Power Control Device and Storm Security for Savonius Rotor

The main disadvantage of a Savonius rotor has been its failure to control its power and survive in high winds. A built-in device is developed that provides automatic power control and storm security. This consists of a window on each cup of the Savonius and its springloaded shutter that opens centrifugally when a certain rpm is exceeded. A technique for power measurement that employs a wind tunnel balance and the brake-dynamometer principle is developed. A rotor with this device is tested in a wind tunnel under different brake loads, spring tensions and wind speeds. The shutters open reliably to limit rpm and power; the open shutters reduce drag on the rotor and these features should offer protection from centrifugal forces and wind thrust in a storm. Increased shutter spring tension resulted in higher power coefficient. The rotor could not be subjected to extreme winds in the wind tunnel for reasons of safety.