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ProjectB.Tech – 07Group – B

PRODUCING ELECTRICITY BY USINGWIND MILL

PRESENTED BY:

ST ZUBAIR, ST ZAHID, ST KASHIF, ST NIAZ, ST SOHAIL, CPL/T ASGHAR

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Wind Mill

Introduction

A windmill is a machine that converts the energy of wind into rotational energy bymeans of vanes called sails or blades. The reason for the name "windmill" is thatthe devices originally were developed for milling grain for food production; thename stuck when in the course of history, windmill machinery was adapted tosupply power for many industrial and agricultural needs other than milling. Themajority of modern windmills take the form of wind turbines used to generateelectricity, or windpumps used to pump water, either for land drainage or toextract groundwater

Major Parts

There are four main parts to a wind turbine: the base, tower, nacelle, and blades.The blades capture the wind's energy, spinning a generator in the nacelle. The

tower contains the electrical conduits, supports the nacelle, and provides access tothe nacelle for maintenance. The base, made of concrete and steel, supports thewhole structure.

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The bladesDesigned like airplane wings, modern wind turbine blades use lift to capture thewind's energy. Because of the blade's special shape, the wind creates a pocket ofpressure as it passes behind the blade. This pressure pulls the blade, causing theturbine to rotate. This modern blade design captures the wind's energy muchmore efficiently than old farm windmills, which use drag, the force of the windpushing against the blades. The blades spin at a slow rate of about 20 revolutionsper minute (RPM).

The nacelle

The nacelle houses a generator and gearbox. The spinning blades are attached tothe generator through a series of gears. The gears increase the rotational speed ofthe blades to the generator speed. As the generator spins, electricity is produced.Generators can be either variable or fixed speed. Variable speed generatorsproduce electricity at a varying frequency. Fixed speed generator aren't as able totake advantage of fluctuations in wind speed.

The towerThe most common tower design is a white steel cylinder, which may be of anylength and diameter as per requirement.

The baseBases are made of concrete reinforced with steel bars. Purpose of base is to holdtower.

Gear BoxThe gearbox converts the rotor motion as per the generator requires. The gearboxthus takes on the task of matching the rotation speeds of the slow-moving rotorand the fast-moving generator, and generally has several steps to cover for variouswind conditions.

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Generator

The generator is what converts the turning motion of a wind turbine's blades intoelectricity. Inside this component, coils of wire are rotated in a magnetic field toproduce electricity. Different generator designs produce either alternating current(AC) or direct current (DC), and they are available in a large range of output powerratings. The generator's rating, or size, is dependent on the length of the windturbine's blades because more energy is captured by longer blades.

It is important to select the right type of generator to match your intended use.Most home and office appliances operate on 120 volt (or 240 volt), 60 cycle AC.Some appliances can operate on either AC or DC, such as light bulbs and resistanceheaters, and many others can be adapted to run on DC. Storage systems usingbatteries store DC and usually are configured at voltages of between 12 volts and120 volts.

Generators that produce AC are generally equipped with features to produce thecorrect voltage (120 or 240 V) and constant frequency (60 cycles) of electricity,even when the wind speed is fluctuating.

DC generators are normally used in battery charging applications and for operatingDC appliances and machinery. They also can be used to produce AC electricity with

the use of an inverter, which converts DC to AC.