The main controller of the Turbine is the governor. The motion of the turbine can be fully controlled by changing the flow rate of the water supplied. In Francis and Kaplan Turbines servo motor operated wicket gates which are controlled by the governor are used for this purpose.
Applications of the Governor
1. Speed control at no load operation before synchronizing
2. Power output control with ALR after synchronizing
3. Frequency regulation
4. Isolated operation
5. Spinning reserve operation