2026 ASEE Annual Conference & Exposition

This paper represents an educational experiment designed to illustrate the principle of self-excitation in induction machines and to provide a full range of load for a motor-generator set consisting of a Type III Doubly-Fed Induction Generator (DFIG) and Squirrel Cage induction motor. In the setup, a three-phase induction motor which is here referred as Gold machine, was driven to become self-excited through a wye-connected capacitor bank with 66.7 µF per phase providing the reactive power required for magnetization. Without an external excitation source, the machine-capacitor system was able to steadily function and build up voltage due to the generated reactive current. The machine was able to generate sufficient reactive power and also to generate full rated real power near its rated voltage. Through this configuration, students can directly observe how enduring magnetism and capacitor configuration run an Induction Machine by self excitation without using any extra power supply. The experiment provides a clear visualization of how reactive power supports self-excitation, and is helpful for students to have hands on experience for the lab purpose. Instructors can use this configuration with a load bank to effectively demonstrate the operations of induction generators in the classroom and laboratory, which makes it a useful teaching tool for electrical machine and renewable energy courses. Calibration of the Gold machine, capacitors, and load bank to serve as a valuable replacement for the typical DC Machine component of a motor-generator set will be explained in the paper.