20-10-2012, 05:47 PM
An Energy Conversion Laboratory Using Industrial-Grade Equipment
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Abstract—
Laboratory experiences are an important component of the education of engineering students. Rotating machinery laboratories assist with the visualization of the three dimensional and rotating equipment. Contemporary use of rotating machines in industry often includes adjustable speed drives and digital controllers. Additionally, instrumentation is used to feedback electrical
and mechanical variables to the drives and controls. Using an equipment grant from an industrial automation manufacturer, cost-effective laboratory workstations have been developed. Industrial- grade equipment is not designed for student experimentation but was adapted for this use. The workstations described in this paper incorporate modern power electronic-based drives and motors, electrical and mechanical sensors, and a computer-based control system with data acquisition. The advantages of these workstations include cost-effectiveness and the use of actual industrial devices that students might encounter in industry. Additionally, the workstations can be accessed by remote users, enabling off-campus students to also perform experiments on the workstations. The paper includes details of the workstation and its components, the data acquisition and control system, and sample experimental results. Index Terms—Ac motor drives, ac motors, dc motor drives, dc motors, electric machines, energy conversion, engineering education, laboratories, workstations.
INTRODUCTION
IN the past, the laboratory was an integral part of an energy conversion class. Electric machines are particularly difficult for some students to visualize and a laboratory experience can help to reinforce the abstract concepts learned in a lecture class.
As university curricula become increasingly pressed for time and laboratory space becomes a premium, many energy conversion laboratories have been eliminated. Efforts are on-going at many universities to revitalize power engineering curricula and laboratories University electric machinery laboratories often contain old equipment. While these machines may be perfectly functional, students often perceive the laboratory as dirty, outdated, and uninviting Student interest can be improved by providing a laboratory with modern equipment where students can see relevance to what they will likely encounter in the workplace. Manuscript received November 28, 2007
OVERVIEW OF THE CLASSES
At Clemson University, two undergraduate classes and two graduate classes are directly related to electric machines, power electronics and adjustable speed drives. Additionally, a service course taught for non-electrical engineers contains significant content on electric machinery.
ENERGY CONVERSION LABORATORY
An energy conversion laboratory has been developed to support the courses listed in Section II above. This laboratory consists of six identical workstations, each equipped with electric machines, adjustable speed drives, computers and data acquisition, oscilloscopes and printers. These workstations were designed primarily for use by students located physically in the laboratory, but have the capability of being accessible by off campus by students using remote access and the internet. A unique aspect of these workstations is that they consist almost entirely of industrial components, allowing students to interact with devices they may encounter in industry. The implementation of the workstations with these devices, which were not designed for use in a teaching laboratory, is described in the paragraphs that follow.
Workstation Details
a photograph of the workstation, with the drives mounted on the backplane and the motors, clutch, torque sensor and tachometer mounted at the bottom. The computer and printer are located just beneath the countertop, and an LCD monitor on a pivoting arm is mounted to the backplane. Much of the wiring has been placed behind transparent polycarbonate shields so that local students can see how the components are interconnected. Safety sockets have been used so that students can connect to these wires with modern recessed “banana” jacks
to measure voltages without the risk of contacting exposed conductors.