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Statistics are a way of assessing the quality of the data collected.
Standard Deviation (SD) is a mathematical calculation used on a set of data to
assess the amount of scatter or dispersion from the mean, or average. It is an
indication of accuracy. If all data points are exactly the same, the SD would be
equal to 0.
Wind Speed Measurements: The differences in wind speed were insignificant with a highest SD of 0.19 and a highest CV of 3.0%. The chart below is a summary of all wind speed measurements and statistical analysis.
Grand Mean of Wind Speed Measurements:
mVolt Measurements: The highest SD was 13.12 and CV was 7.08%. The chart below shows all of the mVolt statistics.
RPM Measurements: The highest SD was 20.98 and the highest CV was 6.86%. The chart below shows the statistics for the RPM measurements.
Summary of Statistical AnalysisThe coefficient of variation for all the data collected was acceptable (i.e. < 10%), with the exception of the mAmp results for one rotor variable at medium fan speed. The rotational speed of that particular rotor was relatively low and produced slightly more erratic results.
Overall, the data collected was accurate and precise.
My engineering objectives were met and the design of the laboratory scale model accomodated my experimental design. The results supported my hypothesis as follows.
I predicted that the number of rotors and their size, placement and
orientation on a single horizontal axis windmill would affect the amount of
torque and electrical energy produced. I predicted that the size of the DC motor
would affect the amount of electrical energy produced and that some rotor
variables would be unable to start and continuously turn the axle of larger DC
The results show that multiple rotors operated at lower wind speeds and had a higher conversion efficiency.