Maximizing Motor Efficiency
In activity 1.2.5 you learned how to calculate the efficiency of the VEX motor when used to lift a weight. In this activity you will modify the conditions to optimize the motor efficiency. You might, for instance, lift more or less weight, or change to voltage, or change the gear ratio of the system.
- Define the Problem—review these rules and write a synopsis in your engineer's notebook. Research the topic using available resources.
- Generate Concepts—brainstorm ideas. Sketch possible solutions. Decide on a solution to develop further.
- Analyze the data from 1.2.5 to see which was the best design and the best voltage for maximum efficiency.
- Run your device with no load at the optimum voltage and record the current.
- Run your device at the optimum voltage while stalling the motor by holding the string and record the current.
- Consider how you could increase or decrease the gear ratio to the motor.
- Consider how you could reduce friction in the system.
- Develop a Solution—sketch the final design in your engineer's notebook.
- Construct and Test a Prototype
Evaluate the Solution—compare your performance to other teams in the class. Decide on ways to improve your device. Modify and retest.
Present the Solution—Document all six steps in the design process in your engineers notebook and provide an oral report to the whole class.
- Start with the device that you built for 1.2.5.
- Modify the device to increase efficiency.
- Conduct a series of test runs at varying voltage and load.
- Use the data sheet to calculate the input and output power for each test and the efficiency of your design.
- Enter your most efficient run on the leader board.
- Up to 10 points for having the highest efficieny in the class.
- Up to 10 points for documenting all of the steps in the design process in your engineers notebook. Evaluation will use the Design Process Rubric.
- Up to 10 points for the Oral Report. Evaluation will use the Oral Report Rubric.
- This is an activity for teams of 4 or 3 students. Your partners are the same as for 1.2.5.
- Each device is limited to the parts in the VEX kit and 1/6 of any one type of piece.
- Weigh the load in Newtons prior to lifting it. Only parts in the kit can be used for weight.
- Building, testing, modifying, retesting, and the oral reports will not exceed two class periods.
- Voltage is limited to that on the provided power supply.
Last updated on 23 October 2017