Friends, today in this article we will learn about the parts of a windmill with low load angle generator. I am going to give information about all these in a very good way. So let’s start.
Guide Wire – Vertical axis wind turbines usually require guide wire to hold the rotor shaft in a fixed position and to minimize possible mechanical vibration.
Hub – The hub is the centre of the rotor to which the rotor blades are attached. Cast iron or cast steel is most commonly used for this. A VAWT has two hubs, upper and lower, because the blades are attached at two points.
Rotor – The rotor is the main part of a wind turbine and consists of a number of rotor blades attached to a hub. It is the turbine component responsible for collecting the energy in the wind and converting this energy into mechanical motion. As the overall diameter of the rotor design increases, the amount of energy the rotor can extract from the wind also increases. Therefore turbines are often designed to suit a certain rotor diameter and the estimated energy that can be extracted from the wind.
Rotor Blade – Rotor blades are an important and fundamental part of a wind turbine. They are primarily made of aluminum, fiberglass or carbon fiber as they provide a higher strength to weight ratio. The design of individual blades also affects the overall design of the rotor. Rotor blades extract energy from the wind, they “capture” the wind and convert its kinetic energy into rotation of the hub. Two types of blades are used in VAWT-
(i) Dredge force type blades (Savonius wind turbine)
(ii) Lift force type blades (Darrieus and Giromil wind turbines)
- Shaft – The shaft is the part that is rotated by the turbine blades. It is attached to the generator within the main housing.
- Brake-
(i) Electrical braking – Braking of a small wind turbine can be done by dumping energy from the generator into a resistor bank or by converting the kinetic energy of turbine rotation into heat. This method is useful where the kinetic load on the generator is suddenly reduced. Cyclic braking slows down the blades, increasing the stalling effect, and reducing the efficiency of the blades. Thus, by electrical braking, the turbine rotation can be maintained at a safe speed in high winds, while maintaining the nominal power output. This method is not usually applicable to large grid-connected wind turbines.
(ii) Mechanical Brake- A mechanical brake is usually placed on the high speed shaft between the gearbox and the generator, but there are some turbines which have the mechanical brake placed on the low speed shaft between the turbine and the gear box.
A mechanical drum brake or disc brake is used to stop the turbine in an emergency, such as overspeed. This brake is also used as a secondary means to stop the turbine at rest for maintenance, i.e. primarily by means of a rotor lock system. Such brakes are usually applied only after blade furling and the turbine speed is usually reduced by 1 or 2 rotor-RPM by the use of electromagnetic braking, as mechanical brakes can cause fire inside the nacelle if used to stop the turbine at full speed. The load on the turbine also increases if the brake is applied at rated RPM. This type of mechanical brake is operated by the hydraulic system and is connected to the main control box.
Gear Box – The main function of the gear box is to increase the rotational speed of the generator by taking the low rotational speed from the shaft. The types of gear stages are plantary, helical, oral shaft, spur and worm types. Two or more gear types can be combined to form multiple stages. They are made of aluminum alloy, stainless steel and more costly iron.
Generator – The conversion of rotational mechanical energy into electrical energy is done by a generator. Various types of generators have been used over the years in wind power systems. For large, commercial sized horizontal axis wind turbines, the generator is mounted in a nacelle at the top of the towbar, behind the hub of the turbine rotor. Wind turbines usually generate electricity through asynchronous machines that are directly connected to the electricity grid. Typically the rotation speed of a wind turbine is slower than the equivalent rotation speed of the electrical network. Typical rotation speeds for wind generators are 5-20 RPM while direct connected generators have electric rotation speeds between 750-3600 RPM. Therefore, a gearbox is inserted between the rotor hub and the generator. This also reduces the cost and weight of the generator.
Base – The base of a VAWT is usually the roof of the building on which it is installed.
What did you learn today :-
Now you must have known the parts of windmill with low load angle generator and you must have got the answer to all these questions well.
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