Wikipedia talk:Articles for deletion/Copper in energy-efficient motors

Request to revise and reinstate article after correcting criticisms
''The following is posted here by Enviromet as per recommendation after a discussion with the deletion requester, Tigraan. Please provide your feedback after reading this post. Enviromet (talk) 14:32, 2 May 2016 (UTC)

I am the creator of “Copper in energy-efficient motors” that was deleted three weeks ago while I was on a remote excursion (in Nepal) and was unable to address the concerns that had been voiced. The two major criticisms of the article stated were a lack of peer-reviewed citations and an excess of context information. There was also a comment about an absence of cost comparisons.

There has been extensive research, development and peer-reviewed publications over the past 15 years on the use of copper in premium energy-efficient motors and in induction motors with die-cast copper rotors. A list of over 30 such articles is included below. This topic is considered to be a very important development by vehicular and motor engineers all around the world. Premium-efficiency motors are now helping to meet new energy efficiency standards. Induction motors with die-cast copper rotors have just in the past few years been incorporated into high-performance, hybrid and electric vehicles, such as Tesla’s Electric Roadster, Model S and Model X; Mercedes’ model B250e, and Oshkosh’s HEMMT severe-duty fleet of trucks for the U.S. Army. Other major automotive manufacturers (Toyota, BMW, and Nissan/Renault) are evaluating/testing or designing die-cast copper rotor motors for their future models.

Please let me know the process for revising and reinstating the article with peer-reviewed published citations, as appropriate, and with the background context eliminated. Cost comparison information is also included in the body of peer-reviewed references.

Sorry to take up space on your (Tigraan's) talk page, but just to demonstrate how active and important this subject matter is, a peer-reviewed and motor industry society publications list about the importance of copper in energy-efficient motors in included below (with abstracts to help clarify a few titles).

Sincerely, Enviromet (talk) 16:31, 1 May 2016 (UTC):

1)	U.S. Department of Energy; Office of Energy Efficiency & Renewable Energy; Die Casting Copper Motor Rotors;

2)	Sathishkumar, G.K., Vimalraj, N., Sivakumaran, T.S., and Paramasivam, A; (2015); Design and Fabrication of High Efficiency Squirrel Cage Induction Motor Using Finite Element Method; ARPN Journal of Engineering and Applied Sciences; Vol. 10, No. 4, March; ISSN 1819-6608; This paper presents the design and analysis of a die-cast copper rotor cage, to improve the efficiency of three phase induction motor used in industrial applications and also it describes the various factors affecting the efficiency of motor. The proposed copper rotor motor has better efficiency and increase in torque with minimum losses. An incremental difference in the efficiency is also discussed with different values of loads. Simulation has been carried out using Finite element Analysis (FEA) and experimental results are shown. Simulation and experimental results presented here demonstrates the feasibility of the copper rotor motor.

3)	Goss, James, Popescu, M. and Staton, D. (2012). Implications of Real-World Drive Cycles on Efficiencies and Life Cycle Costs of Two Solutions for HEV Traction: Synchronous Permanent Magnet Motor vs. Copper Rotor Induction Motor; SAE Electric Powertrain Technologies Symposium; 11 October; Stuttgart, Germany.

4)	Liang, Daniel, Yang, X., Yu, J, Zhou, V; (2012). Experience in China on the Die-Casting of Copper Rotors for Induction Motors; XXth International Conference on Electrical Machines (ICEM); pp. 256 – 260; Published by IEEE; ISBN: 978-1-4673-0143-5; DOI: 10.1109/ICElMach.2012.6349874;

5)	Dorrell, David G., Popescu, M., Knight, Andrew M., Evans, L., and Staton, David A. (2010). Comparison of Different Motor Design Drives for Hybrid Electric Vehicles, IEEE Energy Conversion Congress and Exposition; September; pp. 3352 – 3359; ISSN: 2329-3721; DOI 10.1109/ECCE.2010.5618318;  (requires subscription) or  (no subscription) This paper reports on a study to compare the performance of an interior permanent magnet drive motor (IPM), a copper cage induction machine (IM) and a switched reluctance machine (SRM). The paper illustrates that the permanent magnet motor is not the sole solution to specifying a drive motor for this application.

