develops activities to conduct impact assessments of technology developments in the field of industrial digitalization. Interest is into identifying the potential impact and possible or needed policy measures to stimulate the development and implementation of digital technologies towards more efficient motor systems in industry. Examples of related digital technologies and products are sensors and big data analysis, decision tools and new testing tools. The application of digital twins and artificial intelligence will enhance energy and motor management and maintenance and systems efficiency strategies. First assessments indicate a significant contribution i.e. an improvement of energy efficiency of 20–25% and an increase of operational efficiency of 25%. The effects towards related policy areas with regard to capacity building, pilots and regulatory issues will be made.

Maarten van Werkhoven, Konstantin Kulterer
Calorimetric Efficiency Determination of Power Electronic Variable Speed Drives

A calorimeter test bench for the efficiency and power loss determination of power electronic variable speed drives is presented. The balanced calorimetric setup with air as the cooling medium is proposed to test small electronic drives for AC motors in a power range from 1 kW up to 7,5 kW. The construction, the required measurement equipment, the measurement procedure and especially the measurement results and uncertainty are important aspects of this test bench and are discussed in this chapter. The device under test is a 2,2 kW drive which is measured using both the input–output method and the calorimetric method. The test results are compared and conclusions are made concerning usability, repeatability and accuracy of the test bench. The overall goal is to further examine and optimize the calorimetric approach and to be able to obtain more accurate and comparable test results of very high efficient frequency converters. This setup reaches an uncertainty of ±2,39% or ± 1,48 W on the power loss at full load and speed using the calorimetric method.

Stan Caron, Arne Berteyn, Pieter Defreyne, Steve Dereyne, Kurt Stockman
Round Robin for Converter Losses: Uniform Testing Protocol and Results from Tests in Phase 1

Variable frequency converters (VFC) are becoming more and more important elements of an energy-efficient electric motor-driven system (EMDS). They help to adjust the speed and torque of the motor output to the required load of the application and thus are a major source of energy savings. On the other hand, a variable speed-driven system adds more cost and complexity, and the converter causes additional losses both in its own electronics as well as in the driven motor. The losses of converters for electric motor-driven systems have never been systematically and independently verified, as there are no consensus test standards on the subject. Following the publication of IEC 61800-9-2, edition 1, 2017 (IEC 61800-9-2, edition 1: Adjustable speed electrical power drive systems – Part 9–2: Ecodesign for power drive systems, motor starters, power electronics and their driven applications – Energy efficiency indicators for power drive systems and motor starters, Geneva, Switzerland, 2017), the need for a more robust testing protocol and repeatable results of tests from independent laboratories emerged and was recognized both by 4E EMSA (IEA Technology Collaboration Programme on Energy Efficient End-Use Equipment (4E), Electric Motor Systems Annex (EMSA)) and IEC SC 22G WG18 (IEC, Subcommittee (SC) 22G for Adjustable speed electric drive systems incorporating semiconductor power converters, Working Group (WG) 18 for Energy efficiency of adjustable speed electric power drive systems).Also, the move by the European Commission to introduce in 2019 Minimum Energy Performance Standards for converter losses in the draft for the revision of the Ecodesign regulation no. 640 for motors (European Commission (EC), Commission Regulation No. 640/2009 of 22 July 2009 implementing Directive 2005/32/EC of the European Parliament and of the Council with regard to ecodesign requirements for electric motors, Brussels, Belgium, 2009) stimulated the research effort. Four independent labs (CalTest/Australia; DTI/Denmark; BFH/Switzerland and Advanced Energy/USA) agreed to team up for this project, financed by the four respective governments. Phase 1 of the Round Robin project started by the end of 2017 through early 2019. The goal of the project was to define/refine a proposed test method, known as Uniform Testing Protocol (UTP) and a Standard Reporting Format (SRF). By testing a number of converters, the project expected to provide a first feedback on the validity of the reference losses of the IEC standard.The phase 1 report of March 2019 (Agamloh E., Baghurst A., Brunner C.U., Nielsen S.B., Vezzini A., EMSA IEC WG 18, Round Robin of Converter Losses, Report of Results of Phase 1, Zurich, Switzerland, March 2019. Available at: [8] shows the results of 58 tests on nine converters between 0.75 kW and 11 kW. It documents excellent agreement of the results for losses and efficiencies. Between the four laboratories a high level of repeatability was achieved, despite the fact that 24 different load motors were used in the tests. The newly defined UTP testing methodology includes the precise definition of the product under test and its auxiliaries (filters, cooling fan, etc.), the selection of the nominal output current (rated or adapted to motor), the status of the converter (out-of-the-box, no automatic self-test run), the type and size of cabling and the preferred characteristics of the load motor (size vs. converter, rated current, IE-class, pole number, etc.). After the completion of phase 1, the UTP was updated with lessons learned into a new version (UTP2). About 60 converters are planned to be tested in phase 2 (Nielsen SB, Vezzini A, Preliminary results from (RR’C) round robin for converter losses, phase 2, in EEMODS’19 conference proceedings, Tokyo, Japan, 2019) from 2019–2020 [9]. With the updated UTP2, a sufficient quantitative data will be made available to WG 18 to revise the reference losses in IEC 61800-9-2, which are widely seen as too high. Eventually, also the efficiency classification can be revised in an edition 2 of the standard, which is planned for 2021 publication.

