MAGNETICALLY LEVITATED VERTICAL AXIS WIND TURBINE

Project report submitted in partial fulfillment of the requirement for the award of degree of BACHELOR OF TECHNOLOGY

IN

MECHANICAL ENGINEERING

Submitted By

K GOPI NATA - 09241A0364

K PRADEEP - 09241A0381

G PRADEEP KUMAR - 09241A0382

M S SANKETH - 09241A03A5

Under the Guidance of

Dr. ADAPA RAMA RAO Prof & Dean, Counseling and Career Guidance

Department Of Mechanical Engineering

Gokaraju Rangaraju Institute of Engineering and Technology

Bachupally, Hyderabad 500 090, A.P, India

April, 2013

Gokaraju Rangaraju Institute of Engineering and Technology

(Affiliated to Jawaharlal Nehru Technological University)

HYDERABAD

CERTIFICATE

This is to certify that the Project Report entitled MAGNETICALLY

LEVITATED VERTICAL AXIS WIND TURBINE being submitted by K GOPI NATA

(09241A0364); K PRADEEP (09241A0381); G PRADEEP KUMAR (09241A0382);

M SRIVATHSA SANKETH (09241A03A5) in partial fulfillment for the award of B.Tech

in Mechanical Engineering to the department of Mechanical Engineering; Gokaraju

Rangaraju Institute of Engineering and Technology; affiliated to Jawaharlal Nehru

Technological University, Hyderabad is a record of bonafide work carried out by them under

our guidance and supervision.

The results embodied in this Project Report have not been submitted to any

other University or Institute for the award of any degree or diploma.

Guide :

Dr. ADAPA RAMA RAO

Dean & Professor

ACKNOWLEDGEMENT

It is a pleasure to express thanks to Dr. ADAPA RAMA RAO for the encouragement

and guidance throughout the course of this project.

We would like to express our heartfelt gratitude and appreciation to

Dr. ADAPA RAMA RAO of the Mechanical Department for his relentless patience

and guidance throughout every phase of the project. His impressive intellection and

insightfulness was a major contributing factor to the success of this project.

I am grateful to our principal Dr. JANDHYALA N MURTHI who most ably run the

institution and has had the major hand in enabling me to do my project.

I profoundly thank Dr. K.G.K. MURTHI, Head of the Department of Mechanical

engineering who has been an excellent guide and also a great source of inspiration to

my work and also Dr. P.A.P. NAGENDRA VARMA under whose kind supervision

we accomplished our Project.

I would like to thank my internal guide Dr. ADAPA RAMA RAO once again for his technical guidance, constant encouragement and support in carrying out my project at

college.

The satisfaction and euphoria that accompany the successful completion of the task

would be great but incomplete without the mention of the people who made it

possible with their constant guidance and encouragement crowns all the efforts with

success.

K GOPINATA K PRADEEP 09241A0364 09241A381

G PRADEEP KUMAR M S SANKETH

09241A0382 09241A03A5

ABSTRACT

This project dwells on the implementation of an alternate configuration of a

wind turbine for power generation purposes.. A vertical axis wind turbine (VAWT) is

introduced by magnetic levitation technology to optimize the performance. The

system utilize nature of permanent magnet as a replacement for ball bearings to

levitate the turbine component and thus minimize energy losses while rotating, which

is the major problem that faced by conventional wind turbine. The Maglev Wind

Turbine is expected to bring wind power technology to the next level. Furthermore,

the system can be suited in use for rural and urban areas of low wind speed regions.

The selection of magnet materials in the design of wind turbine system will be

discussed. A model of wind turbine is built to perform several tests such as starting

wind speed, rotational speed at constant wind speed, and time taken to stop rotation

completely. The results obtained will be compared with the model of conventional

wind turbine. Power will then be generated with an axial flux generator, which

incorporates the use of permanent magnets and a set of coils.

CONTENTS

INTRODUCTION 01

LITERATURE REVIEW 03

IMPORTANCE OF PROJECT 06

DESCRIPTION OF PROJECT 07

CHAPTER 01 :

1.1 CHARACTERISTICS OF WIND TURBINES 09

1.2 SITE SELECTION CONSIDERATIONS 10

1.3 MATERIALS USAGE IN WIND TURBINES 12

CHAPTER 02 :

2.1 TYPES OF WIND TURBINES 16

2.2 MAJOR COMPONENTS OF A WIND TURBINE 18

2.3 WIND FORCE 19

CHAPTER 03 :

3.1 WORKING PRINCIPLE 23

3.2 COMPONENTS SELECTION 26

CHAPTER 04 :

4.1 ABOUT CATIA 31

4.2 DESIGN OF WIND TURBINE 33

CHAPTER 05:

5.1 FABRICATION TECHNIQUES 42

5.2 WIND TURBINE BLADE HUB ASSEMBLY 46

5.3 PROTOTYPE COMPONENTS 47

5.4 ACCESSORIES USED 51

CHAPTER 06:

6.1 TEST PROCEDURE 54

6.2 TEST RESULTS AND DISCUSSION 55

CONCLUSION 58

REFERENCES 59

LIST OF FIGURES

S.No Figure

Number Name of the figure Page no.

1 2.1 HAWT Configuration 16

2 2.2 VAWT Configuration 17

3 2.3 Typical Wind Turbine Major Components 18

4 3.1 MAGLEV concept (with ring magnets for shaft) 23

5 4.1 Drafting Sheet - Levitation Magnets 34

6 4.2 Catia - Product Design - Levitation Magnets 34

7 4.3 Drafting Sheet - Turbine Blade 35

8 4.4 Catia - Product Design - Turbine Blade 35

9 4.5 Drafting Sheet - Turbine Shaft 37

10 4.6 Catia - Product Design - Turbine Shaft 37

11 4.7 Drafting Sheet - Turbine Base 38

12 4.8 Catia - Product Design - Turbine Base 38

13 4.9 Drafting Sheet - Magnet sleeve 39

14 4.10 Catia - Product Design - Magnet Sleeve 39

15 4.11 Catia - Turbine Blade hub assembly 40

16 5.1 Turbine Base with fixed stepped shaft 47

17 5.2 Magnet Sleeve 47

18 5.3 Blade hub 48

19 5.4 Rotor 48

20 5.5 Rotor integrated to Turbine head & setup on rigid base

49

21 5.6 Magnetic Levitation in progress 49

22 5.7 Stator in alignment to rotor 50

23 5.8 Multimeter M830B 51

24 5.9 YAMAYO Vernier Callipers 51

25 5.10 Spirit Level 52

LIST OF TABLES

S.No Table

Number Table Page no.

