Project Report

Power generation using speed breakers

CHAPTER - 1

INTRODUCTION

In the present scenario power becomes the major need for human life .The

availability and its per capita consumptions is regarded as the index of national

standard of living in the present day civilization. Energy is an important input

in all the sectors of any countries economy. Energy crisis is due to two reasons,

firstly the population of the world has been increased rapidly and secondly

standard of living of human beings has increased.

India is the country, which majorly suffers with lack of sufficient power

generation. The capital energy consumption of U.S.A. is about 8000 K.W.H.,

where as per INDIA is only 150 K.W.H. U.S.A. with 7% of world population

consumes 32% of total power generation where as INDIA as developing

country with 20% of world population consumes only 1% of total energy

consumed in the world.The availability of regular conventional fossil fuels will

be the main sources for power generation, but there is a fear that they will get

exhausted eventually by the next few decades. Therefore, we have to

investigate some approximate, alternative, new sources for the power

generation, which is not depleted by the very few years.

Another major problem, which is becoming the exiting topic for today is the

pollution. It suffers all the living organisms of all kinds as on the land, in aqua

and in air. Power stations and automobiles are the major pollution producing

places. Therefore, we have to investigate other types of renewable sources,

which produce electricity without using any commercial fossil fuels, which is

not producing any harmful products.

Fuel deposit will deplete soon by the end of 2020 .Fuel scarcity will be

maximum. Country like India may not have the chance to use petroleum

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products. Keeping this dangerous situation in mind we tried to make use of

non-pollutant natural resource of petrol.

There are already existing such systems using renewable energy such as solar,

wind), OTEC (ocean thermal energy conversions) etc…for power generation.

The latest technology which is used to generate the power by such renewable

energy is the” POWER HUMP”.

An energy crisis is great bottleneck (or price rise) in the supply of energy

resources to an economy. It usually refers to the shortage of oil and additionally

to electricity or other natural resources. An energy crisis may be referred to as

an oil crisis, petroleum crisis, energy shortage, electricity shortage electricity

crisis. A crisis can develop due to industrial actions like union organized strikes

and government embargoes. The cause may be ageing over-consumption,

infrastructure and sometimes bottlenecks at oil refineries and port facilities

restrict fuel supply.

This is our step to improve the situation of electricity with an innovative and

useful concept i.e. Generating Electricity from a Speed breaker. Electricity is

the form of energy. It is the flow of electrical Power. Electricity is a basic part

of nature and it is one of our most widely used forms of energy. We get

electricity, which is a secondary energy source, from the conversion of other

sources of energy, like coal, natural gas, oil, nuclear power and other natural

sources, which are called primary sources.

Many cities and towns were built alongside waterfalls that turned water wheels

to perform work. Before electricity generation began slightly over 100 years

ago, houses were lit with kerosene lamps, food was cooled in iceboxes, and

rooms were warmed by wood-burning or coal-burning stoves. Direct current

(DC) electricity had been used in arc lights for outdoor lighting. In the late-

1800s, Nikola Tesla pioneered the generation, transmission, and use of

alternating current (AC) electricity, which can be transmitted over much greater

distances than direct current. Tesla's inventions used electricity to bring indoor

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lighting to our homes and to power industrial machines. How is electricity

generated? Electricity generation was first developed in the 1800's using

Faraday’s dynamo generator. Almost 200 years later we are still using the same

basic principles to generate electricity, only on a much larger scale.

This project is about GENERATION OF ELECTRICITY BY USING SPEED

BREAKERS. This is one of the best suitable solutions to the electricity crisis.

This project will work on the principle of “MECHANICAL ENERGY TO

ELECTRICAL ENERGY CONVERSION”.

In this project a mechanism is used to generate power by converting the

mechanical energy generated by a vehicle going up on a speed breaker into

electrical energy. Producing electricity from a speed breaker is a new concept

that is undergoing research. The number of vehicles on road is increasing

rapidly and if we convert some of the kinetic energy of these vehicles into the

rotational motion of roller then we can produce considerable amount of

electricity, this is the main concept of this project.

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1.1BASIC MECHANISMS:

This project is done by using three different mechanisms. They are:

1. Roller mechanism

2. Rack- Pinion mechanism

3. Crank-shaft mechanism

1.1.1Roller Mechanism:

This mechanism comprises a support element and a drive

sprocket which is rotatable, mounted on the support element for transmitting

rotational movement to a blind supporting member and a manually-movable

elongate flexible drive element which includes a plurality of interlinked tooth-

engaging elements, and the drive sprocket including a plurality of tooth-

engaging elements of the flexible drive element.

Fig 1.1.1(a) Roller mechanism setup

Roller mechanism has some different disadvantages. Maintenance will be very

difficult and might cause collision.

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The rotor (rotating shaft) is directly connected to the prime mover and rotates

as the prime mover turns. The rotor contains a magnet that, when turned,

produces a moving or rotating magnetic field. The rotor is surrounded by a

stationary casing called the stator, which contains the wound copper coils or

windings. When the moving magnetic field passes by these windings,

electricity is produced in them.

In roller blind mechanism a radial extent of the teeth of the drive sprocket is

equal to or greater than a maximum dimension of the tooth-engaging elements

of the flexible drive element. And the radial extent is equal to or greater than

twice the maximum dimension of the tooth-engaging elements of the flexible

drive element. The teeth of the drive sprocket flex in a circumferential direction

of the sprocket.

Fig 1.1.1(b) Roller mechanism

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1.1.2Rack And Pinion Mechanism:

Rack and pinion gears normally change rotary motion into linear motion, but

sometimes we use them to change linear motion into rotary motion. They

transform a rotary movement (that of the pinion) into a linear movement (that

of the rack) or vice versa.

The Kinetic energy of moving vehicles can be converted into mechanical

energy of the shaft through rack and pinion mechanism. This shaft is connected

to the electric dynamo and it produces electrical energy proportional to traffic

density. This generated power can be regulated by using zenor diode for

continuous supply .All this mechanism can be housed under the dome like

speed breaker, which is called ‘hump’.

The generated power can be used for general purpose like streetlights, traffic

signals. The electrical output can be improved by arranging these power humps

in series and this generated power can be amplified and stored by using

different electric devices. The maintenance cost of hump is almost nullified. By

adopting this arrangement, we can satisfy the future demands to some extent.

