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What is the differeance between upwind and downwind turbines?
An Upwind turbine faces into the wind with the turbine blades in front of the Nacelle* while a Downwind turbine has blades to the rear of the Nacelle and faces away from the wind. Up-wind turbines are by far and away the most common, but down-wind turbines (usually two-bladed) are also used in certain situations.In very strong winds the turbine blades of a wind turbine generator flex under enormous forces. With a down-wind turbine the blades flex AWAY from the mast which prevents them from crashing into it. Up-wind turbines need to be designed so that the blades are positioned at a good distance from the mast, and they must also be engineered to be inflexible (which costs more money). In addition, when the blades of a down-wind turbine bend it reduces the stresses on the mast as wind energy is lost in bending the blades. Finally, down-wind turbines do not need a tail (or motorised yaw mechanism) to align them with wind as the turbine blades perform this task (although this can also be a serious disadvantage in large down-wind turbines if wires carrying huge currents are getting twisted).Down-wind turbines on the other hand are generally noisier (additional aerodynamic noise), and the blades are subject to more forces than those of up-wind turbines. Another serious disadvantage of a down-wind turbine is wind shadow behind the mast causing a drop in power each time a blade passed behind the mast.*Nacelle = is located at the top of the mast and contains the rotor and generator, and sometimes a gearbox. Basically it is everything except the turbine blades, tail, and mast.
What are the two types of brakes on a wind turbine?
The controller and mechanical brakes.
What is turbine rated speed and What is maximum speed rise of steam turbine?
Turbine rated speed varies mainaly on the factors of Generating frequency and means of coupling to generator (viz trough a gear box or directly coupled and no.poles in generator). For exmple a 50hz generting frequency and a bi-pole genarator the turbine speed is 3000RPM. The allowed speed rise also depends on turbine design and generator operational range. Generaly the speed rise is restricted to Maximum of 10% of the rated speed.
What is a turbine barring gear?
When a large turbine rotor stops it will still be hot and will tend to bend in the middle if left to cool normally. To prevent this the barring gear will turn the rotor slightly at given intervals during the cool down period.
Do yaw bearings teeth point outward or indward on a wind turbine?
yes
