Graded Unit 2 Stage 3

Dylan Fitzsimmons30050607

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E3HNDMECEN

DV1235

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ContentsTesting page3

Results page4

Potential Faults page4-- Electrics

-- Build Quality -- Calculations page5

-- Components

Potential Improvements page5-- Electrics

-- Build Quality page6

Schedule Review page6

Progress Reporting page6

Contingency Solution page7

Workshop Strengths page7

Workshop Weaknesses page7

Quality Control Measures page7

Health and Safety page8

Personal Contribution page8

Skills Developed page8

Reflections page8

Acknowledgements page9

Appendix page10

Photo Diary page11

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Testing (19/05/2016)Soon after the motor was secured into position, a testing procedure was carried out on the turbine to check for any irregularities or safety concerns (appendix). Once this was complete, the product was carried through to workshop R.00.075 by all 4 members of the team (a member at each corner, complying with the current lifting procedure as to avoid injury); where the turbine would be housed throughout the performance tests.

To prepare the turbine for performance testing, the wires protruding the motor first had to be connected to the junction box containing the light bulb. This simple task was done using a flat screw driver, in which the neutral wire from the motor was connected to the opposing neutral wire in the junction box. Likewise, the live wires from each component were connected using the same method. Finally, a voltmeter was connected parallel to the junction box, monitoring the voltage output of the turbine. (Picture1, 2)

Throughout this process, each member was wearing the mandatory PPE: overalls, steel toe cap boots, and safety goggles. Additional safety precautions were taken as the powerful fan and the swirling motion of the aluminium blades provided a potential hazard; each member positioned themselves away from any harm the fan or turbine could present. (Picture3)

Participant RoleJohn Robertson Fan Operator

Kieran Johnstone Wind Speed MeasurementDylan Fitzsimmons Video Recording

Chris Walker Voltmeter ReadingCharles Thomson Taking Results

Results6 tests were undergone by the team; with a variation in wind speed and distance:

Test Voltage (v) Wind speed (m /s ) Distance From Fan (m)1 N/A 5 12 2.26 4.7 13 0 3.4 24 0.36 6.4 35 0.224 6.6 36 0.4 6.7 3

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In correspondence with the results, the final product failed despite achieving the build specification; derived from the initial calculations. The closest the turbine came to meeting the performance specification was during the 2nd test (2.26V), as the wind speed reached 4.7 m /s at a distance of

1m. Short of 9.74V, the output was only 18.83% of the 12V target. To be able to understand why the product failed to achieve its target, a number of variables must be considered.

Potential Faults

ElectricsThe most prominent of those variables is the concern over the electrical side of the project. Judging by the evidence gathered by the test results, it is clear that the fluctuations in voltage output do not correlate with the change in wind speed. Test 1 (N/A) cannot be considered for this purpose as the junction box was not switched on, preventing the voltmeter from taking a reading. However, the 3 rd test (0v) gave no reading despite the conditions being the same as test 2; with the exception of the change in distance from the fan. Going by the results of 4 (0.36V), 5 (0.224V), and 6 (0.4V); distance was not the issue, which provides more evidence against the electrics. This would lead to the conclusion that during test 3, the voltmeter was not connected correctly to the junction box.

Concerns were also raised about the junction box, as the term used to describe the piece of equipment was ‘flimsy’. The verdict by visual inspection and physical manipulation was that the component may have some underlying defect, although this cannot be proven with evidence as it was only an observation. The reason for this assumption is the unexplained peak during test 2, despite test 6 providing the greatest wind speed.

Build QualityAlthough when the turbine’s shaft was initially installed it was perfectly straight, the process of removing sections of the base and shaft supports during the connection of the motor had resulted in a crucial defect. As the base was reassembled, the shaft supports were skewed to one side, having a negative impact as the blade rotated on its axis. The effects of this are unknown, although by speculation it can be assumed that the uneven spin may have created a pulsating effect: preventing higher speeds as the turbine accelerated and decelerated on opposing sides.

Due to a mistake in measurement when cutting the nylon, the holes did not align with the blades; resulting in blade support 4 pulling the aluminium up at an angle. This may have led to boundary layer separation of the wind flow; potentially creating form drag.