Fig 1.1.2 Rack and pinion mechanism

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1.1.3 Crank Shaft Mechanism:

A crank is an arm attached at right angles to a rotating shaft by

which reciprocating motion is imparted to or received from the shaft. It is used

to convert circular motion into reciprocating motion, or sometimes

reciprocating motion into circular. The arm may be a bent portion of the shaft,

or a separate arm attached to it. Attached to the end of the crank by a pivot is a

rod, usually called a connecting rod. The end of the rod attached to the crank

moves in a circular motion, while the other end is usually constrained to move

in a linear sliding motion, in and out.

The crankshaft is a mechanism that transforms rotary movement into linear

movement, or vice versa. For example, the motion of the pistons in the engine

of a car is linear (they go up and down). But the motion of the wheels has to be

rotary. So, engineers put a crankshaft between the engine and the transmission

to the wheels. The pistons of the engine move the crankshaft and the movement

becomes rotary. Then the rotary movement goes past the clutch and the gear

box, all the way to the wheels.

Fig 1.1.3 Crank shaft mechanism

7

http://en.wikipedia.org/wiki/Linear_motion

http://en.wikipedia.org/wiki/Connecting_rod

http://en.wikipedia.org/wiki/Circular_motion

http://en.wikipedia.org/wiki/Reciprocating_motion


In this project we selected Rack and Pinion mechanism because Rack-

Pinion assembly gives good mounting convenience and Maximum gear losses

are up to 3 to 5%,Efficiency– 95%. In crankshaft mechanism , Crank-shafts are

required to be mounted on bearings which creates balancing problem leading to

mechanical vibrations which in turn damage the bearings. In roller mechanism

Maintenance will be very difficult and Might cause collision between rollers

and gears

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CHAPTER - 2

COMPONENTS AND DESCRIPTION

The block diagram of the speed breaker using power generation is shown in

figure. The main components of this project are,

2.1 Speed Brake arrangement

2.2 Rack and pinion arrangement

2.3 Sprocket and chain Drive

2.4 Fly wheel

2.5 D.C generator

2.6 Battery

2.7 Inverter and

2.8 Light Arrangement

2.1 SPEED BRAKE ARRANGEMENT:

This is made up of mild steel. The complete set up is fixed in a box. The two L-

angles frame is fixed in the above two ends of the box. Bellow this L-angle

window, the actual speed brake arrangement is constructed. This L-angle

window pushes the speed brake when the time of vehicle moving on these

arrangement.BLOCK DIAGRAM

Fig 2.1 Speed breaker arrangement

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SPEED BRAKEARRANGEMENT

DC GENERATOR BATTERY LIGHT

LOADINVERTER

RACK & PINION AND CHAIN SPROCKET

ARRANGEMENT


2.2RACK AND PINION ARRANGEMENT:

The block is the important part of the unit as it houses the rack and pinion. This

rack and pinion attachment gives the rotary motion to the chain sprocket. This

block converts linear motion into rotary motion.

Rack and pinion gear system is used to transmit rotary motion into linear

motion. The rack is a portion of a gear having an infinite pitch diameter and the

line of action is tangent to the pinion.

Pinion:

This is a gear wheel which is provided to get mesh with rack to convert the

linear motion into rotary motion. They are made up of Cast iron. Type of gear

is spur gear.

A gear is a rotating machine part having cut teeth, or cogs, which mesh with

another toothed part in order to transmit torque. Two or more gears working in

tandem are called a transmission and can produce a mechanical

advantage through a gear ratio and thus may be considered a simple machine.

Spur gears are the most common type of gears. They have straight teeth, and

are mounted on parallel shafts. Tooth type is primarily rolling with sliding

during engagement and disengagement. some noise is normal. but it becomes

objectionable at high speeds.

Rack:

Rack teeth are cut horizontally about the required length. This is made up of

Cast iron. Rack is having infinite pitch circle diameter.

10

http://en.wikipedia.org/wiki/Simple_machine

http://en.wikipedia.org/wiki/Gear_ratio

http://en.wikipedia.org/wiki/Mechanical_advantage

http://en.wikipedia.org/wiki/Mechanical_advantage

http://en.wikipedia.org/wiki/Transmission_(mechanics)

http://en.wikipedia.org/wiki/Torque

http://en.wikipedia.org/wiki/Machine_(mechanical)

http://en.wikipedia.org/wiki/Rotating


2.3 BEARINGS:

A bearing is any of various machine elements that constrain the relative motion

between two or more parts to only the desired type of motion. This is typically

to allow and promote freerotation around a fixed axis or free linear movement;

it may also be to prevent any motion, such as by controlling

the vectors of normal forces. Bearings may be classified broadly according to

the motions they allow and according to their principle of operation, as well as

by the directions of applied loads they can handle.

In this project we used ball bearings. A ball bearing is a type of rolling-element

bearing that uses balls to maintain the separation between the bearing races.

The purpose of a ball bearing is to reduce rotational friction and

support radial and axial loads. It achieves this by using at least two races to

contain the balls and transmit the loads through the balls. In most applications,

one race is stationary and the other is attached to the rotating assembly (e.g., a

hub or shaft). As one of the bearing races rotates it causes the balls to rotate as

well. Because the balls are rolling they have a much lower coefficient of

friction than if two flat surfaces were rotating on each other.

Ball bearings tend to have lower load capacity for their size than other kinds of

rolling-element bearings due to the smaller contact area between the balls and

races. However, they can tolerate some misalignment of the inner and outer

races.

The calculated life for a bearing is based on the load it carries and its operating

speed. The industry standard usable bearing lifespan is inversely proportional

to the bearing load cubed.

