Contents - AMIT

8/6/2019 Contents - AMIT

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1.COMPANY PROFILE

Fig.1.1. View of Electronics Department, REIL

Rajasthan Electronics & Instruments Ltd. (REIL) has a prominent place amongst theelectronics industry of Rajasthan. The company is a joint venture between the

Government of India & the Government of Rajasthan, through their respectiveinstitutions. The company was conferred the status of a "MINI RATNA" by the

Department of Public Enterprises, Ministry of Industry, Government of India in 1997 onaccount of it's good all round performance and excellent products.

The company has added another feather in its cap by establishing a Quality Management

system for its operations and has been certified as an ISO 9001 firm W.E.F. 31st July,1998. The area of business extends to manufacturing and marketing of electronic

products/ services in the following areas:

Agro-Dairy Sector Solar Photovoltaic Sector Industrial Electronics Sector Information Technology

In all these sectors, the manufacturing facility is complemented by the departments forthe function of Materials management, Quality Assurance, Research & Development,

Planning & Finance Management along with infrastructure and country wide network ofoffices of marketing and after sales support. The company is self-reliant as far as

development activity is concerned, to enable modification and improvement in existingproducts and also introduce new products, in tune with customer requirement.


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REIL has its headquarters and works at Jaipur, Rajasthan, famous as the Pink City ofIndia known for its palaces, forts, museums and handicrafts all over the world. The city is

well connected by Rail, Road and Air to the two major metros of India-namely NewDelhi & Bombay and forms part of the golden triangle of tourism along with New Delhi

and Agra.

REIL has its registered office & manufacturing facilities situated at the KanakpuraIndustrial area about 12 kms from the heart of Jaipur city and is spread over a sprawling

campus of ten acres, amidst lush green surroundings, with over 2700 sq. meter area ofcovered space. Other offices include the corporate office within the city and Field

maintenance centers (FMCs) and Sub-FMC's spread over most of the regions of thecountry. REIL has used Information technology in its various operations since 1981, the

year of its formation.

The company has substantial in-house infrastructure for software development includingdesktops, servers and application development tools.

REIL has experience and know-how to develop application software for all business

functions on various platforms and architecture. The function typically includes Financeand Accounts, marketing, Material Management, Personnel Management, Production,

Planning and Control, Manufacture and Quality Assurance. The company also hasexperience in writing software for applications and interfacing of desktop system to

various tests and measuring instruments.

REIL is also into end-user solutions for the dairy sectors and the current product includesPC-based Milk Collection System, village-level co-operative accounts management

system and Raw Milk Reception Dock Automation Systems. The software also has multi-lingual features for use in various areas of the country.


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2.COMPANY STRUCTURE

Fig.2.1. Block diagram of company structure

MANAGING DIRECTOR

TSO to MDMANAGEMENTREPRESENTATIVE

ELECTRONICS

&INFORMATIONTECHNOLOGY

FINANCE

MANAGEMENT

PERSONNEL

&INDUSTRIALRELATIONS

DIVISION

RENEWABLE

ENERGYDIVISION

MARKETING(ELECTRONICS)

DEPTT.

RESEARCH

&DEVELOPMEN

T DEPTT.

INFORMATIONTECHNOLOGY

DEPTT.

PLANTMAINTAINANCE

GROUP

QUALITY &ASSURANCE

NEWPROJECTS

WORKS DEPTT.

MARKETING(RENEWABLE

E NERGY)

MATERIALS

MANGEMENT


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3.REIL PRODUCTSProducts manufactured at REIL are divided in the following categories:

Agro Dairy Products SPV Products IT Products Industrial Electronics Products

3.1. Agro Dairy ProductsS.No. Product Application

1 Electronic Milk Tester For measurement of % Fat content in

Milk at Village Milk CooperativeSocieties

2 MilkoScan Total Milk quality parameter

analysis for Dairies

3 Automatic Milk Collection Station For fair & prompt payment tofarmers at Village Milk Cooperative

Societies

4 DP-EMT Low Cost version of Milk Collection

Station for small village MilkCooperatives Societies

5 PC-MCS Personal Computer based version ofMilk Collection Station with

accounting facility

6 Smart Card based PC Milk CollectionStation

For fair & prompt payment tofarmers at Village Milk CooperativeSocieties

7 Raw Milk Reception Dock NetworkAutomation

Process Automation of Raw MilkReception Docks at Dairies

8 Raw Milk Reception Dock SampleAutomation

Milk sample collection andmovement automation at Raw Milk

Reception Dock

Table3.1. Different agro electronics products manufactured at Reil


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3.2. S.P.V. Products

Table3.2. Different SPV products manufactured at REIL

S.No. Product Application

1 SPV Modules Power conversion (Sunlight toelectricity)

2 Street Lighting System Village Street Lighting

3 SPV Water Pumping System Village drinking water supply&

land irrigation

4 SPV Domestic Lighting System

Village community lighting

5 SPV Railway Signaling System

Village unmanned Railwaycrossings

6 SPV Adult Education System For providing lights at village adulteducation centers

7 SPV Power Packs for Battery

Charging

For police check Posts & BSF

communication sets

8 SPV Television For village mass communication

9 SPV Lantern For providing a portable neat and

clean illumination system for use invillage huts, farms, work place, etc

10 SPV Hut Lighting System For providing illumination atvillages huts

11 SPV Power Station For village electrification

12 SPV powered Microwave

Repeater System

For battery charging at Microwave

repeater station

13 SPV Cathodic Protection System

SPV Cathodic Protection System

14 SPV Dusk dawn system For Automatic operation of

Municipal Street Lights


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3.3. I.T. Products


1 Image Processing ApplicationSystem

Preparation of Electoral Photo Identity Card(EPIC) and Visiting card etc.

2 Customized Software

development SS

Computerization of various applications

meant for departments of corporate offices,Industries and other institutions

3 Product Firmware Development

Customized assembly languageprogramming for Microprocessor based

electronic equipment

4 Internet Technologies application

Home page design, development andhosting

5 Education & training Training courses for computer programming

languages and other applications6 Programmable Data Terminals Hand Held Computing through

Programmable Data Terminal (PDT) fordifferent applications like Electronic

Ticketing Machine, Spot Billing Machine,Electronic Parking Machine, Micro

Banking, House tax terminal. TrafficOffence recording system, Point of Sale

terminal etc.

7 Dairy ERP Enterprise Resource Planning (ERP)

package for Dairies. The modules are for

Chilling Centers, Milk procurement,Technical Inputs, Inventory, Purchase,Production, Sales, Marketing, Finance,

Plant maintenance, MIS etc.

Table3.3. Different IT products manufactured at REIL


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3.4. Industrial Electronics Products

Table3.4. Different industrial electronics products manufactured at REIL


1 Single Phase Energy Meter Measurement of Single Phase ElectricPower for domestic applications

2 Three Phase Energy Meter Measurement of Three Phase Electric

Power for domestic applications


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4.ELECTRONIC MILK TESTER4.1. Description

Electronic Milk Tester (EMT) manufactured by REIL has been adopted as an essential

instrument for measuring the milk fat. Percentage of fat content is displayed quickly and

accurately on a digital readout.

Several thousand small/large dairies and Village Milk Collection Centers are being

benefited with its use.

Fig.4.1.1.An Electronic Milk Tester


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4.2. Working

a) Electronic Milk Tester is based on the photometric measurement of light scattered bythe milk sample. The light is scattered by the fat globules, acting as small prisms.

b) Not only fat globules in the milk contribute to the light scattering, but also theproteins may affect the measurement. To eliminate their influence, it is necessary to

dissolve them. EDTA solution is used for this purpose.

c) All the fat globules do not have the same size. The measuring system requires aconstant globule size to provide a mixed relation between the amounts of light

scattered to the fat content.

d) The range of globule size is limited in the milk tester to a very narrow region outsidethe natural range. This is achieved by homogenizing and bringing the globules sizeinto the range of 0.5 to 1.5 microns.

e) Light rays from a photo lamp passed through the layer of fluid in the curette and arescattered according to the sample of fat globules in the sample. More the fat present

in the curette, more is the light scattered and less light passes through the curette.

f) The rays that do pass through the curette strike a photocell, producing a currentproportional to the light intensity. The current is fed to a digital readout unit which

gives direct fat percentage readout.

4.3. Features

a) Auto zero facility.b) Quick and instant read-out.c) Easy to read digital LED display.d) Runs on mains or battery.e) Measures up to 13% fat.f) Accepts small sample volume.g) Performs 120-150 tests per hour.h) Built-in battery charger.i) Close correlation to accepted standard methods.

j) Automatic switch-over to battery in case of power failure.


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4.4. Production Process

In the production of EMT, various stages for production are as follows:

A. Cable assembly unit:In this all cables are assembled for different purposes use in EMT.

B. Charging regulator:In this unit the charging regulators manufactured which is used for charging the

batteries at required power supply.

C. Switch Unit:In this unit various type of switches used for control the function of EMT.

D. Measure PCB:It is manufactured for the measuring purpose where all components are mounted.

E. Homogenizer:It is used to break the uneven fat globules in equal size.

F. Thermo Block:This is used to maintain the temperature of milk & machine.

G. Valve Unit:In this unit of EMT various inlet / outlet valves are assembled for suction of milk

& EDTA solution.