Conrad U. Brunner, Emmanuel Agamloh, Andrew Baghurst, Sandie B. Nielsen, Andrea Vezzini
Preliminary Results from RR’C 2: Round Robin for Converter Losses, Phase 2

In the context of the revision of IEC 61800-9-2:2017 (IEC 61800-9-2, edition 1, Adjustable speed electrical power drive systems – Part 9–2: Ecodesign for power drive systems, motor starters, power electronics and their driven applications – Energy efficiency indicators for power drive systems and motor starters, Geneva, Switzerland, 2017) and the publication of an upcoming edition 2, several issues around converter losses need to be clarified. The testing method itself have been proven ambiguous as well as the reference losses which have been defined 5 years ago based on a simulation model that eventually appeared in a CENELEC standard EN 50598-2:2015 (CENELEC EN 50598-2, Ecodesign for power drive systems, motor starters, power electronics & their driven applications – Part 2: Energy efficiency indicators for power drive systems and motor starters, Brussels, Belgium, 2014). These values have never since been verified by actual tests of market products from different manufactures. The current test method has never been described in enough detail nor verified by independent test labs.On its meeting on 6 September 2017 at EEMODS’17 in Rome, representatives from IEC WG18 (IEC, Subcommittee (SC) 22G for Adjustable speed electric drive systems incorporating semiconductor power converters, Working Group (WG) 18 for Energy efficiency of adjustable speed electric power drive systems), 4E EMSA (IEA Technology Collaboration Program on Energy Efficient End-Use Equipment (4E), Electric Motor Systems Annex (EMSA) (European Commission (EC), Commission Regulation No. 640/2009 of 22 July 2009 implementing Directive 2005/32/EC of the European Parliament and of the Council with regard to ecodesign requirements for electric motors, Brussels, Belgium, 2009)) and several independent testing labs (“project group”) decided to have 4E EMSA to undertake the project leadership and the organization of a round robin exercise for converters cooperation with IEC WG18.Subsequently the round robin testing program for converter losses (RR’C) was established to serve as scientific base for establishing both a secured testing method and the necessary data base for converter losses through the entire range of 0.12 kW to 1000 kW that can be implemented in the coming revision of IEC 61800-9-2.In Phase 1 (from November 2017 to February 2019) the main goal was to establish a testing method that would be both accurate and repeatable and that would be practical for industry and research testing labs. The “Uniform Testing Protocol” (UTP) has been made available as ed. 2 by November 2018. Phase 1 was completed, and the final report discussed during the IEC SC22G WG18 Meeting in Melbourne, Australia (19–21 February 2019). Phase 1 results will be published in a separate paper at EEMODS’19 (Agamloh E, Baghurst A, Brunner CU, Nielsen SB, Vezzini A: EMSA IEC WG 18, Round Robin of Converter Losses, Report of Results of Phase 1, Zurich, Switzerland, March 2019. Available at ).In Phase 2 (from May 2019 to December 2020) the main goal is to validate the adapted testing method as well as establish a sufficiently wide data base of testing results over the entire range of converters between 0.12 kW to 1000 kW. In phase 2 the testing method shall also be verified in terms of “alternative” converter types such as active frontend converters.This chapter shall report intermediate results of the current status of RR’C phase 2 – Converter losses.