If a bearing is not rotating, maximum load is determined by force that causes

non-elastic deformation of balls. If the balls are flattened, the bearing does not

11

http://en.wikipedia.org/wiki/Structural_load

http://en.wikipedia.org/wiki/Coefficient_of_friction

http://en.wikipedia.org/wiki/Coefficient_of_friction

http://en.wikipedia.org/wiki/Axis_of_rotation

http://en.wikipedia.org/wiki/Radius

http://en.wikipedia.org/wiki/Race_(bearing)

http://en.wikipedia.org/wiki/Bearing_(mechanical)

http://en.wikipedia.org/wiki/Ball_(bearing)

http://en.wikipedia.org/wiki/Rolling-element_bearing

http://en.wikipedia.org/wiki/Rolling-element_bearing

http://en.wikipedia.org/wiki/Normal_force

http://en.wikipedia.org/wiki/Vector

http://en.wikipedia.org/wiki/Line_(geometry)

http://en.wikipedia.org/wiki/Rotation_around_a_fixed_axis

http://en.wikipedia.org/wiki/Moving_parts

http://en.wikipedia.org/wiki/Machine_element


rotate. Maximum load for not or very slowly rotating bearings is called "static"

maximum load. If that same bearing is rotating, that deformation tends to knead

the ball into roughly a ball shape, so the bearing can still rotate, but if this

continues for a long time, the ball fails due to metal fatigue. Maximum load for

rotating bearing is called "dynamic" maximum load, and is roughly two or

three times as high as static maximum load.

If a bearing is rotating, but experiences heavy load that lasts shorter than one

revolution, static maximum load must be used in computations, since the

bearing does not rotate during the maximum load.

Fig 2.3 Ball bearing

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2.4 SPROCKET AND CHAIN DRIVE:

This is a cycle chain sprocket. The chain sprocket is coupled with another

generator shaft. The chain converts rotational power to pulling power, or

pulling power to rotational power, by engaging with the sprocket.

The sprocket looks like a gear but differs in three important ways:

1. Sprockets have many engaging teeth; gears usually have only one or two.

2. The teeth of a gear touch and slip against each other; there is basically no

slippage in a sprocket.

3. The shape of the teeth is different in gears and sprockets.

Fig 2.4 (a) Types of Sprockets

Engagement with Sprockets:

Although chains are sometimes pushed and pulled at either end by cylinders,

chains are usually driven by wrapping them on sprockets. In the following

section, we explain the relation between sprockets and chains when power is

transmitted by sprockets.

Back tension:

The relationship between flat belts and pulleys is explained below. Figure

2.4(b) shows a rendition of a flat belt drive. The circle at the top is a pulley, and

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the belt hangs down from each side. When the pulley is fixed and the left side

of the belt is loaded with tension (T0), the force needed to pull the belt down to

the right side will be:

T1 = T0 3 eµu

For example, T0 = 100 N: the coefficient of friction between the belt and

pulley, µ = 0.3;

the wrap angle u = ¼ (180).

T1 = T0 3 2.566 = 256.6 N

In brief, when you use a flat belt in this situation, you can get 256.6 N of drive

power only when there is 100 N of back tension.

For elements without teeth such as flat belts or ropes, the way to get more drive

power is to increase the coefficient of friction or wrapping angle. If a

substance, like grease or oil, which decreases the coefficient of friction, gets

onto the contact surface, the belt cannot deliver the required tension.

In the chain's case, sprocket teeth hold the chain roller. If the sprocket tooth

configuration is square, as in Figure 2.4(c), the direction of the tooth's reactive

force is opposite the chain's tension, and only one tooth will receive all the

chain's tension. Therefore, the chain will work without back tension.

Fig. 2.4(b) Flat Belt Drive

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Fig. 2.4 (c) Simplified Roller/Tooth Forces

But actually, sprocket teeth need some inclination so that the teeth can engage

and slip off of the roller. The balances of forces that exist around the roller are

shown in Figure 2.4(d) , and it is easy to calculate the required back tension.

For example, assume a coefficient of friction µ = 0, and you can calculate the

back tension (Tk) that is needed at sprocket tooth number k with this formula:

Tk = T0 3 sin ø (k-1) sin(ø + 2b)

Where:

Tk = back tension at tooth k

T0 = chain tension

ø = sprocket minimum pressure angle 17 64/N(š)

N = number of teeth

2b = sprocket tooth angle (360/N)

k = the number of engaged teeth (angle of wrap 3 N/360); round down to

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Fig. 2.4 (d) The Balance of Forces Around the Roller


the nearest whole number to be safe

By this formula, if the chain is wrapped halfway around the sprocket, the back

tension at sprocket tooth number six is only 0.96 N. This is 1 percent of the

amount of a flat belt. Using chains and sprockets, the required back tension is

much lower than a flat belt.

Comparison between chains - sprockets and toothed-belt back tension:

Although in toothed belts the allowable tension can differ with the number of

pulley teeth and the revolutions per minute (rpm), the general recommendation

is to use 1/3.5 of the allowable tension as the back tension (F). This is shown in

below Figure 2.8. Therefore, our 257 N force will require 257/3.5 = 73 N of

back tension.

Both toothed belts and chains engage by means of teeth, but chain's back

tension is only 1/75 that of toothed belts.

Figure 2.4(e) Back Tension on a Toothed Belt

Chain wear and jumping sprocket teeth:

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The key factor causing chain to jump sprocket teeth is chain wear elongation

Because of wear elongation, the chain creeps up on the sprocket teeth until it

starts jumping sprocket teeth and can no longer engage with the sprocket.

Figure 2.4(f) shows sprocket tooth shape and positions of engagement. Figure

2.4(g) shows the engagement of a sprocket with an elongated chain.

In Figure 2.4(f) there are three sections on the sprocket tooth face:

a: Bottom curve of tooth, where the roller falls into place;

b: Working curve, where the roller and the sprocket are working together;

c: Where the tooth can guide the roller but can't transmit tension. If the roller,

which should transmit tension, only engages with C, it causes jumped

sprocket teeth.

The chain's wear elongation limit varies according to the number of sprocket

teeth and their shape, as shown in Figure 2.4(h). Upon calculation, we see that

sprockets with large numbers of teeth are very limited in stretch percentage.

Smaller sprockets are limited by other harmful effects, such as high vibration

and decreasing strength; therefore, in the case of less than 60 teeth, the stretch

limit ratio is limited to 1.5 percent (in transmission chain).

