Hydraulic turbine driving generator at variable speed - with output fed to rectifier and oscillator to produce fixed frequency current

摘要

A hydraulic turbine has a rotor with blades (1) of fixed pitch which drives a generator (2). The speed of the turbine varies with the head of water available and consequently the frequency of the generator output also varies. This current of variable frequency is fed to a rectifier (61) which produces d.c. current which is transmitted to an oscillator (62) producing a fixed frequency current of 50 Hz to make it compatible with the mains network (7). This system eliminates the need for a fixed speed turbine with the complication of variable pitch blades.