An Electromagnetic Circuit Design to Improve a Multi-Stage Coil-Gun’s Energy Conversion Efficiency
Round 1
Reviewer 1 Report
The manuscript presents experimental work on a multi-stage electromagnetic accelerator gun. The work was performed based on “generic principles” and few 2D simulation were performed along with the experimental work. However, the authors did not present any calculation behind the presented experimental or simulation results, did not present any ‘effective’ criteria on which their experimental work “optimizations” and experimental setup design were performed. In my opinion the manuscript should be completely re-written in order help the reader follow the presented work, and extensive English language corrections should also be needed. Some punctual comments are also mentioned below:
Abstract:
“the improvement was realized” … English !
“In effect, designing the coil using 1.3 mm diameter copper wires, among the coils using copper wires of various diameters, to increase the number of turns and reduce the capacitance improved the energy efficiency while enhancing the acceleration performance.” English !!!”Finally, the measured and simulated velocities of each stage in the multi-stage coil gun were analyzed/compared, and accordingly, an efficient design method for multi-stage coil gun systems were arrived at.” English !
Introduction
“and the design method, based on the design method” English !
Coil Gun
“Before designing and experimenting with any coil gun circuit, the launcher that would
be used in the coil gun was decided” English !
… and many other problems on English.
Fig. 4 – There are no (generic at least !) equation or models of any kind or specified approximation or anything to support obtained curves presented there. The accuracy of the results could not be evaluated in any way by the reader.
Equations (2) and (3) are actually definitions and not equations !
“So, if the goal is to derive maximum launcher velocity from a limited number of stages in a multi-stage coil gun, it is recommended to fabricate a solenoid coil using a large diameter copper wire and construct an RLC function suitable for the circuit using a high capacity capacitor.” The statement is actually rather a comment, because it should be supported by some experimental graph/equation/simulation and not just definitions.
Fig. 7 and Fig. 8 are giving the reader an idea about how the authors are doing their experiments but are far from helping them understanding the setup scheme behind the presented experimental results. Thus, setup schemes MUST be added for clarifying system functionality aspects.
“Here, an SCR thyristor was used for the discharge circuit, and the discharge control signals were outputted using Arduino, a commercial development platform. However, since the signals outputted from the Arduino were insufficient to operate the SCR, a method of amplifying the output signals with a MOSFET device and an external power source was used.” This discussion should be based on numbers and on scheme, none of them included here. The comment is available also for the further presented remarks and discussions !
“The velocity of the launcher was measured using the velocity measuring equipment shown in Fig. 9.” The equipment should be described (model, producer and so on) and its main parameters presented.
“Discussion” section is actually the Conclusion sections
“The first method is designing the coil with a lower capacitance by using a small diameter copper wire” The authors presented some results on combined variations of capacity and number of coils and consequently the magnetic field and respectively force. In this way, the reader could not actually understand the ”exact” capacity influence as long as none of the presented experimental results or theoretical simulation does not refer to this parameter alone but only to combination of parameters.
“Therefore, a multi-stage coil gun should be designed to match the period of the RLC function using a high capacitance and by increasing the magnitude of the current supplied to the coil.” Actually the authors did not mention why and how did they chose the number of modules, how did they optimize each module and based on which criteria.
Author Response
A1) Grammatical errors in the paper were corrected and reviewed by English native speaker.
A2) The graph in Figure 4 is the result of a finite element analysis performed using ANSYS Maxwell. We also added a mathematical model of the coil gun which includes the RLC function’s equation. The projectile’s velocity in the coil gun circuit was difficult to calculate due to the complexity arising from the entanglement of many equations. Therefore, we derived the graph using a finite element analysis program. The coil gun model described later was used as the finite element analysis model. The relevant content was added to the paper.
A3) The equation was deleted to correct the relevant matter.
A4) The coil gun model was optimized with the design of the experiment method. We determined the single-stage coil gun’s optimization models based on the diameters of individual copper wires, and the design variable ranges were also added. We designed the coil gun systems according to the copper wire diameters based on the projectile used in this study. Results demonstrated that the highest velocity was derived from the coil gun system having a 1.7mm copper wire, but the capacitance of more than twice compared to the velocity increase was derived as the optimal value. Therefore, for the sake of energy conversion efficiency, we decided to configure the coil gun system using a 1.3mm diameter copper wire.
A5) A schematic diagram of the charge-discharge circuit wiring of the multi-stage coil gun used in the experiment was additionally presented.
A6) The operating voltage and current of the SCR used in the experiment were written, and the same was done for Arduino digital output current and voltage. Although the Arduino can operate four SCRs, we used this paper’s method because the output power was insufficient for operating all of the nine-stage coil gun’s SCRs.
A7) The manufacturer and model number of the velocity measuring equipment used in the experiment were added, and the measurement information was added as a table.
A8) The subtitle of the relevant section was corrected.
A9) The optimal values derived in this study based on the projectile used in the experiment were added to the conclusion. The purpose of the optimal design process was to design a coil gun system with an RLC function’s period that enables a suitable energy distribution for the projectile acceleration’s shape. Here, we presented the method to set the coil gun circuit’s RLC function. When the system was configured using a 1.3mm diameter copper, the solenoid coil’s resistance and inductance were higher than those of the one configured using a 1.7mm diameter copper wire. Therefore, we designed a coil gun system with a lower capacitance. However, there was almost no velocity difference compared to the capacitor’s capacitance because the solenoid coil’s number of turns and magnetic flux density were high.
