Detection of Lubrication State in a Field Operational Wind Turbine Gearbox Bearing Using Ultrasonic Reflectometry

Round 1

Reviewer 1 Report

I have reviewed your very interesting paper on this field operational wind turbine gear box bearing with ultrasonic reflectometry. I do not have many questions or concerns regarding your nice work, although it would be better to put sensors on both CRB and TRB in the filed test, that would show even more interesting comparison between this 2 type of bearings. I believe there should be field warranty report of which bearing has higher failure rate, and the field test may be able to show the connection between insufficient lubrication and failure.

Do you have a cost estimation of such in-field sensor-monitoring set? a rough range of cost would be great to show the potential of installing such device on every wind turbine gearbox.

Author Response

Please see the word document attached. Thanks.

Author Response File: Author Response.docx

Reviewer 2 Report

Review Comments:

1. The authors are suggested to explain the novelty of the paper.

2. The authors are suggested to add more references related to the paper.

3. A schematic diagram or physical map of the test rig should be added.

4. A diagram of the specimen should be given.

5. What are the probable error sources of the experimental data? Error analysis should be added.

6. For the conclusions, it is too long. Several brief points of conclusions are enough.

The authors are suggested to rewrite the conclusions.

Major revision.

Author Response

Please see word document attached. Thanks.

Author Response File: Author Response.docx

Round 2

Reviewer 2 Report

Review Comments: From the whole prospect of view, the authors have revised the paper point by point. Now it is suitable for publication for the journal. However, a richer literature review, including the lubrication regimes of the bearing is needed in the paper. For example, [1]. Experimental research on water-lubricated marine stern tube bearings in conditions of improper lubrication and cooling causing rapid bush wear [J]. Tribology International, 2016, 95: 449-455. [2]. Experimental research on the interface lubrication regimes transition of water lubricated bearing[J]. Mechanical Systems and Signal Processing, 2020, 136: 106522. [3]. From full-film lubrication to boundary regime in transient kinematics [J]. Tribology Letter, 2015, 59(1): 1-10

Author Response

Thank you for the review, please see attached.

Author Response File: Author Response.docx