Design and Testing of a Open Source Permanent Magnet Generator for Pico-Hydro Systems

The study focuses on the design of an axial flux permanent magnet generator meant for low power electricity generation up to 100Watts. The design of the permanent magnet generator is made with open-source technology concept. This entails that the mechanical design is made in such a way that majority of materials and processes are readily available where the machine will be used, in this case in the rural areas where renewable source of energies are available such as wind and hydro. A prototype permanent magnet generator was made following the processes intended as an open-source technology. This entails some compromise in the performance of the generator as small tolerance cannot be achieved with simple manufacturing processes. The permanent magnet generator is then tested in a custom-made DC-motor driven dynamometer that was able to measure the torque input to the generator. Electrical load was applied to the generator through a simple rectifier-capacitor circuit and current and voltage output was measured. The result shown a maximum efficiency of 72% at a rotational speed of 955 rpm. The study proved that even for a simple permanent magnet generator design using modest tools and processes for manufacturing is possible. With optimization in the design, higher efficiency can be achieved and still maintaining simple manufacturing processes.