6)	Kirtley, J., Schiferl, R., Peters, D., and Brush, E., (2009). The Case for Induction Motors with Die-Cast Copper Rotors for High Efficiency Traction Motors; SAE Technical Paper; 2009-01-0956; doi: 10.4271/2009-01-0956.  ''This paper considers the application of die-cast copper rotor induction motors in the drive system of parallel gas/electric hybrid vehicles and compares performance in a realistic driving scenario to that of a permanent magnet motor where efficiency is substantially reduced by PM drag loss. It is concluded from this analysis that the induction machine has a substantial advantage because it can be de-excited when it is not producing torque, eliminating no-load rotational magnetic and electrical loss. Application of die-cast copper rotor traction motors in the hybrid drive system of the latest generation of large U.S. Army severe-duty trucks is then considered. Results of two different electric motor designs are presented, one with a cast aluminum rotor cage and one with a die-cast copper rotor cage. The copper die-cast rotor motor is shown to be 23% lighter and 30% smaller than the aluminum rotor machine.''

7)	Tudorache, T., Melcescu, L. and Petre, V. (2009); High Efficiency Squirrel Cage Induction Machines; International Conference on Renewable Energies and Power Quality (ICREPQ’09); European Association for the Development of Renewable Energies, Environment and Power Quality; This paper highlights the benefits of replacing the classical cast aluminum cage with a cast copper cage in the manufacture of future generation of high efficiency induction machines used as motors or generators. The numerical analysis carried out in the paper is based on a 2D plane-parallel finite element approach of the induction machine, the numerical results being discussed and compared with experimental measurements.

8)	Manoharan, Subramanian, Devarajan, N., Deivasahayam, Subbarayan M. and Ranganathan, Gopalakrishnan (2009); Review on Efficiency Improvement in Squirrel Cage Induction Motor by Using DCR Technology; Journal of Electrical Engineering; VOL. 60, NO. 4, pp. 227–236; ISSN 1335-3632; and  ''Induction motors account for approximately 50 % of the overall electricity use in industrialized countries. In the agricultural and commercial sectors also, power consumption by ac motors is quite substantial. On an average, the energy consumed by a motor during its life cycle is 60-100 times the initial cost of the motor. Therefore efficiency of the motor is of paramount importance both during selection and operation. Even small increase in efficiency improvement can make a big difference in energy savings with accompanying decrease in air contamination. High electrical conductivity of copper in the rotor structure of a squirrel cage induction motor can achieve a reduction in overall energy losses of around 11% – 19 % and a consequent increase in energy efficiency. This paper reviews the implementation of Die-Cast Copper Rotor (DCR) Motor, Efficiency improvement, Energy saving potential, adoption of DCR Technology in India and the comparisons of various efficiency standards besides the application of DCR motor in agricultural pump sets. The needs and tasks regarding the technology are also discussed. K e y w o r d s: induction motor, premium efficiency, efficiency improvement, die cast copper rotor, DCR technology, and efficiency standards.''

9)	Dyess, Nicole Kaufman and Agamloh, Emmanuel (2007). Copper Rotor Motors: A Step Toward Economical Super-Premium Efficiency Motors?; ACEEE Summer Study on Energy Efficiency in Industry; and  This paper presents the design and analysis of a die- cast copper rotor cage, to improve the efficiency of three phase induction motor used in industrial applications and also it describes the various factors affecting the efficiency of motor. The proposed copper rotor motor has better efficiency and increase in torque with minimum losses. An incremental difference in the efficiency is also discussed with different values of loads. Simulation has been carried out using Finite element Analysis (FEA) and experimental results are shown. Simulation and experimental results presented here demonstrates the feasibility of the copper rotor motor.

10)	Peters, D.T., Brush, E.F., Kirtlet, J.L., (2007). Die-cast copper rotors as strategy for improving induction motor efficiency; Electrical Insulation Conference and Electrical Manufacturing Expo (IEEE); 22-24 Oct. 2007; pp. 322 – 327; ISSN:2334-0975; DOI: 10.1109/EEIC.2007.4562636; ''This paper reviews the advantages of substituting copper for aluminum in the rotor squirrel cage as a central strategy toward reaching substantially higher efficiency. Short die life has discouraged production of copper rotors, but recent development of a heated nickel-base alloy die technology has solved the manufacturing problem; this is briefly reviewed. Copper rotor high efficiency motors are now commercially available. Performance characteristics of example motors are presented and design modifications employed to optimally utilize the high conductivity copper are outlined. Weight and cost savings realized by European manufacturers with high efficiency copper rotor motors compared to aluminum rotor designs with the same efficiency and performance characteristics are discussed. Applications for these motors in defense systems are now being examined for both 60 and 400 Hz equipment. Induction motors with copper rotors for traction also appear to have real advantages. Use of this motor type in the series hybrid drive system of a heavy duty Marine Corp truck is reviewed.''

