Figure 5
shows the variation of rotational speed of CB-VAWT with tangential force of the various setting wind
speed of 1.5 – 5.0 m/s. Rotational speeds reach zero with a maximum values of the corresponding
tangential forces. The cut in wind speed is a function of tangential force ratio ( ) as expressed by
Eqn. 5 with the coefficient of determination ( ) of 99.41%. The average error value of Eqn. 5 to
estimation cut in wind speed is 3.99%.