FULLY ADJUSTABLE THREE-PHASE SYNCHRONOUS MACHINE- LABORATORY TEACHING EQUIPMENT FOR STUDENTS

Laboratory and practical classes coupled with theoretical work play a major role in the field of engineering education. This paper presents a fully adjustable three-phase synchronous generator developed in the electrical department of Tshwane University of technology South Africa. This experimental module consist of a single phase machine with variable frequency mechanically coupled to drive three-single phase alternators arranged geometrically to obtain a phase shift of 120 degree electrical phase shift for each phase. This equipment due to the flexibility of the coupling can be adjusted to a balanced or unbalanced three-phase supply via its variable phase’s amplitude, phase angle and alternator frequency. With these features, topics in electrical machines studied in textbooks such as balanced system, unbalance system, stability, synchronization, power import and export, effects of excitation etc. can easily be performed by students in the laboratory. Following the introduction of this equipment in the laboratory, several number of students have benefited significantly. Student attitude improved greatly, their understanding concerning unbalance system and related phenomenon grew significantly. Moreover the average mark and pass rates in courses like electrical engineering II, III and machines II and III increased tremendously. Presented in this paper are the architecture of the machine, laboratory tests and result.