This is the part most important in the wind mill because the turbine converts the mechanical energy into electrical energy. Wind turbine generators are somewhatunusual when compared with other generating units that usually are connected to the mains. One reason is that the generator should work with a power source (the wind turbine rotor) which supplies veryfluctuating mechanical power (torque).
The most typical turbine used for generate electrical power is a electrical engine, also called an induction generator or three-phase asynchronous electricalengine to generate al ternative current, first time this generator was designed to work as a motor and used for driving machinery in factories, pumps, fans, compressors and other industrial applicationswhere we need to transform electrical energy into mechanical energy. The industry was also chosen for their reliability, and is usually not very expensive. The generator also has mechanical propertiesthat make it useful for wind turbines, such as motor slip and a certain overload capability.
In this picture, we can see the different parts of the induction machine that is the same for the woundrotor motor.
Differences between cage rotor and wound rotor induction motor are the next:
Cage rotor (squirrel cage): it consist of a series of conductor bars laid into slots curved in the faceof the rotor and shorted at either end by large shorting rings. This design is referred to as a cage rotor the conductor, if examined by themselves would look like one of the exercise wheels thatsquirrels or hamsters run on.
Wound rotor: it has a complete set of three-phase winding that are mirror images of the winding on the stator. The three-phase of the rotor are usually Y-connected, andthe ends of the three rotor wires are tied to slip rings on the rotor's shaft. The rotor winding are shorted through brushes riding on the slip rings. Wound-rotor induction motors therefore have...