Performance Evaluation of a High-Torque Permanent Magnet Brake at Operating Temperature Based on Magneto-Thermal Coupling Method
Round 1
Reviewer 1 Report
This paper presents thermal-magneto coupling analysis based on 3-D finite element analysis. The coupled analysis shows more accurate thermal and brake force characteristics than one-way analysis.
Author should explain what is the originarity of this article. The presented coupled analysis is well-known in many electrical machines such as motors, generators, and transformers.
Many figures (images) are not understandable because their resolutions are very low.
Author Response
Replies are given in appendix “Reply to reviewer 1
Author Response File: 
Author Response.pdf
Reviewer 2 Report
In fig 2, the magnetic loops are not clear. Update the picture.
In the explanation of magnetic circuit, are loops I1, I2, I3 same as loops phi1, phi2, phi3? This should be made clear to understand the explanation given.
What does the picture on left near section 2.2 represent?
What is building theoretical in flowchart in Figure 3? Is it setting up the model in FEA tool or some mathematical model?
Figure 4 flowchart must be changed to understand clearly. For example, two steps in the first dotted box is performed under electromagnetic simulation, second dotted box denotes thermal simulation.
Also instead of "t" give it as time. Because "t" is not used anywhere else in the paper.
Include what is "H" in equation (7).
Check the sentences in the paper. There are two to three places where the sentences need to be corrected.
Color shades plots in Figs. 6, 8, 9, 10 are not clear. Legend and the shade distribution are not legible.
Check the explanation given for Fig 7 on comparing two curves and correct it.
Figure corresponding to fig 12 is not numbered correctly.
Pictures in Fig 13 and 15 are not clear.
Author Response
Replies are given in appendix “Reply to reviewer 2
Author Response File: Author Response.pdf
Reviewer 3 Report
The manuscript provides an implicit magneto-thermal model for a rotary brake mechanism using permanent magnets. The effect of the generated magnetic torque due to the changes in the temperature was addressed in the manuscript. The electromagnetic losses were included as a heat source in thermal analysis. An iterative process to reestimate the electromagnetic losses was proposed due to the temperature-dependent resistivity and permeability. The static torque and temperature distribution are then calculated implicitly using a coupled model and a non-coupled (one-way) model.
Overall the topic of the manuscript could be interesting. However, the delivery of the results, discussion, and structure of the manuscript does not have the quality to be considered a research article. The manuscript must be fully revised for English, typos, the quality of the figures, proper use of symbols in the equations, details of the simulations, model verification, and discussion.
Below are the details:
The literature review needs more work. It should also convince the readers about the novelty of the current work compared with the works that have been previously done. What is the novelty of this work? What are the significant aims of this research?
Line 75-126
Section 2.1 needs to better describe the structure design of the brake mechanism. The figures have not been properly discussed in the manuscript. Also, the figures are blurry and the spring mechanism in Fig 1.a is not clear.
On Figure 1
Fig 1 quality is not appropriate.
Fig 1a and 1c have never been discussed in the manuscript. Where in figure number 7 "Inner Yoke iron" is referring to?
Fig 2 quality is not appropriate and is not described the brake mechanism properly. Label the components of the brake
The authors have described the brake mechanism in Fig. 2. What does Phi1 in the manuscript refer to? Line 116 mentions Phi1. It seems to be the figure caption however the symbol has not been used in the figure. Also Phi2 and Phi3.
Symbol Phi was previously used to represent the magnetic circuit in section 2.1 and in section 2.2 is used to describe the copper wire diameter. Two different symbols should be used to avoid confusion.
Line 138 Correct: Hc is the "height" of the coil section.
Line 150 What does "One method" refers to? Please be consistent with the naming of the methods one possible naming could be "uncoupled method" vs "coupled method"
Line 150
The parameters mentioned in the figures or flow charts need to be explained either in the manuscript text or the corresponding caption. What does theta_w in Figure 3 refer to? Is this a temperature, relative temperature, etc? Any parameter or equation such as Eq. 7 needs to be defined before it is been used.
The thermal model needs to be defined before the discussion of the algorithms either in uncoupled (i.e. one-way) simulation or coupled simulation.
References for equations (7) through (12) are required.
Correct in Line 197 mu sub 0 is vacuum permeability.
Line 200 fix the caption Radius of brake
Line 202 Use a proper reference for the clutch torque equation in equation 11. This equation is valid only for the clutch with no wear (i.e. fully flat contact surfaces). Over time, there will be wearing in contact disks (with a new equation T = mu F 1/2 (R2+R1)) how this result could affect the simulation results as less torque is being able to be transferred?
Have the authors considered the effect of thermal contact resistance between the components? If yes, it should be mentioned in the manuscript.
Line 210
The authors showed finite element analysis results that have never been discussed in the manuscript. Prior to the results and discussion, the authors are expected to fully explain their implemented model.
What type of physics study has been used for the modeling (e.g. thermal, dynamics, magnetics)? What program has been used for the simulation, how is the simulation carried out and what are the important parameters in the simulation? Was the magneto-thermal simulation carried out in an explicit or implicit model needs to be explained.
Figure 12 does not exist as it has been referred to in the manuscript.
Figure 11 caption is duplicated.
What parameter has been selected for the coefficient of static friction how do temperature changes affect this coefficient?
The quality of all figures needs significant improvement many of the details are not clear in the manuscript figures.
Line 299 Please specify what "at different method" means.
Line 314 The authors have mentioned "in the previous chapter", what chapter do the authors referring to?
Line 320 Experimental setup is not clear. What experimentation and under what conditions have been obtained?
Line 342 The experimental result does not seem to reach a stable temperature for t > 5000 s, more time is required for the experimental results to make sure the curve will be flattened. The experimental results have a significant time constant difference compared with both numerical models, what are the causes of these differences? Explain the effects of unmodelled physics or under/overestimated parameters that could cause such a considerable difference.
The results and discussion section should explain the benefit of the proposed model. Possible ways of the model improvements and causes of the error in the model.
Author Response
Replies are given in appendix “Reply to reviewer 3”
Author Response File: Author Response.pdf
Round 2
Reviewer 1 Report
No comment
Author Response
Replies are given in appendix “Reply to reviewer 1（Round 2）”
Author Response File: 
Author Response.docx
Reviewer 2 Report
Color scales are not clear to understand the temperature rise in the model.
Correct heat source spelling, Name of the figure is not complete, in Fig 4
Under section 4.1, same explanation is repeated twice.
Temperature scales are not clear in Fig 6.
Flux density scales in Fig 8 and Fig 9 are not clear.
In Fig 13, Specify what are the inputs and outputs of "Control and collection" block.
Author Response
Replies are given in appendix “Reply to reviewer 2（Round 2）”
Author Response File: Author Response.docx
Reviewer 3 Report
The author's answers to the technical comments are appropriate. The content has been improved in the new revision. The quality of some figures has been improved and some were added.
Still, some improvements are required for the quality of the figures such as in Figure 13 or Fig 15.
Line 116 The symbols has been updated to I1, I2, and I3 however later in the manuscript (paragraph beginning in Line 247) the authors still used the old symbols Phi1, Phi2, and Phi3. Please read the entire manuscript carefully and make sure it is consistent.
There are some typos and grammatical mistakes. I highly advise this paper to be reviewed for English improvement.
Figure 4 Please correct "sourc" to "source".
Line 93 Change the "explosion diagram" to the "exploded view"
Line 148 Please fix the manuscript by removing the 计算 "analysis method".
Author Response
Replies are given in appendix “Reply to reviewer 3（Round 2）”
Author Response File: Author Response.docx