11)	Kirtley, James L. Jr., Peters, Dale T., Cowie, J.G., and Brush, Jr., Edwin F. (2007); Improved Hybrid Vehicle Traction Motors Using Cast Copper Rotor Induction Machines; International Exhibition and Conference Ecological Vehicles and Renewable Energies, March 29-April 1; Monaco.

12)	Kimmich, R., Doppelbauer, M., Peters, D.T., Cowie, J.G. and Brush, Jr., E.F. (2006). Die-cast Copper Rotor Motors via Simple Substitution and Motor Redesign for Copper, International Conference Electrical Machines (ICEM 06), Conference Proceeding CD, No. 358; September; in Chania, Crete Island, Greece.

13)	Kirtley, J. L., Cowie, J. G., Peters, D. T., and Brush, Jr., E. F., (2006). Die-Cast Copper Rotors for Smaller High Efficiency Automobile, Traction Motors – A Design Study; SAE International; 07PFL-196; ; ''We consider drive motors for hybrid or electric vehicles. In particular, we explore the relationship between induction machines constructed with die-cast aluminum and copper rotors. Approximate size, weight and performance metrics are deduced for drive motors capable of 60 kW at 1,200 RPM. It is found that the use of a cast copper rotor can result in a drive motor that has an efficiency more than two percent greater than a geometrically similar motor with an aluminum rotor, or that a motor with similar efficiency can be made smaller and lighter than the aluminum rotor motor. A comparative cost analysis for the three induction motors is presented.''

14)	Zeraoulia, Mounir, Benbouzid, M.E.H., and Diallo, D., (2006). Electric Motor Drive Selection Issues for HEV Propulsion Systems: A Comparative Study; IEEE Transaction on Vehicular Technology; Vol. 55, No. 6; pp. 1756 – 1764; ISSN 0018-9545 ; DOI 10.1109/TVT.2006.878719; This paper describes a comparative study allowing the selection of the most appropriate electric-propulsion system for a parallel hybrid electric vehicle (HEV). This paper is based on an exhaustive review of the state of the art and on an effective comparison of the performances of the four main electric-propulsion systems, namely the dc motor, the induction motor (IM), the permanent magnet synchronous motor, and the switched reluctance motor. The main conclusion drawn by the proposed comparative study is that it is the cage IM that better fulfills the major requirements of the HEV electric propulsion.

15)	Kimmich, R., Doppelbauer, M., Kirtley, Jr, J. L., Peters, D.T., Cowie, J.G. and Brush, Jr., E.F., (2005). Performance Characteristics of Drive Motors Optimized for Die-cast Copper Cages, Energy Efficiency in Motor Driven Systems (EEMODS 2005); Fourth International Conference; September; in Heidelberg, Germany;  (pp. 110-117) Performance of a series of industrial drive motors designed expressly for high conductivity copper in the rotor cage is described. These motors are to replace a series of standard efficiency aluminum rotor models. Efficiencies of the copper designs meet the EFF 1 targets and are generally less expensive to build and lighter than aluminum rotor designs modeled but not built. An example of the use of MATLAB software to optimize a motor design feature, the effect of rotor skew on stray load loss, is presented.

16)	Parasilliti, F., Villani, M., and Chiricozzi, E. (2005). Design Strategies and Different Materials for High Efficiency Induction Motors: A Comparison, Energy Efficiency in Motor Driven Systems (EEMODS 2005) Fourth International Conference, September; in Heidelberg, Germany. (pp. 69-80). The paper presents the results of a research project concerning the efficiency improvement in industrial three-phase induction motors, making use of three different design strategies: substitution of copper cage for aluminum cage with standard and premium electrical steel; design optimization of copper cage motor by changing the stator winding and the stack length only; design optimization of copper cage motor by changing the stator winding, the stack length and the stator and rotor slot shapes.