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Fig.2.4(f) Sprocket Tooth Shape and Positions of Engagement


Fig. 2.4(g) The Engagement Between a Sprocket andan Elongated Chain

In conveyor chains, in which the number of working teeth in sprockets is less

than transmission chains, the stretch ratio is limited to 2 percent. Large pitch

conveyor chains use a straight line in place of curve B in the sprocket tooth

face.

A chain is a reliable machine component, which transmits power by means of

tensile forces, and is used primarily for power transmission and conveyance

systems. The function and uses of chain are similar to a belt. There are many

kinds of chain. It is convenient to sort types of chain by either material of

composition or method of construction.

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Fig.2.4(h) Elongation Versus the Number of Sprocket Teeth


We can sort chains into five types:

Cast iron chain.

Cast steel chain.

Forged chain.

Steel chain.

Plastic chain.

Demand for the first three chain types is now decreasing; they are only used in

some special situations. For example, cast iron chain is part of water-treatment

equipment; forged chain is used in overhead conveyors for automobile

factories. “steel chain," especially the type called "roller chain," which makes

up the largest share of chains being produced, and "plastic chain." For the most

part, we will refer to "roller chain" simply as "chain."

NOTE: Roller chain is a chain that has an inner plate, outer plate, pin, bushing,

and roller.

chains according to their uses, which can be broadly divided into six types:

1. Power transmission chain.

2. Small pitch conveyor chain.

3. Precision conveyor chain.

4. Top chain.

5. Free flow chain.

6. Large pitch conveyor chain.

The first one is used for power transmission; the other five are used for

conveyance. there are special features in the composition of precision conveyor

chain, top chain, and free flow chain.

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Basic Structure of Power Transmission Chain

A typical configuration for RS60-type chain is shown in Figure 2.4.2

Connecting link :

This is the ordinary type of connecting link. The pin and link plate are slip fit in

the connecting link for ease of assembly. This type of connecting link is 20

percent lower in fatigue strength than the chain itself. There are also some

special connecting links which have the same strength as the chain itself.

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Fig. (2.4.2.) The Basic Components of Transmission

Chain


Tap Fit Connecting Link In this link, the pin and the tap fit connecting link

plate are press fit. It has fatigue strength almost equal to that of the chain itself.

Offset Link

An offset link is used when

an odd number of chain links

is required. It is 35 percent

lower in fatigue strength than the chain itself. The pin and two plates are slip

fit. There is also a two-pitch offset link available that has fatigue strength as

great as the chain itself.

2.5 FLY WHEEL:

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Fig. 2.4.2 (b) Standard Connecting Link (top)and Tap Fit Connecting Link (bottom)

Fig. 2.4.2(c) Offset Link


A flywheel is a rotating mechanical device that is used to store rotational

energy. Flywheels have a significant moment of inertia, and thus resist

changes in rotational speed. The amount of energy stored in a flywheel is

proportional to the square of its rotational speed. Energy is transferred to a

flywheel by applying torque to it, thereby increasing its rotational speed, and

hence its stored energy. Conversely, a flywheel releases stored energy by

applying torque to a mechanical load, thereby decreasing its rotational speed.

Three common uses of a flywheel include:

They provide continuous energy when the energy source is discontinuous.

For example, flywheels are used in reciprocating engines because the

energy source, torque from the engine, is intermittent.

They deliver energy at rates beyond the ability of a continuous energy

source. This is achieved by collecting energy in the flywheel over time and

then releasing the energy quickly, at rates that exceed the abilities of the

energy source.

They control the orientation of a mechanical system. In such applications,

the angular momentum of a flywheel is purposely transferred to a load

when energy is transferred to or from the flywheel.

Flywheels are typically made of steel and rotate on conventional bearings;

these are generally limited to a revolution rate of a few thousand RPM. A

rotating flywheel responds to any momentum that tends to change the direction

of its axis of rotation by a resulting precession rotation.

Fly wheel is used to increase the rpm of the system. The generator is coupled

with this shaft, so that increase the RPM of the generator.

2.6 PERMANENT MAGNET D.C. GENERATOR

22

http://en.wikipedia.org/wiki/Reciprocating_engine

http://en.wikipedia.org/wiki/Torque

http://en.wikipedia.org/wiki/Rotational_speed

http://en.wikipedia.org/wiki/Moment_of_inertia

http://en.wikipedia.org/wiki/Rotational_energy

http://en.wikipedia.org/wiki/Rotational_energy


A generator is a device that converts mechanical energy to electrical energy. A

generator forces electric charge (usually carried by electrons) to flow through

an external electrical circuit.

Voltage Production

DC Circuits, that there are three conditions necessary to induce a voltage into a

conductor.

1. A magnetic field

2. A conductor

3. Relative motion between the two.

A DC generator provides these three conditions to produce a DC voltage output. Theory of Operation A basic DC generator has four basic parts:

(1) A magnetic field;

(2) A single conductor, or loop;

(3) A commutator; and

(4) Brushes

The magnetic field may be supplied by either a permanent magnet or an

electromagnet. For now, we will use a permanent magnet to describe a basic

DC generator.

Basic Operation of a DC Generator A single conductor, shaped in the form of a

loop, is positioned between the magnetic poles. As long as the loop is

stationary, the magnetic field has no effect (no relative motion). If we rotate

the loop, the loop cuts through the magnetic field, and an EMF (voltage) is

induced into the loop.

23

http://en.wikipedia.org/wiki/Electrical_circuit

http://en.wikipedia.org/wiki/Electron

http://en.wikipedia.org/wiki/Electric_charge

http://en.wikipedia.org/wiki/Electrical_energy

http://en.wikipedia.org/wiki/Mechanical_energy


Fig 2.6 Generator construction

When we have relative motion between a magnetic field and a conductor in

that magnetic field, and the direction of rotation is such that the conductor cuts

the lines of flux, an EMF is induced into the conductor. The magnitude of the

induced EMF depends on the field strength and the rate at which the flux lines

are cut.

The stronger the field or the more flux lines cut for a given period of time, the

larger the induced EMF.

Eg = KFN

where Eg = generated voltage

K = fixed constant

F = magnetic flux strength

N = speed in RPM

Direction of the induced current flow can be determined using the "left-

hand rule" for generators. This rule states that if you point the index finger of

your left hand in the direction of the magnetic field (from North to South) and

point the thumb in the direction of motion of the conductor.