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2.5Figure 1 Test Results

Figure 1 Test ResultsTest

Volta

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Another concern was the air gaps between the aluminium and the blade covers. The idea was that the covers would prevent air passing over the blades; forcing it into and through the turbine. However, the loose covers did not seal the air completely – which could lead to the presumption that the design idea on a whole was almost oxymoronic. It is not wise to assume the blade covers are a major aspect in the turbines performance failure, although it may have been one of many issues that are responsible.

CalculationsDuring the initial calculations, using a power coefficient value of 0.25 and the blade area of 0.565m, the intended power output was expected to achieve 26.1W. However, a more realistic value would have been lower since the team was operating with a relatively low skillset, and if the power coefficient was lower: the diameter of the blade should have been greater. The increase in wind capture area may have resulted in a higher RPM value.

ComponentsWithout evidence it is not wise to conclude that the motor or bearings may, or may not, be at fault. However, it would also be wise not to rule out the idea.

Potential Improvements

ElectricsSince the argument of failure is mostly based upon the electrical side of the project, considerable improvements would need to be made if a second attempt was to succeed. The first addition would be that of an inverter, the device that changed the DC current produced by the motor into AC; which is necessary for lighting a light bulb. Secondly, a step-up transformer would be required to enhance the voltage output from test 1 (2.26V) to the 12V that was required. The final change would come from the installation of a voltage regulator, placed between the junction box and the voltmeter: stopping the fluctuation in readings. (Figure 1)

Figure 1

Build QualityThe Savonius produces its best power coefficient value when the tip speed ratio is just under 1, that means that the tip of the blades are spinning slightly less than the free flow of air that it captures. This is due to the Savonius being a drag type wind turbine; it spins because there is less drag in the open blade than in the closed blade. In addition to the wind force, the pressure difference is also responsible for the rotation of the blades. As a consequence of its design, the Savonius best operates

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in low speed winds; as the drag forces increase with the wind speed, and the RPM will plateau. A potential solution to this would be the introduction of a more aerodynamic shape to the rear of the blades, one which displaced the wind in a more efficient way – reducing drag.

Schedule ReviewAt the beginning of the process, the SKYE Ltd team were well organised for the construction process that was about to begin (23/03/2016). All vital documents that were required were complete: method of manufacture, engineering drawings for each component, risk assessments and planning Gantt charts. The group did not experience any problems until the 5th week, when the motor and bearings did not arrive. The bearings were delayed until the 6th week, although this did not raise too much concern over whether the issue would threaten the chances of success; as the hard work and efficient preplanning of the previous weeks had put us in front of schedule. However, when the motor did arrive, serious concerns were expressed within the group, as it was considerably smaller than expected; a challenging task lay ahead to connect the small component to the shaft. As the initial coupling design to attach the motor was no longer a realistic method of attachment, there was a feeling that the failure to foresee such an event could be detrimental to the final assembly of the product. Throughout days between the 11-13/05, multiple theories were conceived; a range of ideas on how to solve the problem. Ultimately, all failed – and the team were reliant on another group as part of our contingency plan.

If the process was undertaken a second time, improvements in the schedule would have to be made. The most important of which would be the order of components, such as the bearings and the motor, weeks in advance – in case any issues presented themselves, the team would have more time to deal with them in a calm and logical manner.

Progress ReportingAlthough only one client meeting took place during stage 2 (10/03/2016), team meetings were held consistently throughout the process. The meetings, which on average lasted an hour, helped the group establish its current position in relation to the schedule. The meetings were also responsible for group decisions that would be made in advance of the workshop days. Without regular meetings, the team would have struggled to come up with a solid plan to counter the delays that came with the motor and bearings.

In addition to client and team meetings, the group kept in constant contact through the use of Facebook messenger; enabling us to build up a healthy working relationship that would improve output and productivity. The social media site was also used as a platform for unofficial meetings, as any member could be accessed at any time, such as weekends.

Progress reporting was also completed on a personal level, with the use of the log book. The log book allowed each member to leave a trail of events that could be traced back if presented with a problem, used as a template for a similar task or when improving the product.