17)	El-Refaie, A.M., Jahns, T.M. (2005). Comparison of Synchronous PM Machine Types for Wide Constant-Power Speed Range Operation, IEEE Industry Applications Society Annual Meeting, Hong Kong, October; pp. 1015 – 1022, Vol. 2, ISSN 0197-2618; DOI 10.1109/IAS.2005.1518478 ''This paper presents a detailed comparison of the high-speed operating characteristics of four synchronous PM machines for applications that require wide speed ranges of constant-power operation. These machines include surface PM machines with both distributed and fractional-slot concentrated windings, and two interior PM machine with distributed windings. These two versions of the interior PM machine include one with and a tight constraint on the machine's back-emf voltage at top speed and one without this constraint The target application is an automotive direct-drive starter/alternator requiring a very wide 10:1 constant power speed ratio (CPSR). Detailed comparisons of the performance characteristics of the machines are presented that include important issues such as the back-emf voltage at top speed, machine mass and cost, and eddy current losses in the magnets. Analytical results are verified using finite element analysis (FEA). Guidelines are developed to help drive designers decide which type of machine is most suitable for high-CPSR applications. Tradeoffs associated with choosing each of these machines are presented.''

18)	Hsu, J.S, S.C. Nelson, P.A. Jallouk, C.W. Ayers, R.H. Wiles, S.L. Campbell, C.L. Coomer, K.T. Lowe, T.A. Burress (2005). Report on Prius Motor Thermal Management, Oak Ridge National Laboratory Report ORNL/TM-2005/33;

19)	Stark, C., Cowie, J. G., Peters, D. T. and Brush, Jr., E. F. (2005); Copper in the Rotor for Lighter, Longer Lasting Motors; ASNE Fleet Maintenance Symposium; San Diego Section; September; ''This paper reviews the advantages of substituting die-cast copper for aluminum in the motor rotor. This advance in motor technology has been long sought by the motor industry but short die life due to the high melting point of copper frustrated attempts to manufacture by pressure die casting. The nickel-base alloy hot die technology developed to solve the manufacturing problem is briefly reviewed. Development work done prior to the present program and commercial motors derived from that work have focused on the increased electrical energy efficiency achievable by using copper with its higher electrical conductivity in the rotor. Performance characteristics of example industrial motors are presented. Modification of the conductor bar shape to control in-rush current and starting torque to accommodate copper in the rotor will be discussed. Modeling by motor manufacturers has shown that by using copper in the rotor, a lighter motor than an aluminum rotor motor at the same efficiency can be built. An example of weight savings calculated for a 15 Hp (11 kW) motor is presented. Data presented here show that motors with copper rotors run cooler. Industry experience shows that cooler operation translates to reduced maintenance costs, improved reliability and longer motor life.''

20)	Peters, D.T., Cowie, J.G., Brush Jr., E.F., et. al., (2005). Performance of motors with die-cast copper rotors in industrial and agricultural pumping applications; IEEE International Conference on Electric Machines and Drives. pp. 987 – 992; ISBN 0-7803-8987-5; This paper adds to the growing body of data showing improved efficiency and cooler running temperatures for copper rotor motors. Test data for motors where copper has simply been substituted for aluminum with no change in design are presented for a series of motors built in India for pumping water for agriculture and two industrial motors are described. Design modifications to better utilize copper in the rotor and resulting motor performance for two other industrial motors are then reported.

21)	Kirtley, James L. (2004). Designing Squirrel Cage Rotor Slots with High Conductivity; This paper describes an investigation into ways of taking advantage of the higher conductivity of cast copper in rotors of induction motors. Deep bar and multiple cage effects are useful in design of such machines. It is shown that a useful understanding of how different slot shapes work may be developed through the use of frequency response curves that describe rotor slot impedance as a function of rotor frequency. Good starting, running and stray loss characteristics can be identified in such frequency response curves.