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For example, the conductor closest to the N pole is traveling upward across the

field; therefore, the current flow is to the right, lower corner. Applying the

left-hand rule to both sides of the loop will show that current flows in a

counter-clockwise direction in the loop.

DC GENERATOR CONSTRUCTION

Output Voltage-vs-Load Current for Shunt-Wound DC Generator the shunt-

wound generator, running at a constant speed under varying load conditions,

has a much more stable voltage output than does a series-wound generator.

Some change in output voltage does take place. This change is caused by the

fact that, as the load current increases, the voltage drop (I R) across the

armature coil increases, causing output voltage to decrease.

As a result, the current through the field decreases, reducing the magnetic field

and causing voltage to decrease even more. If load current is much higher than

the design of the generator, the drop in output voltage is severe. For load

current within the design range of the generator, the drop in output voltage is

minimal.

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2.7BATTERY

Batteries seem to be the only technically and economically available storage

means. Since both the photo-voltaic system and batteries are high in capital

costs. It is necessary that the overall system be optimized with respect to

available energy and local demand pattern. To be economically attractive the

storage of electricity requires a battery with a particular combination of

properties:

(1) Low cost

(2) Long life

(3) High reliability

(4) High overall efficiency

(5) Low discharge

(6) Minimum maintenance

We use lead acid battery for storing the electrical energy for lighting the street

and so about the lead acid cells are explained below.

LEAD-ACID WET CELL:

Where high values of load current are necessary, the lead-acid cell is the type

most commonly used. The electrolyte is a dilute solution of sulfuric acid

(H₂SO₄). In the application of battery power to start the engine in an auto

mobile, for example, the load current to the starter motor is typically 200 to

400A. One cell has a nominal output of 2.1V, but lead-acid cells are often used

in a series combination of three for a 6-V battery and six for a 12-V battery.

The lead acid cell type is a secondary cell or storage cell, which can be

recharged. The charge and discharge cycle can be repeated many times to

restore the output voltage, as long as the cell is in good physical condition.

However, heat with excessive charge and discharge currents shortens the useful

life to about 3 to 5 years for an automobile battery. Of the different types of

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secondary cells, the lead-acid type has the highest output voltage, which allows

fewer cells for a specified battery voltage.

CONSTRUCTION:

Inside a lead-acid battery, the positive and negative electrodes consist of a

group of plates welded to a connecting strap. The plates are immersed in the

electrolyte, consisting of 8 parts of water to 3 parts of concentrated sulfuric

acid. Each plate is a grid or framework, made of a lead-antimony alloy.

Fig 2.7 Lead acid Battery

CHEMICAL ACTION:

Sulfuric acid is a combination of hydrogen and sulfate ions. When the cell

discharges, lead peroxide from the positive electrode combines with hydrogen

ions to form water and with sulfate ions to form lead sulfate. Combining lead

on the negative plate with sulfate ions also produces he sulfate.

Therefore, the net result of discharge is to produce more water, which dilutes

the electrolyte, and to form lead sulfate on the plates. As the discharge

continues, the sulfate fills the pores of the grids, retarding circulation of acid in

27


the active material. Lead sulfate is the powder often seen on the outside

terminals of old batteries. When the combination of weak electrolyte and

sulfating on the plate lowers the output of the battery, charging is necessary.

On charge, the external D.C. source reverses the current in the battery. The

reversed direction of ions flows in the electrolyte result in a reversal of the

chemical reactions. Now the lead sulfates on the positive plate reactive with

the water and sulfate ions to produce lead peroxide and sulfuric acid. This

action re-forms the positive plates and makes the electrolyte stronger by adding

sulfuric acid.

At the same time, charging enables the lead sulfate on the negative plate to

react with hydrogen ions; this also forms sulfuric acid while reforming lead on

the negative plate to react with hydrogen ions; this also forms currents can

restore the cell to full output, with lead peroxide on the positive plates, spongy

lead on the negative plate, and the required concentration of sulfuric acid in the

electrolyte.

The chemical equation for the lead-acid cell is

Fig.2.7 (a) chemical action of battery

28


Charge

Pb + pbO₂ + 2H₂SO₄ 2pbSO₄ + 2H₂O

Discharge

On discharge, the pb and pbo₂ combine with the SO₄ ions at the left side of the

equation to form lead sulfate (pbSO₄) and water (H₂O) at the right side of the

equation. One battery consists of 6 cells, each have an output voltage of 2.1V,

which are connected in series to get an voltage of 12V and the same 12V

battery is connected in series, to get an 24 V battery. They are placed in the

water proof iron casing box.

CURRENT RATINGS:

Lead-acid batteries are generally rated in terms of how much discharge currents

they can supply for a specified period of time; the output voltage must be

maintained above a minimum level, which is 1.5 to 1.8V per cell. A common

rating is ampere-hours (A.h.) based on a specific discharge time, which is often

8h. Typical values for automobile batteries are 100 to 300 A.h.

As an example, a 200 A.h battery can supply a load current of 200/8 or 25A,

used on 8h discharge. The battery can supply less current for a longer time or

more current for a shorter time. Automobile batteries may be rated for “cold

cranking power”, which is related to the job of starting the engine. A typical

rating is 450A for 30s at a temperature of 0 degree F.

Note that the ampere-hour unit specifies coulombs of charge. For instance, 200

A.h. corresponds to 200A*3600s (1h=3600s). the equals 720,000 A.S, or

coulombs. One ampere-second is equal to one coulomb. Then the charge

equals 720,000 or 7.2*10^5ºC. To put this much charge back into the battery

would require 20 hours with a charging current of 10A.

29


The ratings for lead-acid batteries are given for a temperature range of 77 to

80ºF. Higher temperature increase the chemical reaction, but operation above

110ºF shortens the battery life.

Low temperatures reduce the current capacity and voltage output. The ampere-

hour capacity is reduced approximately 0.75% for each decreases of 1º F below

normal temperature rating. At 0ºF the available output is only 60 % of the

ampere-hour battery rating.

In cold weather, therefore, it is very important to have an automobile battery

unto full charge. In addition, the electrolyte freezes more easily when diluted

by water in the discharged condition.

