Voltage and current output performances of a low-power, low-speed induction generator

This paper addresses the voltage and current output performance of a low-power low-speed induction generator obtained as a modification result of single-phase capacitor motor. This application is prospective for microhydro power generation in rural regions, considering various prohibitive conditions in acquiring brand-new generators. Importing from far away or even from foreign countries sometimes is also difficult to do because of the low purchasing power of the local people, in addition to the lack of human resources with appropriate know-how to establish local machinery industry. Generating voltage up to its nominal value is not always easy to achieve even though rotation speed has reached or even exceeded its synchronous speed. Moreover, it also has to be excited using pre-charged capacitor. During start-up, any load should be disconnected in order not to discharge the capacitor. Once approaching its nominal output voltage value, load can be connected gradually. Increasing the rotation speed above its synchronous value will increase the resulted generator frequency, even though it is not linearly proportional to the rotation speed increase. The loading experiment is demonstrated using resistive load in the form of incandescent light bulbs. It is shown that the resulted generator voltage is of sinusoidal form, but certain distortion is found on the current waveform as a result of energy oscillation between the excitation capacitor and the generator winding inductance.