Andrea Vezzini, Sandie B. Nielsen
Embedded Estimation of Variable Speed Drive Input Current Distortion

This chapter addresses the estimation of the Total Harmonic Distortion (THD) of the drive input current, which is an interesting performance indicator of the variable speed drive. The analysis of the complete drive system is done (study of the dynamic model of the DC bus and its stability, frequency analysis of the input signals). A simplified estimator of the THD is proposed to be able to embed the calculation algorithm in real-time Drive control load with good accuracy and depending on the conduction mode of the DC choke (continuous or discontinuous).

Thomas Devos, François Malrait
Comparison of Fixed and Variable Speed Pumps Under Consideration of Manufacturer and Operator Aspects

Pumps are among the largest energy consumers in the industry and household sector. The operating point of a process is the decisive criterion for a plant operator when purchasing a pump system. To adjust the desired operating point of the pump, various methods are available. With the increasing number of variable speed drives, there is now another possibility to adjust the operating point. This study examines the effects of the use of variable speed drives on operators and manufacturers.For the operator, safe and energy-efficient operation of the pumps is particularly important. In order to carry out investigations here, a concrete application example is considered from the operators’ point of view. Two adjacent pump sizes are selected from a pump type series of a pump manufacturer and the smaller one is also operated with a variable speed drive. The measurement of these pump configurations shows that the variable speed operation of the pump is up to 6% more efficient than conventional operation.For the pump manufacturer, cost-efficient production and high product quality are important. With the help of variable speed drives, pumps can cover a larger operating area. This enables pump manufacturers to reduce their product range, which positively affects not only resource efficiency but also production and warehousing costs. In the application case it is shown that 71% of the pump sizes can be saved without any loss in efficiency.The conclusions elaborated in this study will help both plant operators and manufacturers to decide on the best way forward in terms of energy, resource and cost efficiency.

Sebastian Bold, Vincent Becker, Sven Urschel, Jochen Schaab
New Composite Containment Shell for Magnetically Driven Pumps

Ten years ago, Greene, Tweed & Co. successfully introduced a carbon-fiber-reinforced polyetheretherketon (PEEK) containment shell under the trade name Xycomp®, to serve the API 685 seal-less pump market (Weibel, Bieler, Magnetic-coupled pumps: the containment shell. EEMODS’09, Paper #46, 6 May 2009). Today, we introduce a new material called Xycomp® DLF (i.e., Discontinuous Long Fibers) for lower pressure rated shells, targeting the ANSI/ASME market. This new material offers the same high-service temperature of 180 °C (350 °F) at a significantly lower price. It was originally developed to serve the Aerospace market, where it sees a great success and market traction. Creating pump-shells from Xycomp® DLF was an obvious match, as it allows eliminating the eddy currents generated by current metallic shells, and therefore offers significantly higher safety in case of an upset condition such as fluid starvation and subsequent dry running. Compared to other non-metallic shells, such as those made from ceramics, Xycomp® is non-fragile, insensitive to thermal shock, and does not build up electrostatic charges. Its failure mode is well understood and highly predictable as required for any Aerospace application.With current legislation requiring zero emissions when pumping fluids are identified as hazardous (e.g., carcinogenic, explosive, toxic), magnetically coupled pumps offer a reliable alternative to the expensive and maintenance-intensive, double mechanical sealed pumps. However, if a magnetically driven pump is lined with a metallic containment shell, the required power to drive the pump is increased due to the eddy current losses. To overcome the eddy current losses (15–25% for large pumps), additional power is needed, and it is not always available in existing buildings, leading to higher service cost. With Xycomp® DLF shells, the same power will be required to drive the impeller as a mechanically driven pump.This chapter presents the results of a large number of internal and field tests performed on many different Xycomp® shell sizes and pressure ratings, demonstrating the high reliability and advantages over other industry standard shells. Results include creep tests up to 204 °C (399 °F) for 10,000 h, statistical shell burst pressures from −196 °C to 200 °C (−320 °F to 392 °F), fatigue testing up to 36,000 cycles, dry running up to 12 min, sand erosion wear, pumped fluid temperature increase as a function of flow rate, thermal shock, fire burn through tests, thermal expansion, and impact resistance.

