Appropriate technology

Abstract

The author reports about two engineers in Nepal who have been trying to reduce the costs of the micro-hydro-electric plants that they manufacture and install for remote villages. They have built 30 of the 600 micro-hydro sets installed in the last 10 years in Nepal (primarily used for grain milling), and they compete with eight other Nepali companies. Recently they started to use induction generators, with cheap Chinese industrial induction motors and fixed capacitors for the excitation. They were successful to a point with fixed village-lighting loads, but had been wrestling with the problem of voltage regulation with varying loads. They succeeded in the design of a simple and cheap electronic regulator that, while allowing some small frequency drift, will keep the voltage within ± 10% - acceptable in the circumstances. Rural areas in developing countries cannot hope to have their electricity externally supplied; they must find ways to generate their own power.