St. Louis, Missouri
June 18, 2000
June 18, 2000
June 21, 2000
5.424.1 - 5.424.12
Learning About Engineering Design Through Product Dissection
Steven Mickelson, Carl Bern, Richard Freeman Iowa State University
The electromechanical watt-hour meter is a familiar sight on utility posts and buildings everywhere. Millions of these meters register electrical energy use for the purpose of revenue billing by electric power suppliers. Watt-hour meters are excellent engineered products for learning about the engineering design process and the engineering disciplines through the use of reverse engineering or product dissection. At Iowa State University, we are using these meters to provide an experiential, hands-on mechatronics laboratory for junior high, high school, and freshmen engineering students. This paper describes the process used in the mechantronic laboratory and many opportunities for using these engineering masterpieces.
Electromechanical watt-hour meters have been under continuous development since 1888, when Oliver Shallenberger and Thomas Duncan built a working model1. As a result of this development, modern meters, such as the three-wire single-phase model shown in Figure 1, are masterpieces of engineering design. These meters: • Operate with a registration error of less than 0.5 % over a load range of 0.5 to 100 percent of maximum load. • Maintain high reliability while withstanding direct sunlight, arctic cold, tampering, and blows from irate customers. • Have a working life of up to 50 years. • Can be purchased new for under $30.
As watt-hour meters become defective or obsolete, they are replaced. In Iowa, with over 1.4 million meters in use, two to three percent (28,000 to 42,000 watt-hour meters) are replaced each year. Most of these meters are discarded and end up in landfills. Some power suppliers will supply discarded meters for educational use.
The electromechanical watt-hour meter is ideal for reverse engineering exercises or product dissection for the following reasons: • Meters are readily available at little or no cost. • Meters can be safely disassembled with simple tools. • Components can be easily identified during disassembly, and can be utilized in learning the meter’s principles of operation • Design, development, assembly, sales, and utilization of watt-hour meters involves virtually every engineering discipline. • A wide variety of materials can be identified among the meter parts.
Freeman, R. W., & Bern, C. J., & Mickelson, S. (2000, June), Learning About Engineering Design Through Product Dissection Paper presented at 2000 Annual Conference, St. Louis, Missouri. https://peer.asee.org/8534
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