1 6.1 Test 1: The starting wind speed of wind turbine model

55

2 6.2 Test 2: The rotational speed of wind turbine model at constant wind speed

55

3 6.3 Test 3: The time taken by wind turbine model to stop rotation

55

LIST OF GRAPH

S.No Graph Graph Page no.

1 1.1 Power Generation 2010 - 2013 01

2 3.1 B-H Curve of Various Magnetic Materials 28

INTRODUCTION

Nowadays, we will ultimately need to search for renewable or virtually

inexhaustible energy for the human development to continue. Renewable energy is

generally electricity supplied from sources, such as wind power, solar power,

geothermal energy, hydropower and various forms of biomass. These sources have

been coined renewable due to their continuous replenishment and availability for use

over and over again.

The popularity of renewable energy has experienced a significant upsurge in

recent times due to the exhaustion of conventional power generation methods and

increasing realization of its adverse effects on the environment. The exploration of

renewable energy is the only approach to reduce our dependence on fossil fuels.

Among the renewable energy sources Wind Energy is one of the fastest growing

energy sources which is growing at the rate of 30% annually [1].

Graph 1.1 : Power Generation 2010 - 2013

Wind energy was first harvested centuries ago, when early windmills were

used to power millstones, pumps, and forges. More recently, the wind is harnessed by

using a special collector, called wind turbine to produce a clean, safe source of

electricity. Various designs have been proposed in order to create a high efficient

wind turbine which will be able to generate maximum electric power. They may vary

either in the design of shape of the turbine blades, the axis of rotation, and other

useful modification.

The wind speeds in most of Asian zone is much lower than 7 m/s, especially in

the cities, but the mechanical frictional resistance of existing wind turbines is too big,

usually it can't start up when the wind speed is not big enough. This project introduces

structure and principle of the proposed magnetic levitation wind turbine for better

utilization of wind energy. Maglev Wind turbine has the features of no mechanical

contact, no friction etc. minimizing the damping in the magnetic levitation wind

turbine, which enables the wind turbine start up with low speed wind and work with

breeze. The Maglev wind turbine, which was first unveiled at the Wind Power Asia

exhibition in Beijing, is expected take wind power technology to the next level with

magnetic levitation [2].

The aim of this major qualifying project is to design and integrate an advance

technique, Magnetic Levitation(Maglev) into turbine system in order to increase the

efficiency. If the efficiency of a wind turbine is increased, then more power can be

generated thus decreasing the need for expensive power generators that cause

pollution. Since one of the main complaints about wind turbines is the sound they

produce, this is a huge advantage over other turbine designs.

LITERATURE REVIEW

Wind Energy

Wind is known to be another form of solar energy because it comes about as a

result of uneven heating of the atmosphere by the sun coupled with the abstract

topography of the earths surface. With wind turbines, two categories of winds are

relevant to their applications, namely local winds and planetary winds. The latter is

the most dominant and it is usually a major factor in deciding sites for very effective

wind turbines [3].

There are some reasons to support in using the wind energy to produce

electricity power. Wind power available in the atmosphere is much greater than

current world energy consumption. The exploitation of wind power is only limited by

the economic and environmental factors, since the resource available is far larger than

any practical means to develop it. Renewable energy produced from the wind has

attracted a lot of attention and support in recent years. However, this green energy is

often criticized for its low output and lack of reliability.

Wind Turbine

The basic working principle of a wind turbine is: When air moves quickly, in

the form of wind, and their kinetic energy is captured by the turbine blades. The

blades start to rotate and spin a shaft that leads from the hub of the rotor to a generator

and produce electricity. In general, they are two types of wind turbine according to the

axis they are rotating about. Horizontal axis wind turbine (HAWT) is the type of wind

turbine which has a main rotor shaft and electrical generator at the top of tower and

pointed to the direction of wind. Most of them possess a gear box which turns the

slow rotation of turbine blades into faster rotation that is more suitable to drive an

electrical generator.

As for the Vertical axis wind turbine (VAWT) consists of generator and

gearbox which are placed at the ground and thus there is no need for a tower to

support them as in HAWT. The main rotor shaft is arranged vertically to allow the

turbine blades rotate without facing to the direction of the wind. In VAWT system,

the generator and gearbox is placed on the ground rather than on the top. There is no

need of the support from a tower make it more accessible for maintenance.

Magnetic Levitation

Magnetic levitation (maglev) is a method in which an object is suspended with

no support other than magnetic fields. The magnetic force produced is used to

counteract the effects of the gravitational force and lift up the object.

By placing these two magnets on top of each other with like polarities facing

each other, the magnetic repulsion will be strong enough to keep both magnets at a

distance away from each other. The force created as a result of this repulsion can be

used for suspension purposes and is strong enough to balance the weight of an object

depending on the threshold of the magnets

There are many advantages for utilizing magnetic levitation that is to

minimize friction, make force measurement, design, and entertaining devices.

Recently, this advance technology is applied into transportation system in which non

contacting vehicle travel safely at very high speed while suspended, guided, and

propelled above a guide way by magnetic fields. The concept of magnetically

levitated vehicle stimulates the development of useful application in various fields

such as the power generation.

Maglev Wind Turbine

The vertically oriented blades of the wind turbine are suspended in the air

above the base of the machine by using permanent magnet which produces magnetic

force to lift up the blades. This system does not require the electricity to operate

because no electromagnets are involved. Since the turbine blades are suspended by

magnetic force produce by the permanent magnet, there is no need of ball bearing to

retain the blades. This allows the friction between the blades and ball bearing can be

reduced significantly and thus, minimizes the energy loss. This also helps reduce

maintenance costs and increases the life span of the generator.

Generator

The basic understanding of a generator is that it converts mechanical energy to

electrical energy. Generators are utilized extensively in various applications and for

the most part have similarities that exist between these applications. Over the years,

alternating current has been the common choice of power supply. AC is popular

because the voltage can be easily stepped up or down using a transformer. Due to the

inherent properties of a transformer, DC voltage cannot be altered using this type of

equipment. Transformers operate due to a changing magnetic field in which the

change in magnetic flux induces a current.

With the AC flux generator design, its operability is based on permanent

magnet alternators where the concept of magnets and magnetic fields are the

dominant factors in this form of generator functioning. These generators have air gap

surface parallel to the rotating axis and the air gap generates magnetic fluxes

perpendicular to the axis.