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Contingency SolutionA contingency plan was set in place to prevent the group from running out of time throughout various points in the project. This included time to arrange replacements, account for delays and absences (to which there were none). As the product progressed through its stages of construction, there were delays which were able to be contained because the plan was in place. However, due to a congregation of unexpected negative impacts (timetable issues and motor failure); the time that was put aside for emergencies was almost gone.

At the end of week 6 on the 3rd workshop day, the team was struck with the failure of a major component. As the team had been attending extra days, there was a short window of time (5 days) to which the motor would need to be replaced if the product was to be completed. Thankfully, another group had just finished using its motor for testing, which was kindly loaned to SKYE Ltd for the duration of testing.

Workshop Strengths High work ethic Communication Initial planning Problem solving Creativity Ingenuity Working under pressure Attention to detail Documenting work

Workshop Weaknesses Lack of knowledge in relation to electrics Planning could have been improved in some areas

Quality Control MeasuresA high standard of quality was maintained throughout the project, which ranged from the upkeep of documents (engineering drawings), to staying motivated and confident; maximising productivity. Measurements were regularly inspected (checked twice before cutting), and the completion of a verification strategy to sign off the turbine for testing.

Health and Safety ComplianceVarious health and safety concerns were raised: handling the aluminium sheets, overcrowding in the workplace, minimal supervision (1 lecturer), and noise levels. However, despite these concerns there were no accidents. Every member of SKYE Ltd new the health and safety regulations of the college, and conducted themselves in a professional and cautious manner.

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Personal ContributionMy personal contribution in terms documentation was the completion of risk assessments and the writing of a design verification strategy.

Throughout the manufacturing process, each member of the team brought a different set of personal qualities that helped with each task. I felt like my personal qualities in particular were used well within the group, such as my creativity; which helped when designing and building the motor vice and blade covers marking tool. As well as being creative, every task that I was a part of was undergone with a high standard of attention to detail; so that every measurement and cut was precise. As I have past experience with metal and wood work, I was able to help out members of the group with tasks when they struggled, and even members of other groups. Some students feel embarrassed to ask for help, which is why I was able to help indiscriminately by remaining observant of what was going on around me at all times. Building on this, I was able to communicate well with some individuals, even members of other groups. However, the most prominent contribution I was able to give was my work ethic; working from the moment I got in class until the moment I left, working on through optional breaks.

Skills DevelopedI became more competent with the tools in the workshop throughout the construction process, further developing my experience with pieces of equipment such as: the milling machine, pillar drill, portable hand drill, and the jigsaw. I also learned how to better conduct myself around the workshop, shaking off bad habits. The experience gave me the opportunity to put the theoretical knowledge I previously learned within the college into practice in a simulated working environment.

ReflectionsFrom beginning to end, the process was very stressful. I fully enjoyed the workshop and the feeling of satisfaction from achieving something of worth, and I am proud of what we as a team have managed to bring together. The group was able to achieve the vast majority of the project independently – through trial and error mostly. In its entirety, the process took up a considerable amount of time which I was more than happy to commit to.

The experience expanded my knowledge in areas that theoretical work alone cannot teach, to which I am grateful. I fully believe that if I were to undergo the project again, it would exceed the performance specification.

AppendixPre-test Checklist

Component Task Description DateLarge fan Check power switch Turn on and off

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Large fan Clear area for test Move objects obstructing test out of the way, alert other lectures and colleagues in the area to stay clear.

Large fan Move fan into required position and secure

Locking the brakes on the fan frame.

Large fan Fan ready for test.Component Task Description DateSavonius Secure turbine into

testing positionUsing all members of the team and following all regulations in safe lifting pace in required position.

Savonius Tighten all nuts and bolts Using a 14mm spanner, go around turbine and begin to tighten all nuts and bolts

Savonius Grub nut check Ensure grub nut it tighten so connection with the shaft it made.

Savonius Check turbine rotates without any obstructions

Spin the turbine by hand and see if any obstructions stop it

Savonius Motor check Check the motor is connected correctly and tight

Savonius Wind gauge Wind gauge used to test wind speed and write recordings

Savonius Testing sheet to record results

Member of the team has a testing sheet and one recording

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Photo Diary

Picture 1 Picture 2

Picture 3

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