An external D.C. voltage source is necessary to produce current in one

direction. Also, the charging voltage must be more than the battery e.m.f.

Approximately 2.5 per cell are enough to over the cell e.m.f. so that the

charging voltage can produce current opposite to the direction of discharge

current.

The reversal of current is obtained just by connecting the battery VB and

charging source VG with + to + and –to-, as shown in figure. The charging

current is reversed because the battery effectively becomes a load resistance for

VG when it higher than VB. In this example, the net voltage available to

produce charging currents is 15-12=3V.

A commercial charger for automobile batteries is essentially a D.C. power

supply, rectifying input from the AC power line to provide D.C. output for

charging batteries. Float charging refers to a method in which the charger and

the battery are always connected to each other for supplying current to the load.

In figure the charger provides current for the load and the current necessary to

keep the battery fully charged. The battery here is an auxiliary source for D.C.

power.

30


It may be of interest to note that an automobile battery is in a floating-charge

circuit. The battery charger is an AC generator or alternator with rectifier

diodes, driver by a belt from the engine. When you start the car, the battery

supplies the cranking power. Once the engine is running, the alternator charges

he battery. It is not necessary for the car to be moving. A voltage regulator is

used in this system to maintain the output at approximately 13 to 15 V.

The constant voltage of 24V comes from the solar panel controlled by the

charge controller so for storing this energy we need a 24V battery so two 12V

battery are connected in series. It is a good idea to do an equalizing charge

when some cells show a variation of 0.05 specific gravity from each other.

This is a long steady overcharge, bringing the battery to a gassing or bubbling

state. Do not equalize sealed or gel type batteries. With proper care, lead-acid

batteries will have a long service life and work very well in almost any power

system. Unfortunately, with poor treatment lead-acid battery life will be very

short.

2.8INVERTER

31


The process of converting D.C. into A.C. is known as INVERSION. In other

words, we may define it as the reverse process of rectification. The device,

which performs this process, is known as an INVERTOR. Inversion is, by no

means, a recent process. In olden days gas-filled tubes and vacuum tubes were

used to develop inverters. Thyratron inverter is popularly used as a large

power device. Vacuum tube inverters were generally used for high-frequency

applications. Some of the main disadvantages of the tube as well as the

mercury pool type inverters are:

1. They are very costly

2. They are very big in size and heavy in weight

3. They have very poor efficiency

4. The voltage drop across these devices is very high

5. They are less accurate

6. They are very slow in response, etc.

The basic principle of an inverter can be explained with the help of a simple

circuit, as shown in figure. If switch S is connected alternately to position 1 and

2 at a rapid speed and if S is not kept closed to any of the two positions (1 and

2) for too long, and then an alternating voltage will appear across the primary

winding. This can be explained by the direction of the current flow in the

primary winding.

Although the voltage applied is D.C. in nature, the direction of current flow in

the primary winding when S is connected to position 1 is from top to bottom

whereas when S is connected at position 2, the current flows from bottom to

top. This change in the direction of current flow in the primary winding gives

rise to an alternating voltage in it. The frequencies of this alternating voltage

will depend on how rapidly the switch (S) positions are interchanged. This

alternating voltage in the primary winding will induce an alternating emf in the

secondary winding, which will act as the A.C. output.

32


With the development of semi-conductor devices, a lot of improvements to

took place in the design of inverter circuits. Transistor being a fast-switching

device was used as a switch for developing low and medium power inverters.

CIRCUIT DIAGRAM

2.9 FLUORESCENT TUBES

33


This type of lamp is a low-pressure mercury vapor discharge lamp.

Fluorescent lighting has a great advantage over other light source in many

applications. It is possible to achieve quite high lighting intensities without

excessive temperature rises. The efficiency of fluorescent lamp is about 40

lumens per watt, about three times the efficiency of an equivalent tungsten

lamp. The average life of a fluorescent lamp is about 4,000 working hours.

CONSTRUCTION:

The fluorescent tube consists of a glass tube and 0.6 meter, 1.2 meters and 1.5

meters in length. The inside surface of the tube is coated with a thin layer of

fluorescent material in the form of a powder. Various fluorescent materials

give different color light. By mixing the various powders light of any desired

color including daylight can be obtained.

The glass tube of the fluorescent lamp is provided at both ends with bipin caps

and oxide coated tungsten filaments. The tube contains organ gas with a small

quantity of mercury under low pressure. Even with organ gas the discharge

will not start at ordinary main voltage. A choke and a starter switch are

therefore incorporated in the circuit of the tube lamp to give a momentary high

voltage across the tube to start the discharge. The choke is connected in series

with the tube the starter is connected across tube.

The circuit is suddenly opened at the starter, the flux around the choke collapse

causing a kick of about 1000V. This voltage is applied across the two

electrodes and sufficient to start the discharge of the tube. During the steady

operation of this lamp the voltage across the tube drops to about 150 volts.

This voltage is sufficient to maintain the discharge of the tube.

During the steady operation of this lamp, the voltage across the tube drops to

about 150 volts. This voltage is sufficient to maintain the discharge. The

choke in series with the tube now acts as a stabilizer. A capacitor is connected

across the circuit it improve the power factor.

34


WORKING OF FLUROSCENT TUBE:

The glow starter is a voltage operated type, which is enclosed in a glass bulb

filled with a mixture of helium, and hydrogen is neon or argon. One of the

electrodes is a bimetallic strip. Normally the contacts are open.

When the supply is switched on the potential across the bimetallic electrodes

causes a small glow discharge at a small current not enough to heat up the tube

electrodes. The discharge is enough to heat the bimetallic strips of the switch

causing them to bend and make contact. Now the tube electrodes get preheated

due to flow of large current and the gas in the immediate neighborhood is

ionized. After one or two seconds the bimetallic strips cool down and the

contacts open. This opening of contact in series with the choke causes a

momentary high voltage, which is sufficient to start the discharge in the main

tube.

After the establishment of discharge between the two electrodes, voltage

required to maintain the same is small. As the lamp current flows through the

choke, sufficient voltage drop occurs; they are by allowing only the required

voltage to be applied across the lamp.

