Patent ID: 9562512
Date: 2017-02-07
CPC Classifications: F03B,F03D,F05B,Y02E

Claim:
1. A dual rotor arrangement for a wind or water turbine comprising: a planetary gearbox having a first input connected to a first rotor, a second input connected to a second rotor, and an output connected to a generator, and in which said first rotor and second rotor comprise blades having a variable pitch; wherein said output is coaxial with an axis around which the first and second rotors rotate, said first input is connected to a ring gear of said planetary gearbox, said second input is connected to a planet carrier of said planetary gearbox, said output is connected to a sun gear of said planetary gearbox, said first rotor is upstream of said planetary gearbox and said second rotor is downstream of said planetary gearbox; wherein, in use, a rotational speed of said output is determined by a relative rotational speed of said first and second rotors and controlled by an angular position of said blades so that said generator produces electricity of a desired frequency under conditions where a speed of said wind or water is variable.