June 26, 2011
June 26, 2011
June 29, 2011
Electrical and Computer
22.276.1 - 22.276.9
Basic class materials and laboratory projects with DC motors in an introductory undergraduate ECE class for non-majorsMost electrical and computer engineering departments in the United States and abroad typicallyoffer a fundamental one or two-semester course in ECE for non-major students. Sometimes, thiscourse is offered to both majors and non-majors. In general, it is a very difficult task to teachcomplex electrical engineering concepts, including circuit theory, semiconductor fundamentalsand digital fundamentals in one course. Therefore, the intro class for non-majors (or for bothmajors and non-majors) is frequently devoted to circuit (and digital) fundamentals only. Thisscenario creates a visible dissatisfaction, especially among ME and CE majors, who wish to beexposed to power electronics - motors, even in their first ECE class. The same trend is observedfor ECE majors when both classes are combined together. The exposure to power electronics isthus not only beneficial for the intro class, but it may also stimulate further long-term interest inECE and Robotics. On the other hand, the systematic study of motor fundamentals including ACmotors in the intro class may not be possible as it would require a significant extension of thealready tight syllabus. What could be done to resolve this dilemma?This paper reports on our pedagogic approach of introducing the motor-related materials into theclass syllabus (3-4 lectures) and into one or two class laboratories in an engaging yet technicallycorrect way that is particularly appealing to non-major students. The supporting class materialshave the following features: 1. Only an introductory analysis of DC motors and DC generators operating in steady state is given, starting with the Lorentz force concept and linear motors. 2. Motor DC resistance, torque constant, and voltage constant are then introduced and studied. 3. Finding motor constants from the datasheet is suggested next. 4. Torque-speed curves using four motor measurables: no load , I no load , T stall , and I stall are studied afterwards. 5. Finally, the analysis leads to an example - a selection of a DC motor for a particular application including both steady-state operation and acceleration.The supporting laboratory syllabus has the following features: 1. In the first laboratory, a motor (a 12V surplus Mabuchi model for ~$5) is introduced as a load device. Students measure R M , I no load , and I stall . 2. In the following (or the same) laboratory, students connect the motor to a half bridge and to the full bridge and observe four different motor states: (i) forward mode; (ii) reverse mode; (iii) free run to a stop and; (iv) brake. The PWM is optional.We shall describe our experience with this scenario in an introductory course offered during Fall2010/Spring 2011 (about 250 students total), and the corresponding assessment results. Thecurrent assessment strategy and its follow-up modification (including critical alumni surveybased on the weighted response to the motor subject) will be described.
Makarov, S. N., & Ludwig, R., & Win, K. M. (2011, June), Basic Class Materials and Laboratory Projects with DC Motors in an Introductory Undergraduate ECE Class for Non-Majors Paper presented at 2011 ASEE Annual Conference & Exposition, Vancouver, BC. 10.18260/1-2--17557
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