22)	Chiricozzi, Enzo, Parasility, F. and Villani, M. (2004). New materials and innovative technologies to improve the efficiency of three-phase induction motors. A case study; ''The paper presents the results of a research project whose aim was the investigation of the efficiency improvement of industrial three-phase induction motors when high quality electrical steel is adopted in combination with die cast copper rotor cage, in order to define the design strategies; to verify the actual efficiency improvements; to verify the arrangement of the motors respect to the European Classification Scheme (EC-CEMEP). The results are related to the cheapest design strategies when "premium steel" and copper rotor cage are used instead of standard steel and aluminum cage, with standard and higher stack length. The considered motor sizes are 3 and 7.5 kW, 4 pole, 50 Hz, 400 V, TEFC.''

23)	Parasiliti, F., et. al., (2004). Three-Phase Induction Motor Effficiency Improvements with Die-Cast Copper Rotor Cage and Premium Steel; Symposium on Power Electronics, Electrical Drives, Automation and Motion (Speedam); June 16-18, Capri, Italy. The paper presents the results of a research project whose aim was the efficiency improvement in industrial three-phase induction motors, making use die cast copper rotor cage and premium electrical steel. The study concerns with industrial low voltage three-phase induction motors, 4 pole, 50 Hz, 400 V, TEFC, in the 0.75÷22 kW power range. The results are related to the first step of the project, when a premium steel and copper rotor cage have been used instead of standard steel and aluminium cage.

24)	Brush, Jr., E. F., Peters, D.T., Cowie, J.G., Doppelbauer, M. and Kimmich, R. (2004). Recent Advances in Development of the Die-cast Copper Rotor Motor, International Conference Electrical Machines (ICEM02), In: Recent Developments of Electrical Drives: Best papers from the ICEM’04; pp. 349-359; September; in Krakow, Poland. DOI: 10.1007/978-1-4020-4535-6_29; ISBN: 978-1-4020-4534-9 ''Performance of several motors where copper has been substituted for aluminum in the rotor squirrel cage is reported. Copper rotor motors die cast in India for agri-pumping were dynamometer and field tested. Copper rotors resulted in higher electrical energy efficiency, slightly higher rotational speed, lower operating temperature, and higher pumping rates and volume pumped per unit of input energy. SEW-Eurodrive motors with copper rotors are also described. A 1.1 kW motor with copper simply substituted and a 5.5 kW motor with redesigned rotor and stator are described. The copper rotor reduced losses in all major categories. Full-load efficiency was increased 6.7 and 3.1 percentage points, respectively. Finally, a study to minimize formation of large pores in die-cast rotors is summarized.''

25)	Ayers, C.W., J.S. Hsu, L.D. Marlino, C.W. Miller, G.W. Ott Jr., C.B. Oland (2004). Evaluation of 2004 Toyota Prius Hybrid Electric Drive System Interim Report; Oak Ridge National Laboratory Report ORNL/TM-2004/247.

26)	Brush E.F.; Cowie, J.G.; Peters D.T.; Van Son D.J. (2003). Die-Cast Copper Motor Rotors: Motor Test Results, Copper Compared to Aluminum, in. “Energy Efficiency in Motor Driven Systems”, Editors: F. Parasiliti, P. Bertoldi, Springer, pp. 136 –143, ISBN 3-540-00666-4.

27)	Parasiliti, F. and Villani, M. (2002). Design of High Efficiency Induction Motors with Die-casting Copper Rotors; Proceedings of Energy Efficiency in Motor Driven Systems (EEMODS 2002) Third International Conference; Treviso, Italy. pp. 144-151; The paper deals with the use of copper cage in three-phase low voltage induction motors and gives a design guideline to optimize their efficiency, according to the new European classification scheme. An accurate motor design allows to “move” the motor from lower to upper efficiency classes without affecting the starting performance.

28)	Peters, D.T. et. al., (2002). Use of High Temperature Die Materials and Hot Dies for High Pressure Die Casting Pure Copper and Copper Alloys, Trans. of the North American Die Casting Association, Die Casting Congress, Rosemont, IL, USA.

29)	Peters, D.T. et. al., (2002). Advances in Pressure Die Casting of Electrical Grade Copper, American Foundry Society Paper; No. 02-002, Kansas City, MO, USA.