IMPORTANCE OF PROJECT

As a efficient upgrade this project prefers an advanced technique, Magnetic

levitation for Wind Energy Power Generation. Maglev wind turbines have several

advantages over conventional wind turbines. Theyre able to use winds with starting

speeds as low as 4.5 meters per second (m/s). Also, they could operate in winds

exceeding 40 m/s. It would also increase generation capacity by 20% over

conventional wind turbines and decrease operational costs by 50%. This make the

efficiency of the system become higher than the conventional wind turbine The

maglev wind turbines will be operational for about 100 years [4].

Unlike the traditional horizontal axis wind turbine, this design is levitated via

maglev (magnetic levitation) vertically on a rotor shaft. This maglev technology

serves as an efficient replacement for ball bearings used on the conventional wind

turbine and is implemented with permanent magnets. This levitation will be used

between the rotating shaft of the turbine blades and the base of the whole wind turbine

system.

The turbine uses permanent type of rare earth magnets (neodymium), not

electromagnets and therefore, it does not require electricity to run. This friction

between the turbine blades and the base can be reduced significantly and thus

produces maximum power output.

DESCRIPTION OF PROJECT

Magnetic levitation weight reduction structure for a vertical wind turbine

generator includes a frame, a fixed permanent magnet, an axle, a revolving permanent

magnet, a blade hub, and a generator. The fixed permanent magnet fixed to the frame

has a first repulsive surface. The axle is connected to the frame. The revolving

permanent magnet fixed to the axle has a second repulsive surface in relation to the

first repulsive surface of the fixed permanent magnet. Both the first and the second

repulsive surfaces repel with each other. The blade hub and the generator are

connected to the axle. When the revolving permanent magnet is rotated, the axle

functions as a balance center. An out structure supports the stator and the rotor is

placed over turbine head.

The main components of the system is the maglev zone, blade hub and

Auxiliary Current (AC) generator. It will convert the kinetic energy from the wind to

the electricity for usage.

A modified roof ventilator is used as wind turbine. The main function of the

free spinning roof ventilator is to provide fresh air in roof space and living area all

year round 24 hours a day free of charge. The new idea of the magnetic levitation

helps to improve the turbine speed and electrical production. This modification has

benefits of the better air ventilation, but also have extra electricity supply for load

appliances.

The concept behind wind turbine vents is that the turning blades will help

force air out of the attic. The blades or vanes are shaped to allow for maximum wind

catching ability, resulting in rotation at minimal winds speeds of 8kph or lower.

CHAPTER - 01

1.1 CHARACTERISTICS OF WIND TURBINES

Wind Speed

This is very important to the productivity of a windmill. The wind turbine only

generates power with the wind. The wind rotates the axis (horizontal or vertical) and

causes the shaft on the generator to sweep past the magnetic coils creating an electric

current.

Blade Length

This is important because the length of the blade is directly proportional to the

swept area. Larger blades have a greater swept area and thus catch more wind with

each revolution. Because of this, they may also have more torque.

Base Height

The height of the base affects the windmill immensely. The higher a windmill

is, the more productive it will be due to the fact that as the altitude increases so does

the winds speed.

Base Design

Some base is stronger than others. Base is important in the construction of the

windmill because not only do they have to support the windmill, but they must also be

subject to their own weight and the drag of the wind. If a weak tower is subject to

these elements, then it will surely collapse. Therefore, the base must be identical so as

to insure a fair comparison.

1.2 SITE SELECTION CONSIDERATIONS

The power available in the wind increases rapidly with the speed; hence wind

energy conversion machines should be located preferable in areas where the winds are

strong & persistent. The following point should be considered while selecting site for

Wind Energy Conversion System (WECS) [5].

High annual average wind speed

The wind velocity is the critical parameter. The power in the wind Pw, through a

given X section area for a uniform wind Velocity is

Pw = KV3 (K is constant)

It is evident, because of the cubic dependence on wind velocity that small increases in

velocity markedly affect the power in the wind.

e.g. doubling V, increases Pw by a factor of 8.

Availability of wind V(t) curve at the proposed site

This important curve determines the maximum energy in the wind and hence is the

principle initially controlling factor in predicting the electrical o/p and hence revenue

return of the WECS machines, it is desirable to have average wind speed V such that

V12-16 km/hr i.e. (3.5 4.5 m/sec).

Wind structures at the proposed site

Wind especially near the ground is turbulent and gusty, & changes rapidly indirection

and in velocity. This departure from homogeneous flow is collectively referred to as

the structure of the wind.

Altitude of the proposed site

If affects the air density and thus the power in the wind & hence the useful WECS

electric power o/p. The winds tends to have higher velocities at higher altitudes.

Local Ecology

If the surface is bare rock it may mean lower hub heights hence lower structure cost,

if trees or grass or ventation are present. All of which tends to de-structure the wind.

Nearness of site to local center/users

This obvious criterion minimizes transmission line length & hence losses & costs.

Nature of ground

Ground condition should be such that the foundations for WECs are secured, ground

surface should be stable.

Favorable land cost

Land cost should be favorable as this along with other sitting costs, enters into the

total WECS system cost.

1.3 MATERIALS USAGE IN CURRENT WIND TURBINES

A wide range of materials are used in wind turbines. There are substantial

differences between small and large machines and there are projected changes in

designs that will accommodate the introduction of new material technologies and

manufacturing methods. To arrive at a total, the material usage is weighted by the

estimated market share of the various manufacturers and machines types. In general

the materials used for wind turbines are Steel, Aluminum, Copper and Plastic [6].

Properties of aluminium [7] :

Physically, chemically and mechanically aluminium is a metal like steel, brass,

copper, zinc, lead or titanium. It can be melted, cast, formed and machined much like

these metals and it conducts electric current. In fact often the same equipment and

fabrication methods are used as for steel.

Light Weight

Aluminium is a very light metal with a specific weight of 2.7 g/cm3, about a third

that of steel. For example, the use of aluminium in vehicles reduces dead-weight

and energy consumption while increasing load capacity. Its strength can be

adapted to the application required by modifying the composition of its alloys.

Corrosion Resistance

Aluminium naturally generates a protective oxide coating and is highly corrosion

resistant. Different types of surface treatment such as anodizing, painting or

lacquering can further improve this property. It is particularly useful for

applications where protection and conservation are required..

Electrical and Thermal Conductivity

Aluminium is an excellent heat and electricity conductor and in relation to its

weight is almost twice as good a conductor as copper. This has made aluminium

the most commonly used material in major power transmission lines.