It is, therefore, seen that choke performs two functions. 1) It provides

inductive voltage surge to start the discharge. 2) When the lamp is working, it

limits the current in the lamp circuit. Now the voltage available across the

starter is not in a opposition to initiate discharge between its bimetallic

electrodes. A condenser of 0.05mf is put in series with a 100-ohm resistor and

connected across the stator terminal. The checks any condenser surge and

prevents stator contacts from being welded together and minimize radio

interference also the condenser helps to induce high voltage across the choke

by the sudden interruption of current through the stator circuit when the straight

bimetallic strip gets opened.

35


The power factor of the lamp is about 0.5 due to the presence of choke.

Condenser connected across the supply improves the power factor to 0.95. The

fluorescent powders used in the case of low-pressure lamps are solids and are

usually called as “phosphors”. By the use of suitable mixtures of phosphors a

variety of colour can be obtained.

CHAPTER-3

36


DESIGN CALCULATIONS

3.1 DESIGN OF PINION

From PSG design data book (page no.7.18)

dmin > (0.59/ σcmax) х [[Mt]/((1/E1)+(1/E2)) 2](1/3 _________________ (1)

Where,

σcmax = maximum contact compressive stress N/m2

E1, E2 = Young’s modulus N/m2

Mt = Torque N-m

E1 = E2 = 1.1х106 N/m2

Calculation of σcmax

σcmax = HB х CB х Kcl ________________ (2)

Where,

HB = Brinell hardness number

CB = coefficient depends on hardness

Kcl = life factor

Kcl = {[1 x 107]/N} 1/6 _______________ (3)

N = 60 x n x T

Where,

N = rpm

N = life in no. Of cycles

T = life in hours.

= 8000 hours.

From P.S.G design data book (page no.2.4),

CB = 20

37


HB = 200

Substituting the values of N, n, T in the equation [3],

The value of kcl is obtained as 1.139.

Kcl = 1.139.

Substituting the values in equation [2]

σcmax = 20 x 200 x 1.1309

= 4520 x105 N/m2

Calculation of Mt

Mt = 97420 x (Kw/n). ____________ (4)

For power calculation

Centrifugal force, fc = m ω2 r ____________ (5)

M = 7kg

W = m x g

= 2Πn/60

R = 1m

Substituting the values of m, ω, r in equation [4]

fc = 7.56 N.

Downward force, fd = m x g

= 7 x 9.81

= 68.6N.

Centrifugal force, f = fc + fd

= 68.6 + 7.56

= 76.17N

Torque = f x r = 76.17 x 1

= 76.2Nm.

38


Power = Torque x angular velocity.

= 76.2 x 1.05

= 79.7w

Substituting the value of kw and n in equation in [3],

Mt = 776.7

[Mt] = 1.4 x Mt

= 1.4 x 776.7

= 1087.1 N-m

Substituting the values of σcmax, [Mt], E1,E2 in equation [1],

The minimum diameter of the pinion is calculated to be 76.7mm.

We have taken the standard diameter of pinion as 75mm.

Specification Of Pinion

Material : cast-iron

Outside diameter : 75mm

Circular pitch : 4.7mm

Tooth depth : 3.375mm

Module : 1.5mm

Pressure angle : 21

Pitch circle diameter : 72mm

Addendum : 1.5mm

Dedendum : 1.875mm

Circular tooth Thickness : 2.355mm

Fillet radius : 0.45mm

Clearance : 0.375mm

Design of rack

39


Pitch circle diameter of the gear is = 72mm

Circumference of the gear is = pitch circle diameter

= 72

= 226mm

The dimension is for 360 rotation

For 180rotation the rack length is 113 mm

Specification Of Rack

Material : cast iron

Module : 1.5mm

Cross-section :7525mm

Teeth on the rack is adjusted for 113mm

3.2 Design of Springs:

Assume that spring material as chrome vanadium spring steel because it is very

efficient at high stresses and at high temperatures.

Assume spring index as 6,it lies b/w 3-12

Standard wire diameter as 3 mm

C=8

d=3mm

spring index C is defined as the ratio of mean diameter of spring coil to the

wire diameter

C= D/d

By this we can calculate spring coil diameter(D)

D=24mm.

Max allowable stress from the below graph is 550 MPa.

40


Fig 3.3 SAE 1065 spring steel max allowable stress(MPa)

Calculated stress (f):

Helical springs are stressed in torsional and bending.

Torsional shear stress:

f=8FD/(πd^3)

=146.22 MPa

because there is bending as well as torsion, the combined stress

is greater than torsional shear stress only.

Combined stress fc= Ks *f

Ks is Wahl factor

Ks ¿ 0.615c

+ 4c−14 c−4

Ks= 1.2525

41


fc= 183.145 MPa

K= F/x

K is spring constant and x is deflection

x= 30mm

K= 147.15/30

=4.905

No of coils = na= Gd/(8c^3 K)

=17.5= 18

For compression springs n= na+2 = 20

Solid length Ls = d*n = 80 mm

Xallow = 15% x

= 4.5 mm

Total length = L = Ls +X+Xallow

= 114.5 mm

Buckling:

For steel, critical length = 2.57 *D/Ce

Ce is spring seat configuration

Assume Ce as 0.5

Critical length = 128.5 mm > 114.5 mm

The design is safe.

3.4 OUTPUT POWER CALCULATION:

Let us consider,

42


The mass of a body = 60 Kg (Approximately)

Height of speed brake = 10 cm

∴Work done = Force x Distance

Here,

Force = Weight of the Body

= 60 Kg x 9.81

= 588.6 N

Distance traveled by the body = Height of the speed brake

= 10 cm

= 0.10 m

∴Output power = Work done/Sec

= (588.6 x 0.10)/60

= 0.98 Watts

(For One pushing force)

However, this much power produced, it cannot be tapped fully. From the

above purpose we have select to generate electricity by permanent magnet type

D.C generator and store it by 12V lead-acid battery cell.

CHAPTER - 4

DRAWINGS

43


44


45


46


47


CHAPTER-5

WORKING PRINCIPLE

The complete diagram of the power generation using speed brake is given

below. L-angle window is inclined in certain small angle which is used to

generate the power. The pushing power is converted into electrical energy by

proper driving arrangement.