Nicolas Weibel, Samuel Stutz, Daniel Rougnon, Frederic Perrottet
Hydraulic System Optimization

There are considerable opportunities for increased efficiency in hydraulic systems that can be realized through demand-oriented control methods and use of energy-efficient components. Experiences from studies shows that in many cases, a potential of up to about 50% can be realized compared to conventional systems (isbn: 978-87-91326-11-0).The project has developed a concept for optimization of hydraulic systems based on latest technology in components and controls compiled in a demand-driven approach. The demand-driven approach to system optimization and methods including necessary registrations for energy optimization of existing and design of new hydraulic systems was developed in the project (Hydraulic system optimization, research project report (349-016)).Furthermore, a new, independent tool for optimization of hydraulic systems is developed based on the latest knowledge about the operation of hydraulic. The tool is built on knowledge from the well-known Motor Systems Tool (Motor Systems Tool: ) as algorithms for motors, frequency converters are used in the hydraulic systems tool. The hydraulic systems tool compares eight different system setups based on specific data for system requirements as hydraulic flow and pressure from the hydraulic-operated equipment.In addition to the tool mentioned above, a guide for the design of energy-efficient hydraulic systems was developed since experiences show that the interaction between the capacity of the hydraulic pump, the accumulation tank, and regulation of hydraulic pressure relative to the actual needs is essential to ensure optimal energy-efficient operation.The main results of the project are: Optimizing tool for hydraulic systems Design guide for hydraulic systems Draft handbook for hydraulics Reporting incl. identification of potentials by sectors and technologies The project was funded by public means from the Danish ELFORSK Program (ELFORSK program webpage: ) and by the participating companies lead by Danish Technological Institute.

Sandie B. Nielsen, Claus M. Hvenegaard, Otto Paulsen, Søren Draborg
Comparison of Different Methods to Determine the Per-Phase Equivalent Circuit Parameters of Three-Phase Induction Motors Using IEC Nameplate and Catalogue Data

The per-phase equivalent circuit (EC) of three-phase, squirrel-cage, induction motors (SCIMs) is used to simulate their performance and for example to set motor control parameters in variable-speed drives. In this chapter, a new method based on a stochastic approach is applied to determine the EC parameters of IE1-, IE2-, IE3- and IE4-class SCIMs on the basis of motor nameplate and catalogue data, and the simulated motor efficiency, power factor and current curves, as a function of slip, are compared to those obtained with two deterministic methods, namely, the IEEE 112 F/F1 standard method (traditional method), based on the no-load and locked-rotor tests, and the method proposed in (Bortoni’s method), based on the motor nameplate and catalogue data. The proposed method is relatively fast and may lead to better results when compared to the deterministic methods.

Fernando J. T. E. Ferreira, André M. Silva, Edson Bortoni
Experimental Study on Three-Phase Induction Motor Performance Under Supply Voltage Unbalance for Star and Delta Connections

In this chapter, an experimental study is presented comparing the performance of an induction motor under supply voltage unbalance at no-load and full-load, for star and delta connections. Using a programmable voltage source, one of the phase voltages that supplies the motor is reduced gradually down to 80%. Then, a comparison is made regarding the motor phase voltage and current deviations in relation to the nominal values. Moreover, the phase current deviations are used to estimate the winding temperature rise in the slots. Finally, for both connection modes, the maximum output shaft power for nominal temperature rise under unbalanced supply voltage is compared to the NEMA derating curve.