Reflectivity

Aluminium is a good reflector of visible light as well as heat, and that together

with its low weight, makes it an ideal material for reflectors in, for example, light

fittings or rescue blankets.

Ductility

Aluminium is ductile and has a low melting point and density. In a molten

condition it can be processed in a number of ways. Its ductility allows products of

aluminium to be basically formed close to the end of the products design.

Impermeable and Odourless

Aluminium foil, even when it is rolled to only 0.007 mm thickness, is still

completely impermeable and lets neither light aroma nor taste substances out.

Moreover, the metal itself is non-toxic and releases no aroma or taste substances.

Recyclability

Aluminium is 100 percent recyclable with no downgrading of its qualities. The re-

melting of aluminium requires little energy: only about 5 percent of the energy

required to produce the primary metal initially is needed in the recycling process.

Strength

Aluminium is strong with a tensile strength of 70 to 700 MPa depending on the

alloy and manufacturing process. Extrusions of the right alloy and design are as

strong as structural steel.

Elasticity

The Youngs modulus for aluminium is a third that of steel (E = 70,000 MPa).

This means that the moment of inertia has to be three times as great for an

aluminium extrusion to achieve the same deflection as a steel profile.

Formability

Aluminium has a good formability, a characteristic that is used to the full in

extruding. Aluminium can also be cast, drawn and milled.

Machining

Aluminium is very easy to machine. Ordinary machining equipment can be used

such as saws and drills. Aluminium is also suitable for forming in both the hot and

the cold condition.

Joining

Aluminium can be joined using all the normal methods available such as welding,

soldering, adhesive bonding and riveting.

Conductivity

The thermal and electrical conductivities are very good even when compared with

copper. Furthermore, an aluminium conductor has only half the weight of an

equivalent copper conductor.

Linear expansion

Aluminium has a relatively high coefficient of linear expansion compared to other

metals. This should be taken into account at the design stage to compensate for

differences in expansion.

CHAPTER - 02

2.0 WIND POWER TECHNOLOGY

Wind power technology is the various infrastructure and process that promote the

harnessing of wind generation for mechanical power and electricity [8].

2.1 TYPES OF WIND TUBINE

Many types of turbines exist today and their designs are usually inclined

towards one of the two categories: horizontal-axis wind turbines (HAWTs) and

vertical-axis wind turbines (VAWTs). As the name pertains, each turbine is

distinguished by the orientation of their rotor shafts. The former is the more

conventional and common type everyone has come to know, while the latter due to its

seldom usage and exploitation, is quiet unpopular. The HAWTs usually consist of two

or three propeller-like blades attached to a horizontal and mounted on bearings the top

of a support tower.

fig 2.1 - HAWT Configuration

When the wind blows, the blades of the turbine are set in motion which drives

a generator that produces AC electricity. For optimal efficiency, these horizontal

turbines are usually made to point into the wind with the aid of a sensor and a servo

motor or a wind vane for smaller wind turbine applications.

With the vertical axis wind turbines, the concept behind their operation is

similar to that of the horizontal designs. The major difference is the orientation of the

rotors and generator which are all vertically arranged and usually on a shaft for

support and stability. This also results in a different response of the turbine blades to

the wind in relation to that of the horizontal configurations.

fig 2.2 - VAWT Configuration

Their design makes it possible for them to utilize the wind power from every

direction unlike the HAWTs that depend on lift forces from the wind similar to the lift

off concept of an airplane.

The functioning of this model is dependent on drag forces from the wind. This

drag force produced is a differential of the wind hitting by the inner part of the scoops

and the wind blowing against the back of the scoops.

2.2 MAJOR COMPONENTS OF A WIND TURBINE

A wind turbine basically draws the kinetic energy from the wind and converts

this power to electrical energy by means of a generator. Its operability is dependent on

key components of the turbine and its response to the wind based on how it is built.

fig 2.3 - Typical Wind Turbine Major Components

The blades receive the wind and are caused to lift and rotate. Depending on

the wind speed the controller will start up or shut off the turbine. If wind speeds are

right between 8 to 16 miles per hour, the turbine would start to operate but will shut

down if speeds exceed about 55 miles per hour. This is a preventative measure

because at very high winds the turbine could be damaged. The anemometer on the

turbine calculates this wind speed and sends the information to the controller. The

VAWTs usually do not have anemometers because they are usually used for low

speed and small scale applications. The high speed shaft drives the generator to

produce electricity and they are connected to the low speed shaft by gears to increase

their rotational speed during operation. Most generators usually require a rotational

speed of about 1000 to 1800 rotations per minute so the gears increases them

significantly from 30 to 60 rotations per minute to the electricity producing threshold.

All these components sit on a tower usually made out of steel or concrete. The height

of the tower is dependent on the size of the rotors and the desired amount of

electricity generation. Taller towers serve as an advantage because wind speed is

abundant with height so the rotors will work well with increased tower height and

promote more and efficient electricity generation.

2.3 WIND FORCE

The power in the Wind

The effective functioning of a wind turbine is dictated by the wind availability

in an area and if the amount of power it has is sufficient enough to keep the blades in

constant rotation. The wind power increases as a function of the cube of the velocity

of the wind and this power is calculable with respect to the area in which the wind is

present as well as the wind velocity [9]

Kinetic Energy (K.E) = mv2

Amount of Air passing is given by

m = AV ..(1)

Where

m = mass of air transversing

A=area swept by the rotating blades of wind mill type generator

= Density of air

V= velocity of air

Substituting this value of the mass in expression of K.E.

K.E= AV.V2 watts

K.E= AV3 watts .. (2)

To convert the energy to kilowatts, a non-dimensional proportionality constant k is

introduced where,

k = 2.14 X 10-3

Therefore

Power in KW (P) = 2.14 AV3 X 10-3

where

Air Density () = 1.2 kg/m3

Area (A) = area swept by the blades of the turbine

Velocity (V) = wind speed

With equation above, the power being generated can be calculated, however

one should note that it is not possible to convert all the power of the wind into power

for generation.

The power harnessed from the wind cannot exceed 59% of the overall power

in the wind. Only a portion can be used and that usable portion is only assured

depending on the wind turbine being used and the aerodynamic characteristics that

accompany it.

The drag force acting on one blade

The turbine absorbs the wind energy with their individual blade will move

slower that the wind velocity. The different speed generates a drag force to drive the

blades. The drag force Fw acting on one blade is calculated as [10]

Fw = [ Cd A (Uw - Ub )2 ] / 2

where

A is swept area of the blade

is air density (about 1.225kg/m3 at sea level)

Uw is wind speed

Cd is the drag coefficient (1.9 for rectangular form)

Ub is the speed on the blade surface.

