Intermediate Technology Development Group – Sri Lanka
Nearly 40% of Sri Lankan households do not have access to electricity supply through the national grid. Many of them are located in rural areas where the grid extension is often found to be uneconomical. This is primarily due to the low energy demand in most rural households coupled with the high cost of extending and maintaining the grid supply lines.
In 1998, Intermediate Technology Development Group (ITDG) launched a project to develop a small battery charging wind generator, which could cater to the needs of rural households. Design and development of this machine was contracted to RMA.
In June 2000, the first prototype was fabricated and subjected to a rapid assessment of the performance of the rotor and speed control system using the technique of Controlled Velocity Testing (CVT). This was performed in Ussangoda, a flat open tract of land overlooking the southern coast. A wind data logger and digital power monitoring meters were used to collect the data. The system consists of a two bladed wind turbine that drives the 200W Permanent Magnet Generator (PMG) of “air gap type”. AC supply from the PMG is rectified and used to charge the battery. The battery supplies AC electricity to the household through a 400W inverter.
The prototype machine is now running in a southern village called Andarawewa, Once the testing phase is completed, RMA will develop the production model and train local workshops in the manufacture of this wind turbine.