1. This allows the variation of the rotor speed independent of generator speed. 2. Varying the rotor speed may induce severe vibrations at specific resonance frequencies. 3. It can also be seen from considering the torque-rotor speed diagram. 4. Here, the relative wind does not decrease; rather, it increases with rotor speed . 5. This type of aerodynamic noise is mostly low frequency determined by the rotor speed . 6. The rotor speed can either be increased or decreased by an appropriately designed controller. 7. To obtain higher frequencies, higher rotor speeds were required, up to 20, 000 RPM. 8. However, as the rotor speed increases, the noise levels increase. 9. In many piston engine-powered helicopters, the pilot manipulates the throttle to maintain rotor speed . 10. From the above equation, we can construct a torque-rotor speed diagram for a wind turbine.