Author Response File: 
Author Response.docx
Reviewer 2 Report
This is a quality report on "Coil gun via ELectromagnetic Circuit Design". A few technical and illustration issues need to be addressed before it is considered for publication.
1. It is recommended that the authors add "Symmetric schematic illustration" alongside with the digital image in Figure 7 to demo the fabrication procedures of nine-stage coil gun.
2. Similar, it'll be better if the authors could provide a clear schematic charge-discharge circuit to match the set-up as displayed in the digital image. This could help readers easily understand and duplicate the system fabrication.
3. Figure 10 and 11 can be merged into one Figure 10 (a) & (b).
Author Response
Q1. It is recommended that the authors add "Symmetric schematic illustration" alongside with the digital image in Figure 7 to demo the fabrication procedures of nine-stage coil gun.
A) A schematic diagram of the circuit wiring was added to help readers understand the coil gun system configuration.
Q2. Similar, it'll be better if the authors could provide a clear schematic charge-discharge circuit to match the set-up as displayed in the digital image. This could help readers easily understand and duplicate the system fabrication.
A) A schematic diagram of the charge-discharge circuit of the coil gun system was added to the body.
Q3. Figure 10 and 11 can be merged into one Figure 10 (a) & (b).
A) The two figures were merged, and the relevant content was corrected
Author Response File: Author Response.docx
Reviewer 3 Report
This paper designs analyze the electromagnetic circuit to improve energy
conversion efficiency and acceleration performance in a multi-stage coil-gun.
The manuscript is publishable for the journal, but it needs improvement.
My comments are as follows:
1. The abstract should be improved.
2. The conclusions should be added.
3. The literature reviews should be improved.
4. The grammar mistakes in the manuscript should be corrected.
Author Response
Q1. The abstract should be improved.
A) Grammatical errors in the abstract were corrected and reviewed by English native speaker.
Q2. The conclusions should be added.
A) Opinions were added to the optimal design process and conclusion sections.
Q3. The literature reviews should be improved.
A) The contents of the previous studies referred to when writing this paper were added to Introduction and reference items were added accordingly.
Q4. The grammar mistakes in the manuscript should be corrected.
A) Grammatical errors were corrected and reviewed by English native speaker throughout the paper
Author Response File: Author Response.docx
Round 2
Reviewer 1 Report
The manuscript was improved in terms of data available for the readers, but in terms of presentation there are still thinks that could be improved. Some of the graphs and tables could be presented together and should also presents comparative results of the predicted and measured data, as long as they are both available. English language could sill be improved in my opinion. More detailed comments are presented below:
English problems examples:
- “Notably, in this research, not only did we set the used copper wire’s as a design variable, but also the coil’s number of turns “ ???
- “Particularly, the improvement was realized by designing a solenoid coil and capacitance for projectile velocity enhancement in a multi-stage coil gun based on simulations and experiments” How about ‘achieved’ or ‘obtained’ or performed or … something else ?
- “Based on the analysis, we judged that it would be appropriate to configure the coil
gun system using a 1.3mm diameter copper wire.” - How about ‘considered’
Fig. 1, Fig. 2, Fig. 3, Fig. 5, Fig. 6 and Fig. 11 contains sets of identical (or almost identical) images
Fig. 4 contain 2 images with different numerical information with no comments on that !
Tab 3 and Tab 4 why they are not joined into a bigger table ?
Tab 6. How about introducing (for inter-comparison reasons) the simulation values of the measured parameters ? (E.G. Measured/Predicted … or something similar). Similar for Fig. 12 to compare the predicted and measured curves ?
Author Response
Q1) English problems examples:
- “Notably, in this research, not only did we set the used copper wire’s as a design variable, but also the coil’s number of turns “ ???
- A) Grammatical errors in the paper were corrected.
- “Particularly, the improvement was realized by designing a solenoid coil and capacitance for projectile velocity enhancement in a multi-stage coil gun based on simulations and experiments” How about ‘achieved’ or ‘obtained’ or performed or … something else ?
- A) I revised it to "Performed"
- “Based on the analysis, we judged that it would be appropriate to configure the coil
gun system using a 1.3mm diameter copper wire.” - How about ‘considered’
- A) I revised it to “Considered”
A1) Grammatical errors in the paper were corrected
Q2) Fig. 1, Fig. 2, Fig. 3, Fig. 5, Fig. 6 and Fig. 11 contains sets of identical (or almost identical) images
A2) The redundant images are deleted
Q3) Fig. 4 contain 2 images with different numerical information with no comments on that !
A3 ) The schematic illustration of the situation where the center of gravity of the projectile passes through the center of the solenoid coil at 3.8 ms. I thought it would not be necessary to understand the contents of the text, so I only expressed the graphics.
Q4) Tab 3 and Tab 4 why they are not joined into a bigger table ?
A4) The tables have been merged
Q5) Tab 6. How about introducing (for inter-comparison reasons) the simulation values of the measured parameters ? (E.G. Measured/Predicted … or something similar). Similar for Fig. 12 to compare the predicted and measured curves ?
A5 ) The error rate with the simulation value is displayed in table 6 (table 5 after correction), and the simulation value is also displayed in Figure 12.
Author Response File: Author Response.docx