It is seen that the wind velocity Uw dominates the wind force as compared to

other parameters A, Cd and . As expected, more driving force Fw is easily and

effectively to rotate the turbine and to gain more electricity eventually. The maximum

power is obtained while

Ub = Ub / 3

CHAPTER - 03

3.1 WORKING PRINCIPLE

3.1.1 MAGLEV

The characteristic that set this wind generator apart from the others is that it is

fully supported and rotates about a vertical axis. This axis is vertically oriented

through the center of the wind vent which allows for a different type of rotational

support rather than the conventional ball bearing system found in horizontal wind

turbines. [11]

fig 3.1 : MAGLEV concept (with ring magnets for shaft)

It seems that levitation would be most effective directly on the central axis line

where, under an evenly distributed load, the wind turbine center of mass will be found

as seen in Figure. This figure shows a basic rendition of how the maglev will be

integrated into the design. If the magnets where ring shaped then they could easily be

slid tandem down the shaft with the like poles facing toward each other. This would

enable the repelling force required to support the weight and force of the wind turbine

and minimize the amount of magnets needed to complete the concept.

3.1.2 WIND VENT

The ventilators works on two simple principals, The wind velocity &

temperature & convection. The wind-powered ventilator operates mainly by utilizing

wind velocity. The blades are very lightweight & therefore even slightest breeze

causes turbine to spin.

The wind-operated ventilator creates a region of low pressure under the

turbine caused by centrifugal force of spinning blades. The airflows from high-

pressure area to low-pressure area, the hot air fumes & smoke is driven out through

the turbine & continuously replaced by outside fresh air. Secondly temperature

difference between the outside & inside of factory shed, warehouse, building etc.

causes a difference in air density, which in turn causes difference in air pressure. Even

when the wind does not blow, due to the convection effect, the turbine keeps

spinning.

3.1.3 GENERATOR

An important factor to note in generators is that the greater the change in

magnetic field the greater the induced voltage. Translating this to the construction of a

wind turbine is that the greater the velocity of the wind the greater the rate of change

in the magnetic field and hence more voltage will be produced. Faraday discovered

that the induced voltage was not only proportional to the rate of change in the

magnetic field but it is also proportional to the area of the magnetic field. This area

directly relates to the size of each coil in a generator or the area of a coil. Increasing

the size of each coil will proportionally increase the voltage output. [13]

There are three ways to induce a voltage. The first way is to change the

magnetic field. The axial flux generator, which we are designing, utilizes the

changing magnetic field produced by the magnets to induce a voltage. The rotating

magnets pass over a number of coils each producing their own voltage. The second

way is to change the area of an individual coil in a magnetic field. The third and final

way is to change the angle between the coil and the magnetic field. Many generators

today use this method to induce a voltage. Some of these generators rotate the coils in

a field and others rotate the field around stationary coils.

The number of windings per coil produces a design challenge. The more

windings will increase the voltage produced by each coil but in turn it will also

increase the size of each coil. In order to reduce the size of each coil a wire with a

greater size gage can be utilized. Again another challenge is presented, the smaller the

wire becomes less current flow before the wire begins to heat up due to the increased

resistance of a small wire [12].

3.2 COMPONENTS SELECTION

3.2.1 NEODYNIUM MAGNETS

In selecting the vertical axis concept for the wind turbine that is implemented as the

power generation portion of this project, a certain uniqueness corresponded to it that

did not pertain to the other wind turbine designs.

The amount of magnetic force that needs to counteract the weight of the wind

turbine must be determined before the type of magnet material is selected.

From the law of attraction

F = GW1W2/r2

Then, the equation is rewritten as below to calculate the magnetic force between

two poles.

F = 0 Qm1 Qm2 / 4r2

where

F : Magnetic force, N

Qm1, Qm2 : Magnetic poles, A.m

0 : Permeability of free space 4 x 10-7 N/A2

R : Distance between two poles, m

The magnetic poles of the magnet can be calculated by using following equation

Qm1,m2 = Hc1,c2 A

where

Hc1,c2 : Coercive force, A/m

Qm1,m2 : Magnetic poles, A. m

A : Pole face area, m2

Assuming the distance, r is constant then from the above equations

F = 0 A2 Hc2 Hc2 / 4r2

According to the equilibrium of forces

F = 0

mg-Fm = 0

Fm = mg

where

Fm : Magnetic force, N

m : total mass of the wind turbine that need to be levitate,

g : gravitational acceleration ms-2

Therefore, the magnetic force must have equal forces to the weight of the wind

turbine so that it will levitate. Also, the type of magnet materials with known

characteristics can be determined using the above equation provided the weight of

model that needs to be levitated [9].

Some factors need to be assessed in choosing the permanent magnet selection that

would be best to implement the maglev portion of the design. Understanding the

characteristics of magnet materials and the different assortment of sizes, shapes

and materials is critical. There are four classes of commercialized magnets used

today which are based on their material composition each having their own

magnetic properties. The four different classes are Alnico, Ceramic, Samarium

Cobalt and Neodymium Iron Boron also known Nd- Fe-B. Nd-Fe-B is the most

recent addition to this commercial list of materials and at room temperature

exhibits the highest properties of all of the magnetic materials. It can be seen in

the B-H graph shown in Figure that Nd-Fe-B has a very attractive magnetic

characteristic which offers high flux density operation and the ability to resist

demagnetization. This attribute will be very important because the load that will

be levitated will be heavy and rotating a high speeds which will exhibit a large

downward force on the axis.

graph 3.1 - B-H Curve of Various Magnetic Materials [13]

The next factor that needs to be considered is the shape and size of the magnet

which is directly related to the placement of the magnets.

The permanent magnets that were chosen for this application were the

NX8CC-N42 magnets from K&J Magnetics. These are Nd-Fe-B ring shaped

permanent magnets that are nickel plated to strengthen and protect the magnet itself.

The dimensions for the magnets are reasonable with a outside diameter of 1.5 inches,

inside diameter of 0.75 inches and height of 0.75 inches.

3.2.2 WIND TURBINE

Considering the size and no. of blades 22" dia vortex type wind turbine is selected to

use in this project.