Fernando J. T. E. Ferreira, José Alberto, Edson Bortoni, A. T. De Almeida
Conserving Energy in Compressed Air System: Practical Case Studies from Indian Industry

India is the second largest market for air compressors, and the market is growing at a rapid pace. All reputed international compressor manufacturers have their presence in India. Air compressors are widely used by large, medium, and small scale industries. Most large industries usually get their compressed air system audited regularly to save energy. However, SMEs cannot afford to engage the services of energy auditors to identify energy-saving options in their compressed air system.The authors have extensive experience of providing technical consultancy to SMEs on optimisation of their compressed air systems. SMEs typically use air compressors ranging between 20 and 300 hp. (15–224 kW approx.). Optimisation of compressed air system requires trained energy auditors and technical personnel. Our experience of working with SMEs shows that there is lot of confusion among the users about proper selection and best operating practices of air compressors.Some of our experiences with regard to compressed air system optimisation among Indian SMEs are shared in the chapter. Our studies on screw compressors show that there are three major energy conservation opportunities in compressed air system, viz. leakages, unloaded power, and artificial demand. Out of these three options, leakage and unloaded power concepts, are relatively simple to quantify and correct through energy audit studies. Air leakages are very simple to locate using ultrasonic meters. Adoption of variable speed drives for under loaded air compressor will result in substantial energy savings.However, the concept of artificial demand is more difficult in terms of acceptability and hence initiating corrective action. A higher compressor pressure causes the whole system to produce, consume, and waste more air than necessary. The authors have conducted several on-site capacity building programs for SMEs and built their capacities on what should be the minimum acceptable pressure and the pressure drop in the compressed air lines. A simple algorithm has been developed by the authors for correcting the receiver and pipeline sizing and reducing the artificial demand. This method works more economical than flow controllers.The chapter discusses some of the conventional energy-saving methods such as plugging of air leakage and minimising unloaded power in compressed air systems. In addition, some of the new technological developments, such as permanent magnet motors and inlet cooling systems, are also discussed. A detailed case study of actual compressed air optimisation in an SME unit is also presented.

Padmanabh Nagarkar, Prosanto Pal
Optimizing Pump and Compressor Selection for Energy Efficiency Using True-Weighted Efficiency (TWE)

Energy efficiency is emphasized worldwide for motor-driven fluid-handling equipment including pumps, fans, blowers, and compressors. Energy production and consumption comes with financial and environmental costs, making energy savings an important aspect of the life cycle cost evaluation of the pump or compression system. True-Weighted Efficiency, or TWE, is a general purpose method to provide a single efficiency metric applicable to a machine operating under multiple operating conditions.The TWE method is derived from the first principles, based on useful fluid energy output compared to the energy input into the system. Generalized load profiles are used that include one or more control curves, multiple discrete operating points based on those control curves, and the time of operation at each operating point. This method is applicable to pumps, compressors, blowers, and fans operating at fixed or variable speeds, on/off operation, throttle control, or by-pass control.As background, the chapter includes a brief survey of legislation known as the Ecodesign requirements for water pumps, and more recently, the United States Department of Energy (DOE) legislation affecting the commercial sale of specific types of pumps or fans sold in the United States.In order to promote widespread use and understanding of TWE for commercial applications, this chapter provides a general outline of the theoretical method. The fundamental principles and governing equations are introduced along with a simplified TWE equation based on a specified load profile and weighting factors. Two case studies are provided illustrating the use of the TWE method for a pumping system and a turbocompressor. The studies reveal that the machine with the best design point efficiency is not always the best choice from a TWE and energy consumption perspective. The goal of the chapter is to promote broad understanding and use of this method to reduce energy consumption for pump and compressor applications (Chapter 55).

Trygve Dahl
Energy Efficiency in Motor Systems
Dr. Paolo Bertoldi
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