Service Life Prediction for Rotating Electrical Machines on Aircraft in Terms of Temperature Loads
, Justyna Tomaszewska 2, Mariusz Michalski 2 and Krzysztof Kordys 3Round 1
Reviewer 1 Report
A. Drafting errors
1. Row 107-108 missing reference at Transport aircraft M-28
2. Idem row 117
3. Idem row 142 at C-130 Hercules
4. Idem row 154
5. Idem row 322
6. Idem row 356
7. Idem….. all paper
B. Copy-paste from other material (ex.row 174 Gas turbine " The air used to power the ATM comes from a Gas Turbine Compressor/GTC, figure 30, or from external sources"
C. Unclear
In the analyses of the failure models for electrical machines, two competing models were selected, bearing failures and a model that handles with winding failures. The models also take low temperatures ( -38 °C) into account where the lubricant loses its performance and approaches a solid state .
· Is unclear how was calculated operating time t from formula (5)
· Is unclear where and how it was determined bearing life of an electric machine with relation(1). The basic rating life of a bearing in accordance with ISO 281 have other relation
· Is unclear where and how it was determined durability of an electrical machine winding.
Comments for author File: 
Comments.pdf
Author Response
Dear Reviewer,
firstly, I would like to thank you for investing the time to read our article and for all your valuable comments. We put our explanation below your comments (red).
Copy-paste from other material (ex.row 174 Gas turbine " The air used to power the ATM comes from a Gas Turbine Compressor/GTC, figure 30, or from external sources"
corrected, we also corrected other spelling mistakes and gave our article to profesional English correction.
In the analyses of the failure models for electrical machines, two competing models were selected, bearing failures and a model that handles with winding failures. The models also take low temperatures ( -38 °C) into account where the lubricant loses its performance and approaches a solid state .
Based on an analysis of bearing failure data for electric machines, it appears that most failures occur at temperatures around -38 o C, which may be related to the grease losing its lubricating properties.
Is unclear how was calculated operating time t from formula (5)
Is unclear where and how it was determined bearing life of an electric machine with relation(1). The basic rating life of a bearing in accordance with ISO 281 have other relation
Determining the reliability of electric machine bearings in the method presented here involves taking into account the ambient temperature. The model for predicting bearing life was developed based on data collected from electric machine operating companies. The distribution coefficients were determined by the empirical method of fitting functions to measured data. The linear regression technique was used to fit the coefficients in the developed method.
Is unclear where and how it was determined durability of an electrical machine winding.
The determination of winding reliability just as in the case of bearing reliability takes into account the ambient temperature.
Best regards,
on behalf of coauthors Justyna Tomaszewska
Reviewer 2 Report
1) In line 83, the frequency measurement unit is written incorrectly - HZ instead of Hz.
2) In lines 107 - 108 appears the phrase Error! Reference source not found.. Unfortunately, this is repeated many times in the work: - lines 117-118; - line 142; - line 154; - line 322; - line 356; - lines 359-360; - line 376; - line 382; - lines 388-389; - line 402; - lines 407-408; - line 414; - line 419; - line 421.
3) There are other punctuation mistakes and non-compliant notations:
- the bracket left open in line 128;
- the mention of a figure 30 (probably from another work) in line 174;
- additional point in the explanation of figure 6;
- the use of a notation with figure 1 in line 381 when it should have been figure 9;
- the a priori non-explanation of the time unit from relations (6) and (10).
Additional: - providing details on the models used; - the clear specification of the method of determining the average value of the operating time based on the data in table 3 (arithmetic mean, geometric mean and why?); - how to explain, however, the discrepancies between the values calculated in the paper and the manufacturers' recommendations?
Author Response
Dear reviewer,
firstly, I would like to thank you for investing the time to read our article and for all your valuable comments. We have posted the responses under your comments (red)
1) In line 83, the frequency measurement unit is written incorrectly - HZ instead of Hz.
corrected
2) In lines 107 - 108 appears the phrase Error! Reference source not found.. Unfortunately, this is repeated many times in the work: - lines 117-118; - line 142; - line 154; - line 322; - line 356; - lines 359-360; - line 376; - line 382; - lines 388-389; - line 402; - lines 407-408; - line 414; - line 419; - line 421.
Unfortunately I didn't check the pdf exactly, only the word file. That is why the problem appeared. I can only apologise and thank you for your comment.
3) There are other punctuation mistakes and non-compliant notations:
- the bracket left open in line 128;
- the mention of a figure 30 (probably from another work) in line 174;
- additional point in the explanation of figure 6;
- the use of a notation with figure 1 in line 381 when it should have been figure 9;
- the a priori non-explanation of the time unit from relations (6) and (10).
Before resubmission we gave our manuscript to professional English corrector. And corrected mistakes pointed by you.
Additional: - providing details on the models used; - the clear specification of the method of determining the average value of the operating time based on the data in table 3 (arithmetic mean, geometric mean and why?); - how to explain, however, the discrepancies between the values calculated in the paper and the manufacturers' recommendations?
The discrepancy between the calculated values and the actual value recorded in the aircraft operating documentation is due to the fact that the calculations are the maximum operating time of the machine, while in the process of aircraft operation the values that allow to perform the aviation task safely are adopted. Therefore, periodic inspections are performed to extend the process of operation of the electric machine.
Best regards,
on behalf of coauthors Justyna Tomaszewska
Reviewer 3 Report
The topic of this article is intresting. However, the format of the manuscript is too arbitrary,which seems not an academic paper. The PDF format has many alarts like "presented in Error! Reference source not found" . And there are many sentence like that on line 19 “Due to the difficulty of measuring the wear of bearings as well as windings of an electric machine, the dependence of bearing and windings on the ambient temperature by replacing the flight altitude by temperature. ” By the way, the abbreviations like APU and GPU should be give the the full term.
Author Response
Dear reviewer,
firstly, I would like to thank you for investing the time to read our article and for all your valuable comments. We have posted the responses under your comments (red)
The PDF format has many alarts like "presented in Error! Reference source not found" .
Unfortunately I didn't check the pdf exactly, only the word file. That is why the problem appeared. I can only apologise and thank you for your comment.
And there are many sentence like that on line 19 “Due to the difficulty of measuring the wear of bearings as well as windings of an electric machine, the dependence of bearing and windings on the ambient temperature by replacing the flight altitude by temperature. ” By the way, the abbreviations like APU and GPU should be give the the full term.
We gave our manuscript to professional English corrector and took under consideration all comments from reviewer.
Best regards,
on behalf of coauthors Justyna Tomaszewska
Round 2
Reviewer 1 Report
It's ok after answers and corrections
Author Response
Dear Reviewer,
Thank you very much for your comments and time. We appreciate its very much.
Best regards,
On behalf of coauthors Justyna Tomaszewska
Reviewer 3 Report
The article presents a method to predict the service life of aircraft commutator machines, based on a flight profile analysis. This research can be used in practice to plan maintenance work on the analyzed aircrafts. The topic is intresting. However, it is still hard to understand authour‘s meaning, although the manuscript has been improved in this version. For example, the sentence in abstract"Due to the difficulty of measuring the wear of bearings as well as windings of an electric machine, the dependence of bearing and windings on the ambient temperature by replacing the flight altitude by temperature. "
Besides, the format of the manuscript is not so adaptable. The authour should pay more attention.
Author Response
Dear Reviewer,
Thank you very much for your comments and time. We appreciate its very much. We gave our paper to additional English corrector, and we hope know is improved.
Best regards,
On behalf of coauthors Justyna Tomaszewska
