The Design of the Outer-Rotor Brushless DC Motor and an Investigation of Motor Axial-Length-to-Pole-Pitch Ratio

Round 1

Reviewer 1 Report

In this study, the effects of axial length to pole pitch ratio change on efficiency, magnetic flux density distribution, torque, torque/weight motor volume of outer rotor (Hub) brushless direct current motors (BLDC) have been investigated. Initially, the axial length to pole pitch ratio of the hub BLDC motor is taken at 0.75. According to this ratio, the dimensions of the rotor outer diameter, rotor inner diameter, stator outer diameter, stator inner diameter, slot height, motor axial length, and magnet thickness are determined optimally. Then, the axial length to pole pitch ratio is taken into account as 1, 1.50, 2, and 3 respectively. The effects of motor axial length pole pitch ratio change on efficiency, torque, speed, torque/volume, torque/weight, and cogging torque were performed in the simulation environment. According to the motor axial length pole pitch ratio, the torque value in the final state is 28.65 % higher than the torque value in the initial state. In the last part, the motor axial length and the stator outer diameter are defined as variables in the genetic algorithm procedure and optimized. The number of poles and the number of slots are fixed parameters. Simulation studies have been carried out using the finite element method via ANSYS/Maxwell software. The aim of the analysis should be evidenced in the abstract and introduction sections. The methodology should be further explained for replication. Finally, the manuscript should be English proofread because some sentences are not clear.

Author Response

The corrections you requested for the article have been made. Thank you for your comments.

Kind regards.

Author Response File: Author Response.docx

Reviewer 2 Report

The title of this paper is “Design of Outer Rotor Brushless DC Motor and Investigation of Motor Axial Length to Pole Pitch Ratio”. Brushless DC motor has the advantages of high efficiency, high power density, good torque, easy control and low maintenance cost. Therefore, brushless DC motor is widely used in industrial automation. In this study, the motor size has been determined by considering the motor size boundary conditions, and the influence of axial length and pole distance ratio of outer rotor (hub) brushless DC motor (BLDC) on efficiency, magnetic flux density distribution and magnetic flux density distribution has been studied. However, the following points should be noted:

1. Too many keywords.

2. Mentioned in the article“…the optimum pole arc to pole-pitch ratio, and the efficiency maximization, are some of the operational key elements…”, this paper focuses on the axial length and polar distance ratio, and suggests that the significance of the best polar arc and polar distance ratio can be expounded in detail to supplement the background narration of the conclusion.

3. The layout of pictures and tables in this paper is suggested to be optimized, and some pictures are not clear enough.

4. Unify the abbreviation of genetic algorithm.

5. In the article, the symbol of quantity should be printed in italics.

Author Response

The corrections you requested for the article have been made. Thank you for your comments. 

Kind regards.

Author Response File: Author Response.docx