30)	Paris, C. and Walti, O. (2002). A New Technology to Make Rotors with Copper as Magnetic Conductor, Trans. of the Energy Efficiency in Motor Driven Systems Conference; p. 152-161. DOI: 10.1007/978-3-642-55475-9_23; ISBN 978-3-540-00666-4; by Springer-Verlag Berlin Heidelberg; Our study aims at showing a new technology to make rotors with copper as magnetic conductor. It deals with copper’s pressure die-casting rotors production. It will be very interesting also to compare these new technology to the usual to make rotors with copper as magnetic conductor; but also to study the electromagnic’s behaviour of the copper die-casting rotor in comparison with the aluminium technology.

31)	Finley, William R., and Hodowanec, Mark M. (2000). Selection of Copper versus Aluminum Rotors for Induction Motors; IEEE Transactions on Industry Applications; Vol. 37; Paper No. PCIC-2000-19; IEEE/PCIC Conference Record; pp. 1563-1573; ISSN 0093-9994; DOI: 10.1109/28.968162 ; by IEEE Industry Applications Society. ''On squirrel-cage induction motors, there is an important choice between utilizing a lower cost die-cast or fabricated aluminum rotor versus the more expensive copper bar rotor. Utilizing the wrong rotor construction for the application can either increase costs unnecessarily or lead to catastrophic failure. This paper provides the background necessary to assist in making the proper choice. The fundamentals of rotor construction and basic information on how the induction motor works are discussed. Additionally, the effects of various materials and types of rotor construction on motor performance are analyzed.''

Enviromet (talk) 14:32, 2 May 2016 (UTC)


 * Comment by nom I was contacted by the page creator on my TP, and advised them to start the discussion here. Not sure that is best, but certainly WP:DRV is inappropriate for content discussion, and rewriting the article outright without having had wider input is certainly not a good idea. Do suggest a better venue if you have an idea.
 * The original article, which was deleted, was in my view inacceptable on WP due to the breaching of several guidelines. However, being a bad article is not in itself grounds for deletion. The question is whether "copper in energy-efficient motors" is a suitable topic.
 * Based on the search I made before nominating, I found two reasons (the first one possibly surmountable) with this:
 * Few independent sources exist to write the article (the relevant policies are WP:RS, WP:NPOV, and possibly WP:COI), so the risk of doing original research are big. Even though claims made by non-independent sources may be unquestionably true, e.g. "copper's electric conductivity is higher than aluminum's", the order in which true facts are presented may be tendencious. For example listing all the advantages of copper without mentioning drawbacks leads the reader to the conclusion copper is "better" in every possible sense. If you do not see the risks of "saying only true things", imagine that someone went to the asbestos page and removed all material alluding to its carcirogenic properties. All remaining statements would still be true, precise and sourceable; nonetheless, the result would be an awfully misleading page presenting a material with fantastic properties that governments decided to ban for no reason.
 * The big problem to my eyes is notability. I see exactly one source (the IEA report) that simultaneously (1) deals with the subject in some detail, (2) is reliable, and (3) is independent. Emphasis on (1); the subject is not "copper", nor "motors" or "electric motors", nor "energy efficiency"; it is copper, used as a material for electric motors. One may say that it is hardly a wonder that this very specific subject is rarely mentioned, but that is only saying that it is not notable, and appropriate content should be merged to parent articles such as Electric motor.
 * I must also say that the surmountable problems were not very encouraging: the bombardment of references, the POV content ("copper be good") and title ("copper in electric motors" would better IMO), the essay-like style... I appreciate that created the article in good faith, and one IEA report is much more notability than the average notability-failing AfDed article. But I see no compelling reason to not stick with "significant coverage in multiple independent reliable sources".  Tigraan Click here to contact me 15:47, 2 May 2016 (UTC)

Submission for Review and Reinstatement
This article was posted and available on Wikipedia for 5 years. It was amended and linked to other articles by various editors and contributors since that time. A criticism was made in April 2016 that the article lacked peer-reviewed references and contained too much background material. After much work, all concerns were carefully addressed and corrected. This revised article is focused on copper conductors, on new copper technologies for premium efficient motors, it is now fully referenced with peer-reviewed citations in professional journals, and regulatory background material deemed unnecessary by others was deleted. This revised article is now ready for review and consideration for reinstatement as very useful information to those concerned about the electrical energy efficiency of motors.Enviromet (talk) 17:15, 27 May 2016 (UTC)Enviromet (talk) 16:49, 27 May 2016 (UTC)