Technical Specifications:

Size : 24 dia. ( i.e. 600 mm)

Vortex Blades : Industrial grade Aluminum; 39 blades

Turbine Shaft : S.S. 304. 19mm dia

3.2.3 Flux Generator

Radial Flux Generator is selected for better voltage generation. 12 core

laminated stator is used, 25 X 6 mm twelve number neodymium magnets

are used as rotors. Coils are machine winded. 27 X 20 mm coil face is

winded.

CHAPTER - 04

4.1 ABOUT CATIA

CATIA (Computer Aided Three-dimensional Interactive Application) is a

multi-platform CAD/CAM/CAE commercial software suite developed by the French

company Dassault Systemes. Written in the C++ programming language, CATIA is

the cornerstone of the Dassault Systemes product lifecycle management software suite

[14].

Mechanical engineers equipped with 3D Modeling tools can gain insight into

key factors of quality and performance early in the product development phase.

Digital prototyping, combined with digital analysis and simulation, allows product

development teams to virtually create and analyze a mechanical product in its

operating environment.

3D Modeling solutions of CATIA Engineering Software enable the creation of

any type of 3D assemblies for a wide range of mechanical engineering processes.

They addresses the specific requirements of a wide range of processes and industries,

including cast and forged parts, plastic injection and other molding operations,

composites part design and manufacturing, machined and sheet metal parts design and

advanced welding and fastening operations. Engineers can rely on CATIA 3D

Modeling tools to define a complete mechanical product, including functional

tolerances, 3D annotations as well as kinematics. Predefined processes in CATIA

empower engineers to deliver greatly improved productivity, not only in completing

the mechanical design more quickly, but also in greatly reducing the time to perform

3D Modeling changes.

Scope of application

Commonly referred to as a 3D Product Lifecycle Management software suite, CATIA

supports multiple stages of product development (CAx), from conceptualization,

design (CAD), manufacturing (CAM), and engineering (CAE). CATIA facilitates

collaborative engineering across disciplines, including surfacing & shape design,

mechanical engineering, equipment and systems engineering.

CATIA provides a suite of surfacing, reverse engineering, and visualization solutions

to create, modify, and validate complex innovative shapes. From subdivision, styling,

and Class A surfaces to mechanical functional surfaces.

CATIA enables the creation of 3D parts, from 3D sketches, sheetmetal, composites,

molded, forged or tooling parts up to the definition of mechanical assemblies. It

provides tools to complete product definition, including functional tolerances, as well

as kinematics definition.

CATIA facilitates the design of electronic, electrical as well as distributed systems

such as fluid and HVAC systems, all the way to the production of documentation for

manufacturing.

Systems engineering

CATIA offers a solution to model complex and intelligent products through the

systems engineering approach. It covers the requirements definition, the systems

architecture, the behavior modeling and the virtual product or embedded software

generation. CATIA can be customized via application programming interfaces (API).

CATIA V5 & V6 can be adapted using Visual Basic and C++ programming

languages via CAA (Component Application Architecture); a component object

model (COM)-like interface.

Industries

CATIA can be applied to a wide variety of industries, from aerospace and defense,

automotive, and industrial equipment, to high tech, shipbuilding, consumer goods,

plant design, consumer packaged goods, life sciences, architecture and construction,

process power and petroleum, and services. Many automotive companies use CATIA

for car structures, door beams, IP supports, bumper beams, roof rails, side rails, body

components because CATIA is very good in surface creation and Computer

representation of surfaces. Bombardier Transportation, Canada is using this software

to design its entire fleet of Train engines and coaches.

4.2 DESIGN OF COMPONENTS IN CATIA V5R20

The process of designing a wind turbine involves the conceptual assembling of a large

number of mechanical and electrical components into a machine which can convert

the varying power in the wind into a useful form. This process is subject to a number

of constraints, but the fundamental ones involve the potential economic viability of

the design. Ideally, the wind turbine should be able to produce power at a cost lower

than its competitors, which are typically petroleum derived fuels, natural gas, nuclear

power, or other renewables. At the present state of the technology, this is often a

difficult requirement, so sometimes incentives are provided by governments to make

up the difference. Even in this case, it is a fundamental design goal to keep the cost of

energy lower than it would be from a turbine of a different design [5].

4.2.1 DESIGN OF MAGNETS

fig 4.1 : Drafting Sheet - Levitation Magnets

fig 4.2 : Catia - Product Design - Levitation Magnets

Specifications

Type : Neodymium Thickness : 6mm

Internal Diameter : 23mm External Diameter : 72mm

4.2.2 DESIGN OF WIND TURBINE BLADES

fig 4.3 : Drafting Sheet - Turbine Blade

fig 4.4 : Catia - Product Design - Turbine Blade

Specifications

Type : Vortex type turbine blade

Height : 35mm

Width : 4mm

Thickness : 0.5 mm

The wind turbine control problem has at least three important requirements:

1. setting upper bounds on and limiting the torque and power experienced by the

drive train, principally the low-speed shaft.

2. minimizing the fatigue life extraction from the rotor drive train and other

structural components due to changes in wind direction, speed (including gusts),

and turbulence, as well as start-stop cycles of the wind turbine.

3. maximizing the energy production.

Loads considerations in design: Loads on the blades of vertical axis wind

turbines are cyclic due to rotation of the blade upwind and downwind. This

constantly changes the orientation of the blade relative to the wind, leading to

changes in angle of attack and aerodynamic loads. As this effect is related to the

rotation of the rotor, the frequencies contained in the load signal occur at integer

multiples of the rotational frequency. Atmospheric turbulence adds stochastic

components to cyclic loads, introducing energy between each per revolution

cyclic frequency. Experimental stress measurements show the cyclic nature of the

response as well as the stochastic effect on the structure [5].

4.2.3 DESIGN OF WIND TURBINE SHAFT

fig 4.5 : Drafting Sheet - Turbine Shaft

fig 4.6 : Catia - Product Design - Turbine Shaft

Specifications

Type : Stepped Shaft

Length : 400mm

Turbine Supporting Shaft Diameter : 19mm Step dia : 6mm

4.2.4 DESIGN OF WIND TURBINE BASE

fig 4.7 : Drafting Sheet - Turbine Base

fig 4.8 : Catia - Product Design - Turbine Base

Base Diameter : 580mm

thickenss : 3mm

4.2.5 DESIGN MAGNET SLEEVE

fig 4.9 : Drafting Sheet - Magnet sleeve

fig 4.10 : Catia - Product Design - Magnet Sleeve

Specificatios :

Bore dia : 31mm

Bush dia : 72 mm

fig 4.11 : Turbine Blade hub assembly

CHAPTER - 05

5.1 FABRICATION TECHNIQUES

5.1.1 NEODYMIUM MAGNETS

The Neodymium metal element is initially separated from refined Rare Earth

oxides in an electrolytic furnace. The "Rare Earth" elements are lanthanoids (also

called lanthanides) and the term arises from the uncommon oxide minerals used to

isolate the elements. Although the term "Rare Earth" is used, it does not mean that the

chemical elements are scarce. The Rare Earth elements are abundant e.g. Neodymium

element is more common than gold. The Neodymium, Iron and Boron are measured

out and put in a vacuum induction furnace to form an alloy. Other elements are also

added, as required for specific grades e.g. Cobalt, Copper, Gadolinium and

Dysprosium (e.g. to assist with corrosion resistance). The mixture is melted due to the

high frequency heating and melting the mixture [13].