The rack & pinion, spring arrangement is fixed at the speed brake which is

mounded bellow the L-angle window. The spring is used to return the inclined

L-angle window in same position by releasing the load. The pinion shaft is

connected to the supporter by end bearings as shown in fig. The larger sprocket

also coupled with the pinion shaft, so that it is running the same speed of

pinion. The larger sprocket is coupled to the small cycle sprocket with the help

of chain (cycle).

This larger sprocket is used to transfer the rotation force to the smaller

sprocket. The smaller sprocket is running same direction for the forward and

reverse direction of rotational movement of the larger sprocket. This action

locks like a cycle pedaling action.

The fly wheel and gear wheel is also coupled to the smaller sprocket shaft. The

flywheel is used to increase the rpm of the smaller sprocket shaft. The gear

wheel is coupled to the generator shaft with the help of another gear wheel.

The generator is used here, is permanent magnet D.C generator. The generated

voltage is 12Volt D.C. This D.C voltage is stored to the Lead-acid 12 Volt

battery. The battery is connected to the inverter. This inverter is used to convert

the 12 Volt D.C to the 230 Volt A.C. This working principle is already

explained the above chapter. This 230 Volt A.C voltage is used to activate the

light, fan and etc.

48


By increasing the capacity of battery and inverter circuit, the power rating is

increased. This arrangement is fitted in highways; the complete arrangement is

kept inside the floor level except the speed brake arrangement.

Fig 5.1 Working principle

49


Fig .5.2 Experimental view

50


CHAPTER-6

LIST OF MATERIALS

SL.

NO.

NAME OF THE PARTS MATERIAL QUANTITY

1 Model Speed brake

arrangement

Mild Steel 1

2 Spring Steel 4

3 Bearing Steel 4

4 Sprocket C.I 2

5 Fly wheel C.I 1

6 Gear wheel C.I 2

7 Generator (D.C 12 V) Aluminium 1

8 Battery (12 V) Lead-acid 1

9 Inverter 1

10 Chain Steel 1

11 Rack M.S 1

12 Pinion M.S 1

13 Connecting Wire Cu 2 meter

51


CHAPTER-7

ADVANTAGES AND DISADVANTAGES

ADVANTAGES

Power generation is simply running the vehicle on this

arrangement

Power also generated by running or exercising on the brake.

No need fuel input

This is a Non-conventional system

Battery is used to store the generated power

DISADVANTAGES

The major drawback of this POWER HUMP is design of springs. When we

have less traffic and there is difficulty in design of springs also the generation

of power is intermittent, we have to smooth out this variations.

Slight inclination is required in the speed brake

Mechanical moving parts is high

Initial cost of this arrangement is high.

Care should be taken for batteries

52


CHAPTER - 7

COST ESTIMATION

1. MATERIAL COST:

SL.

NO.

NAME OF THE

PARTS

MATERIAL QUANTITY AMOUNT

(RS)

1 Model speed brake

arrangement

(Including Supports)

Mild Steel 1

800

2 Spring Steel 2 280

3 Bearing Steel 4 200

4 Sprocket C.I 2 500

5 Fly wheel C.I 1 120

6 Gear wheel C.I 2 500

7 Generator (D.C 12V) Aluminum 1 800

8 Battery (12 V) Lead-acid 1 650

9 Inverter Electronic PCB 5 meter 2500

10 Chain Steel 1 100

11 Rack M.S 1 350

12 Pinion M.S 1 350

13 Connecting Wire Cu 2 meter 50

TOTAL =7500

53


2. LABOUR COST

LATHE, DRILLING, WELDING, GRINDING, POWER HACKSAW, GAS

CUTTING:

Cost Rs= 600

3. OVERHEAD CHARGES

The overhead charges are arrived by “Manufacturing cost”

Manufacturing Cost = Material Cost + Labour cost

= 7500+600

= 8100

Overhead Charges = 20% of the manufacturing cost

= 1340

TOTAL COST

Total cost = Material Cost + Labour cost + Overhead Charges

= 9440

Total cost for this project = 9440

54


CHAPTER-8APPLICATIONS AND FUTURE SCOPE

APPLICATIONS:

Power generation using speed brake system can be used in most of the

places such as

All highways

All road ways Speed brake

FUTURE SCOPE:

This arrangement is slightly modified to construct in foot step and this

arrangement is fixed in

schools,

cinema theatres,

Shopping complex and

Many other buildings.

With proper improvements in design and installation, we can produce

240v/230v with 5-10A power smoothly and can be used for public use like

streetlights or traffic signals

By these improvements in design it can glow 5 streetlights of 40-watt capacity,

which will consume 2.7 K.W.H. per day.

55


CHAPTER-9

CONCLUSION

Energy is an important input to sustain industrial growth and standard of living

of a country and can be directly related to per-capita energy consumption. The

various types of non-conventional sources of energy are solar energy, wind

energy, biogas etc… now by developing “POWER HUMP” we can generate

power with out utilizing any external sources mentioned earlier.

Now, vehicular traffic in big cities is more, causing a problem to human being.

But this vehicular traffic can also be utilized for power generation by means of

new technique called “POWER HUMP”. If it is placed in heavy traffic roads,

the weight and kinetic energy of the vehicles can be used to produce

mechanical power in shafts and this mechanical power is once again converted

into electrical energy.

As it does not utilize any external source, and traffic will never be reduced,

these power humps are more reliable, and have more life than any other power

source. It is also feasible from the customer point of view.

56


CHAPTER - 10

BIBLIOGRAPHY

Shakun Srivastava , Ankit Asthana JERS/Vol.II/ Issue I/April-June,

2011/163-165

Aswathaman.V IPCBEE vol.1 (2011) © (2011) IACSIT Press,

Singapore

Rai. G.D. “Non Conventional Energy Sources”, Khanna Publishers,

Delhi.

Ramesh. R, Udaya Kumar, K.Anandakrishnan “Renewable Energy

Technologies”, Narosa Publishing House, Madras.

A.K.Sawhney. “A Text Book Of Electrical, Electronics,

Instrumentation And Measurements”

B.L.Therja, A.K. Theraja. “A Text Book Of Electrical Technology”

G.R.Nagpal. “Power Plant Engineering” Khanna Publishers, Delhi.

P.S.G. Data Book

57

Documents

Project Report