Thermal Analysis of a Modular Permanent Magnet Machine under Open-Circuit Fault with Asymmetric Temperature Distribution

Round 1

Reviewer 1 Report

The topics of the paper are in line with the themes of the journal. Undoubtedly, the strength of the manuscript is the combination of experimental studies and numerical simulation. However, there are numerous editorial and factual errors in the paper. The lack of a description of the test stand and analysis of measurement errors makes it impossible to reproduce the experiment and verify the results obtained by the authors by other researchers. In addition, the results of analysis and research are not fully substantively described. In my opinion, the manuscript in its current form requires significant additions and corrections, which should be eliminated before publication. I have included a list of my most important comments that should be addressed by the authors below.

 

 

1. The Abstract section should include the most important qualitative and quantitative results of the analyses performed by the authors. Please improve this.

2. The "Introduction" section should include the most important qualitative and quantitative results of studies cited from the literature. Please improve this.

3. In the summary of the "Introduction" chapter, emphasize the novelty and originality of the work and what literature gap is filled by the manuscript presented by the authors. Please correct this.

4. The description of the engine model is insufficient. Among other things, the basic geometric dimensions in Figure 1 are missing. Please correct this.

5. I recommend creating a "Nomenclature" section, which should include all symbols and abbreviations used in the manuscript. If possible please add units.

6. In Table 1, only thermal conductivity is given and the names of the structural materials involved are missing. Please supplement this.

7. On page 4, line 132, the authors wrote "rotation speed of the machine is very low". What does this mean? State what the rotational speed was. Do not use such general wording in a scientific article just give a specific value. Please check the manuscript for this.

8. In Section 2.2, state the boundary conditions for which the numerical analysis was performed.

9. In Figure 5, mark the directions of the x,y,z axes. Give the names of the vertical axis and the units. Please complete this.

10. The factual description of Figure 5 is insufficient. No analysis of the results obtained. Please supplement this.

11. On page 7 in line 194 the authors wrote "heat transfer resistance is large". What does this mean? Do not use such general wording in a scientific article just give a specific value. Please again to check the manuscript for this.

12. In Figure 6, mark the directions of the x, y, z axes. Give the names of the vertical axis and the units. Please complete this and check the manuscript for this.

13. Poor quality of figure 7. Please correct this.

14. Poor quality of figure 10 and figure 11. Please correct this and check the manuscript for this.

15. Chapter 4 lacks a description of the test bench and its components.

16. Provide a list of test apparatus and measurement sensors used in the study. This could be presented, for example, in a table, stating: sensor type/model, manufacturer, measurement range and measurement error. Please complete this.

Author Response

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Author Response File: Author Response.pdf

Reviewer 2 Report

The relevance of the work stems from the need to develop more and more powerful and compact electric motors with high fault tolerance. High heating of such engines is a significant problem, the solution of which is an urgent scientific and technical problem.

 

An important positive aspect of the work is the experimental verification of the performed calculations, which proves the reliability of the results obtained, as well as the possibility of their practical application.

The main negative point is the inconsistency in the setting of goals, the work performed and non-specific conclusions. As a result, the article requires significant revision.

 

1. In the literature review, fairly new information was used, judging by the list of cited publications. At the same time, the review itself is written superficially.

2. The second section describes the mathematical model and methods for modeling temperature in the device under development.

3. The third section presents the results of modeling and temperature calculations.

4. The fourth section presents the results of experimental verification of the performed calculations and approbation of the developed equipment.

 

With regards to 2-4 sections. The description of the results and illustrations are generally well done. At the same time, there are minor flaws that can be found in the comments.

 

5. The discussion is written as an abstract of the article. This section needs to be completely reworked.

6. The conclusions are written in general terms and do not specifically quantify the main results, although it would be easy to do so based on the results.

 

Remarks

1. From its content of the introduction (section 1) there is no clear understanding of the problem the authors are working on. It simply lists some results that are known, but without further explanation of the need for ongoing research. The final part of the review contains an abstract description of the work performed. The purpose and objectives of the study from the introduction are not clear. Instead, they are formulated in section 5 (discussion).

2. In Section 5 there is no discussion of the new results obtained. There is also no information on comparing the obtained results with known literature data. In its current form, this section does not correspond to the generally accepted idea of a scientific publication.

3. Description and arrangement of illustrations in section 4 should be corrected. I recommend combining figures 13-15. This will allow the reader to better understand what device the stator is part of. Also, I don’t think that someone cares about the wiring diagram for the rotor.

4. Not all abbreviations are deciphered. For example, EMF.

5. You should check the signatures and inscriptions on the figures. They contain typos.

6. The authors declare as one of the goals of the work "determination of the output moment". However, the text does not provide specific torque values. This is also not reflected in the findings. A comparative assessment of the calculated and experimentally measured temperatures is not reflected.

Author Response

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Author Response File: Author Response.pdf

Reviewer 3 Report

The novelty of the paper is in a thermal analysis of a new modular permanent magnet machine in a normal mode and under open circuit fault. The paper can be published not only because of its novelty but also because the description of the thermal analysis could be interesting for the specialists beginning their simulation of electric machines. But first, the paper must be improved and extended.

1) Please, correct typos such as ‘Wingding’ in Table 1.

2) What is the alpha value (the equivalent heat dissipation coefficient) and how was got?

3) Add some explanation of how the expression (2) is used. How was hi value got, in which direction must the thickness be considered? For example, a circular wire is covered with insulation in any direction. Provide hi values of all insulation types. You mentioned the paint film insulation of the wire only in the text, provide its thermal conductivity in table 1. In short, everyone must be able to repeat the calculation under (2).

4) Add some words about the core loss calculation.

Author Response

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Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

The authors answered my questions and made the necessary corrections to the manuscript. In my opinion, the revised manuscript can be published.

Reviewer 2 Report

The authors took into account the main comments and made corrections to the text and graphics.