ANALYSIS OF POWER EFFICIENCY OF A DIRECT-DRIVEN LOCALLY FABRICATED PERMANENT MAGNET AC GENERATOR FOR SMALL-SCALE WIND POWER APPLICATIONS IN TANZANIA

Abstract

The use of direct-driven permanent magnet alternating current (AC) generators offers the
opportunity to reduced costs and increased system efficiency. This type of generator could
be the best alternative for rural population whom are not connected to the national grid. To
improve the design and efficiency of locally fabricated generators, it is imperative to
characterize both their mechanical and electrical parameters. This paper presents the
analysis of power efficiency of the synchronous permanent AC generator locally fabricated
in Tanzania. In this case, load resistance and rotational speed are characterized using
designed experiment. The output current and voltage of the generator were recorded
simultaneously in each step change of load resistance and rotational speed. The output
power and efficiency were then determined analytically. The results show that there is a
linear relationship between voltage and rotational speed of the generator with and without
load resistance. The results further indicated that out power is not linearly related to
rotational speed. The generator•s power efficiency was found to be about 55% against both
the output voltage and rotational speed.