In this assignment, you will apply the concept of power generation to design and construct a windmill that produces a the maximum amount of power. Remember what you learned in your technology education class—an electric motor can be connected to a battery to supply mechanical energy. During your study of electric motors, you discovered that if mechanical energy were supplied to spin the motor, you could generate a small amount of electricity.
You and your friends want to build a clubhouse in a secluded spot that does not have any electricity. Therefore, your class has decided to build a windmill to provide electricity for lighting. Since everyone has a different idea of what the windmill should look like, each person in the class will design and construct a propeller to go on the wind generator.
Achievement—To meet the requirements of the challenge, you will:
- Design and construct a propeller for a wind generator to obtain the maximum power output while powering electric lights.
- Demonstrate the performance of the propeller in a series of test runs. For each test run:
Make changes to the device to maximize the power output. Changes that can be made include the pitch of the blades, number of blades, diameter (or blade length), shape of the blades. Entirely new propellers can be designed and manufactured using the same or different construction materials and methods.
Retest after each change and compare the power output.
Document in your Engineering Design Journal how you solved this problem, summarizing your design and describing the factors that determined its performance.
- Measure the voltage at the generator.
- Measure the current to the load.
- Calculate the power being delivered. The power output of the
generator is the output voltage multiplied by the output current, or:
P = I V
Where: P= output power, measured in watts
I= current flow to load, measured in amps
V= Voltage at generator, measured in volts
- Vary the load to maximize the power output.
- Record the voltage, current, and power for the optimum condition.
- Students will design build and test their device individually.
- The maximum diameter of the propeller may not exceed 6 inches.
- The propeller should be designed to mount on the existing shaft.
Criteria—The evaluation of the task will be based on the following.
Product—Propeller (20 points)
- Meets overall design requirements as built.
- Well constructed to close tolerances.
- Structurally sound.
- Well balanced.
Performance (20 points)—The performance of the product will be based on the amount of power delivered compared to the rated power of the generator.
Engineering Design Journal (10 points)
Submit your Engineering Design Journal for review at the end of this activity. Make sure you have documented all of your efforts, including the results of each propeller tested.The evaluation will be based on the following:
- Every page numbered sequentially (outside top). Table of Contents complete.
- Efficient use of pages, no large blank areas.
- Inserted items permanently attached.
- Designer signed and dated each page.
- Each entry dated.
- Witness signature and date when appropriate.
- All figures and calculations labeled. Annotated sketches included.
- Design Process Documented. Clearly explains how designs were supposed to work.
- Results of test provided. Problems encountered and ideas to fix them chronicled.
- Information given in the entries proportional to the amount of time spent on project.
Last updated on 2 March 2019