In simplified terms, the "Neo" alloy is like a cake mixture with each factory

having its own recipe for each grade. The resultant melted alloy is then cooled to form

ingots of alloy. The alloy ingots are then broken down by hydrogen decrepitation

(HD) or hydrogenation disproportionate desorption and recombination (HDDR) and

jet milled down in a nitrogen and argon atmosphere to a micron sized powder (about 3

microns or less in size). This Neodymium powder is then fed into a hopper to allow

the pressing of magnets to occur.

There are three main methods of pressing the powder axial and transverse

pressing. Die pressing requires tooling to make a cavity that is slightly larger than the

required shape (because sintering causes shrinkage of the magnet). The Neodymium

powder enters the die cavity from the hopper and is then compacted in the presence of

an externally applied magnetic field. The external field is either applied parallel to the

compacting force (this axial pressing is not so common) or perpendicular to the

direction of compaction (this is called transverse pressing). Transverse pressing gives

higher magnetic properties for the NdFeB.

A third method of pressing is isostatic pressing. The NdFeB powder is put into

a rubber mould and is put into a large fluid filled container which then has the

pressure of the fluid increased. Again an external magnetizing field is present but the

NdFeB powder is compacted from all sides. Isostatic pressing gives the best possible

magnetic performance for Neodymium Iron Boron. The methods employed vary

depending on the grade of "Neo" required and are decided by the manufacturer.

The external magnetizing field is created by a solenoid coil set either side of

the compacting powder. The magnetic domains of the NdFeB powder align with the

magnetizing field that is applied the more homogenous the applied field, the more

homogenous the magnetic performance of the Neodymium magnet. As the

Neodymium powder is pressed by the die, the direction of magnetization is locked in

place the Neodymium magnet has been given a preferred direction of magnetization

and is called anisotropic (if no external field were applied it would be possible to

magnetise the magnet in any direction, which is called isotropic). Once the final

dimensions for the magnet has been met by machining, the Neodymium magnet is

given a protective coating. This is usually a Ni-Cu-Ni coating.

The magnet must be cleaned to remove any swarf/powder from machining. It

is then dried thoroughly before being plated. It is imperative that the drying is

thorough otherwise water is locked into the plated Neodymium magnet and the

magnet will corrode from the inside out.

The following were the fabrication techniques involved :

Lathe

When a work piece is fixed between the headstock and the tail-stock, it is said

to be "between centers". When a work piece is supported at both ends, it is more

stable, and more force may be applied to the work piece, via tools, at a right angle to

the axis of rotation, without fear that the work piece may break loose.

When a work piece is fixed only to the spindle at the headstock end, the work

is said to be "face work". When a work piece is supported in this manner, less force

may be applied to the work piece, via tools, at a right angle to the axis of rotation, lest

the work piece rip free. Thus, most work must be done axially, towards the headstock,

or at right angles, but gently.

Riveting

A rivet is a permanent mechanical fastener. Before being installed a rivet

consists of a smooth cylindrical shaft with a head on one end. The end opposite the

head is called the buck-tail. On installation the rivet is placed in a punched or pre-

drilled hole, and the tail is upset, or bucked (i.e. deformed), so that it expands to about

1.5 times the original shaft diameter, holding the rivet in place. To distinguish

between the two ends of the rivet, the original head is called the factory head and the

deformed end is called the shop head or buck-tail.

Because there is effectively a head on each end of an installed rivet, it can

support tension loads (loads parallel to the axis of the shaft); however, it is much more

capable of supporting shear loads (loads perpendicular to the axis of the shaft). Bolts

and screws are better suited for tension applications.

Arc welding

Arc welding uses a welding power supply to create an electric arc between an

electrode and the base material to melt the metals at the welding point. They can use

either direct (DC) or alternating (AC) current, and consumable or non-consumable

electrodes. The welding region is sometimes protected by some type of inert or semi-

inert gas, known as a shielding gas, and/or an evaporating filler material.

Drilling

Drilled holes are characterized by their sharp edge on the entrance side and the

presence of burrs on the exit side (unless they have been removed). Also, the inside of

the hole usually has helical feed marks.

Drilling may affect the mechanical properties of the workpiece by creating

low residual stresses around the hole opening and a very thin layer of highly stressed

and disturbed material on the newly formed surface. This causes the workpiece to

become more susceptible to corrosion at the stressed surface.

When possible drilled holes should be located perpendicular to the workpiece

surface. This minimizes the drill bit's tendency to "walk", that is, to be deflected,

which causes the hole to be misplaced. The higher the length-to-diameter ratio of the

drill bit, the higher the tendency to walk.

5.2 WIND TURBINE BLADES ASSEMBLY

5.2 PROTOTYPE COMPONENTS

Turbine Base & Shaft

weight : 7kg

Base Material : Steel

Shaft Material : SS 304 (non magnetizing)

FIG 5.1 : Turbine Base with fixed stepped shaft

Magnet Sleeve

Weight : 350gms

Material : Aluminium

fig 5.2 : Magnet Sleeve to fix magnet to shaft

Wind Turbine blade hub

fig 5.3 : Blade hub

Vortex Blades :- Industrial grade Aluminum; 39 vens of 0.5 mm thick ; size : 22inch

Rotor

made of 12 L - Joints as in Dodecagon

twelve 25 X 6 mm neodymium magnets to create flux

8mm core gap is allowed

` fig 5.4 : Rotor

fig 5.5 : Rotor integrated to Turbine head & setup on rigid base

fig 5.6 : Magnetic Levitation in progress

fig 5.7 : Stator in alignment to rotor

5.4 ACESORIES USED

5.4.1 Multimeter

A multimeter or a multitester, also known

as a VOM (Volt-Ohm meter), is an electronic

measuring instrument that combines several

measurement functions in one unit. A typical

multimeter would include basic features such

as the ability to measure voltage, current, and

resistance. A multimeter can be a hand-held

device useful for basic fault finding and field

service work, or a bench instrument which

can measure to a very high degree of

accuracy.

fig 5.8 : Multimeter M830B

5.4.2 Vernier caliper

The vernier, dial, and digital calipers give a direct reading of the distance

measured with high accuracy and precision. These calipers comprise a calibrated

scale with a fixed jaw, and another jaw, with a pointer, that slides along the scale.

fig 5.9 : YAMAYO Vernier Callipers

5.4.3 Spirit level

A spirit level or bubble level is an instrument

designed to indicate whether a surface is horizontal

(level) or vertical (plumb).

