Old Wind Turbine Technology

Wind powered water pumping systems has been attempted on Lubang Island before. The photo's show wind systems that were installed about 20 years ago by a German Catholic priest on the island. The systems were installed for potable water usage and irrigation of rice fields. Unfortunately neither system survived longer than a few hours operation and they have been left to rust.

Mechanical wind system at Looc for rice field irrigation.

Both are mechanical wind systems, unlike SIBATs electrical turbine. The mechanical power from the rotation of the blades is transferred to a vertical shaft running down the centre of the tower to a pump. The main advantage of this type of design is that the machine can operate at low wind speeds. The start up wind speed is low due to the many blades, providing greater torque and slower rotational velocity than the 3 blade systems. However, the system is not appropriate to areas with strong wind and typhoons as the system easily 'runs away'. The massive torque from the blades in high wind speeds puts too much stress on the shaft and bevel gears, in the case of Lubang, causing almost instant fracture. In Cabra the wind turbine has been completely destroyed leaving just the rusty tower to support the pulley which the community use to haul 4 gallon containers of water up 37m to the surface.

Mechanical wind system at Cabra for potable water

There are a number of advantages of the 3 blade electrical wind turbine over this type of design:

- The electricity generated by the wind turbine is not restricted to water pumping

- More energy can be harnessed as the wind turbine is designed to operate in higher wind speeds (energy in the wind is proportional to the cube of the wind speed)

- The tower can be higher (as power is tranferred by wire rather than a shaft), allowing the wind turbine to be placed in stronger winds

- The wind turbine can be easily lowered for protection during typhoons and maintenance

- For water pumping, the wind turbine does not have to be placed directly above the well