Aristidis Zachas and Long Wu with advisers T. G. Habetler, D. M. Divan, and R.G. Harley, Georgia Institute of Technology

Figure 7 Conceptual design for hand-crank generator.

Figure 7 Conceptual design for hand-crank generator.

The concept of a portable hand generator has been successfully evaluated, and a final design has been developed. From the research conducted, it is noted that the output power available from a person is in the region of 30-70 W for a hand-crank application. With this in mind, an axial flux generator was designed that could output 50 W if a rotational speed of 3000 rpm could be maintained. Through the use of two belt stages, a step-up ratio of 1:50 has been designed so that the user of the generator would need to rotate the hand crank at 60 rpm. The use of an axial flux machine allows for a good power density and thus improves the performance and size of the system. The magnets on the rotor of the axial flux machine have been skewed to reduce the cogging torque of the generator. The mechanical design would require further review, but a concept has been provided that allows for a rigid frame to support the system. A complete system has been designed as a secondary power source that could improve the quality of living for isolated and off-grid communities.