Alcohols such as ethanol are often used rather

than water for a variety of reasons. Alcohols generally

have very low viscosity and surface tension, which

allows the bubble to travel the tube quickly and settle

accurately with minimal interference with the glass

surface.

fig 5.10 : Spirit Level

CHAPTER - 06

6.1 TEST PROCEDURE

Test 1: The starting wind speed of wind turbine model

1. The model is assembled to be the maglev wind turbine

2. A fan is placed in the direction parallel to the maglev wind turbine model.

3. The fan is switched on and the wind produced is directed to the model.

4. The model is replaced by anemometer and the fan is switched on again. The

wind speed is recorded

5. The test is repeated by using conventional wind turbine model.

Test 2: The rotational speed of wind turbine model at constant wind speed

1. The steps 1 until 4 in test 1 are repeated.

2. The reading of rotational speed of model is recoded after 1min for 5 times.

3. The test is repeated by using conventional wind turbine model. The distance

between the maglevand conventional wind turbine model with the fan is made

sure to be the same.

Test 3: The time taken by wind turbine model to stop rotation

1. The steps 1 until 3 in test 1 are repeated.

2. The fan is then switch off after 5min and a card bock is placed in front of it.

3. The time at which the model to stop its rotation completely is recorded.

4. Steps 2 and 3 are repeated for two times.5. The test is repeated by using

conventional wind turbine model.

6.2.1 TEST RESULTS

Table 6.1 Test 1: The starting wind speed of wind turbine model

Wind Turbine

Model Starting Wind Speed Average (m/s)

Maglev 1.9 1.5 1.4 1.60

Conventional 4.2 4.5 4.6 4.59

Table 6.2 Test 2: The rotational speed of wind turbine model at constant wind speed

Wind Turbine

Model

Rotational Speed (RPM) Average (rpm)

Maglev 66 66 60 61 63 63.2

Conventional 29 29 23 27 23 26.2

Table 6.3 Test 3: The time taken by wind turbine model to stop rotation

Wind Turbine

Model

Time Taken (s) Average )s)

Maglev 14.1 15.7 13.7 14.5

Conventional 1.6 1.5 1.4 1.5

6.2.2 DISCUSSION

From the test 1, the wind turbine model with magnetic levitation starts to rotate at

lower wind speed than that of conventional wind turbine..Most of the existing wind

turbine requires high starting wind speed to operate.

Maglev wind turbine is able to start to rotate at lower wind speed compare with

conventional wind turbine. This can be explained in terms of friction force. In general,

there are two friction force exist in an operating wind turbine. Since the turbine blades

are attached to the shaft by using ball bearing, a friction force is produced between

them. Also, there is another friction forces exist between the turbine blades and the

fixed base. In wind turbine with magnetic levitation, the latter one can be eliminate

because the turbine blades are lift up by magnetic force. This wind turbine need only

overcome the moment inertia and friction forces between the shaft and bearing before

it start to rotate. Instead, the conventional wind turbine needs to overcome moment

inertia and both the friction forces, and thus needs higher wind speed which results in

more energy to start to rotate. In addition, magnetic levitation wind turbine requires

less maintenance compare with the conventional wind turbine. This is because the

disadvantage of using bearing is it will wear off as the time goes on. Therefore, the

bearing needs to be replaced after some time so that the wind turbine is operating

efficiently.

From test 2, the maglev wind turbine model has a higher rotating speed than the

conventional wind turbine under constant wind speed. This result can be explained in

terms of energy conversion. According to the law of energy conservation, part of

kinetic energy in flowing wind is converted into kinetic energy due to rotating turbine

blades, and then produces electric energy. However, the arrangement of the

components of wind turbine limits this conversion and results in energy loss in terms

of heat and sound. Therefore, the conventional wind turbine experiences much energy

loss in term of heat and sound. More kinetic energy is needed to overcome the friction

forces exist between the bearings attached to the turbine blades and bottom. This

make the rotational speed of conventional wind turbine become lower than the maglev

one. Higher rotational speed means higher kinetic energy of rotating turbine blades

and hence more electric energy can be generated by maglev wind turbine.

From test 3, the maglev wind turbine model take a longer time to stop its rotation

completely compare to conventional one. This test is carried out under the same wind

speed. The wind may come to a lower speed and even stop at every instant of time.

Higher stopping time is desired because the wind turbine can still rotate at lower

speed in longer time when the speed of flowing wind decrease. And when the wind

speed increases, the wind turbine immediately rotate faster without achieve the

starting wind speed (if wind turbine stop in few seconds).

CONCLUSION

Over all, the magnetically levitated vertical axis wind turbine was a success. The

rotors that were designed harnessed enough air to rotate the stator at low and high

wind speeds while keeping the center of mass closer to the base yielding stability.

The wind turbine rotors and stator levitated properly using permanent magnets which

allowed for a smooth rotation with negligible friction. The Vertical Axis Wind

Turbine (VAWT) with magnetic levitation performed better than the conventional

wind turbine.

Tests results VAWT model has lower starting wind speed compare to

conventional one. The rotational speed of maglev VAWT is higher. The time taken

for the maglev wind turbine to stop rotating is longer than that of conventional.

Therefore, the Maglev wind turbine is more suitable for power generation application.

The home for the magnetically levitated vertical axis wind turbine would be in

residential areas. Here it can be mounted to a roof and be very efficient and able to

extract free clean energy thus experiencing a reduction in their utility cost and also

contribute to the Green Energy awareness that is increasingly gaining popularity.

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RFI - Vertical Axis Wind Turbine 200 Mega Watt Off Shore Wind Farm

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WIT Press

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[14] http://www.3ds.com/products/catia/