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 theopportunity to reduced costs and increased system efficiency. This type of generator couldbe the best alternative for rural population whom are not connected to the national grid. Toimprove the design and efficiency of locally fabricated generators, it is imperative tocharacterize both their mechanical and electrical parameters. This paper presents theanalysis of power efficiency of the synchronous permanent AC generator locally fabricatedin Tanzania. In this case, load resistance and rotational speed are characterized usingdesigned experiment. The output current and voltage of the generator were recordedsimultaneously in each step change of load resistance and rotational speed. The outputpower and efficiency were then determined analytically. The results show that there is alinear relationship between voltage and rotational speed of the generator with and withoutload resistance. The results further indicated that out power is not linearly related torotational speed. The generator €¢s power efficiency was found to be about 55% against boththe output voltage and rotational speed.