H. Output Lever:This is fully mechanically designed unit basically for homogenization of milk in

homogenizer & for easy uses in rural areas.

I. Photometer:The photometer consists of a lamp, lamp housing and detector assembly, the

detector assembly includes the curette and photocell.


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a. Curette: It is made of two hardened glass discs. One has a ground depressionof 0.4 mmthe other has two small holes to provide inlet and outlet to the

corvette.

b. Photocell:It is a selenium barrier/silicon detector photocell. Care should betakennotto expose this photocell to light when not in operation.

c. Lamp:12 Volts tungsten Lamp

Fig.4.2. Photometer assembly


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5.VARIANTS OF ELECTRONIC MILK TESTER

5.1.Automatic Electronic Milk Tester

Fig.5.1. Automatic electronic milk tester

Automatic Electronic milk tester (Auto EMT) manufactured by REIL is simple,economical and accurate milk fat testing instrument. Manual operation has been

automated by using high torque AC synchronous motor to make more reliable, rugged &to ensure proper homogenization for higher fat sample. Percentage of fat content is

displayed quickly and accurately on a digital read.

The measuring procedure in EMT follows the automated system of dilution, mixing,homogenization and photometric measurement. It provides instant measurement of milk

fat and has high speed of operation. Consequently much time will be saved in case oflarge number of measurements.


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5.2. Data Processor Electronic Milk Tester (DPEMT)

Fig.5.2.1. Setup of DPEMT

Data Processor Electronic Milk Tester (DPEMT) comprises of four main units, anElectronic Milk Tester, Milk Weighing System. Remote Display & Dot Matrix

Printer.EMT measurers the fat content of the milk. The membership code of individual

members is entered manually by a keyboard. The weight can be entered either manuallyor captured automatically.

The equipment gives the printout of the transaction of the milk brought in by eachproducer. The member no., weight, fat, amount are displayed on DPEMT and Remote

Display simultaneously. A shift-end summary can be printed at the end of the shift.


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5.2.1. Features

a) Auto zero facility.b) Centralized testing & payment.c) Instant measurement & display of milk fat.d) Performs 120-150 samples per hour.e) Instant calculation of amount payable.f) Built-in battery charger.g) Fast & economical.h) Close correlation to accepted standard methods.i) Runs on mains & battery.j) Slip printout by 19 column numeric printer.k) Operation with hexadecimal keyboard.l) Suitable for interface with PC through RS232 port.m)

Facility to feed milk weight directly through key.

n) Suitable for interface with electronic weighing pad in absence of weighing unitmachine through parallel port.


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5.3. Smart Automatic Milk Collection Station (SAMCS)

Fig.5.3 Setup of SAMCS

The Smart PC Based Milk Collection Station is specially designed integrated system,

which is a combination of several units viz, AZ Electronic Milk Tester, Milk WeighingSystem, Personal Computer with smart and reader/writer & 80-column Printer. It is

integrated with software support for milk collection and Society Accounts Management.The system is suitable for instant weighing of the Milk, measurement of Fat content andcalculating the amount payable to the member based on FAT & Weight.

The smart card serves the purpose of member identification and acts as an Electronic PassBook for the member wherein his/her milk transaction data is stored. The system can alsobe used later for maintaining the complete records of the collection centre together with

details of all transactions of the village co-operative society.

This system can perform 120-150 operations in an hour. The sequence of operationrequire, insertion of smart card, pouring of milk in a weighing container, collection of

milk sample at the time of pouring, measurement of fat content, calculation of paymentand printing of payment slip.


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5.3.1. Block diagram

Fig 5.4 Block diagram of SAMCS

5.3.2. Features

a) Proper authentication and identification of the member farmer using Smart Cardwhich is also an electronic pass book for the payment cycle.

b) Instant measurement of fat, weight and calculation of amount payable.c) Instant measurement of fat, weight and calculation of amount payable.d) Centralized testing and payment.e) Print out of shift end/ ten days/ monthly/ yearly summary.f) Computation of the activities of the society in a cost effective manner.g) Provide higher degree of automation.h) Representative reports:

- Society reports.- Member reports.

- Share reports.- Milk collection reports.

- Inventory reports.- Business associates reports.

- Service reports.- Accounting reports

Auto Zero

Electronic

Milk Tester

Milk

Weighing

System

Personal computer with

collection & accountsmana ement ftware

80-Column printer with

slip printing facility

Smart card

reader/writer


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6. SOLAR CELLS

6.1. Introduction

Solar cells represent the fundamental power conversion unit of photovoltaic system. Theyare made from semiconductors and have much in common with other solid-stateelectronic devices.

Various types of solar cells are available in the market like crystalline Si solar cells,Multi-crystalline silicon cells, amorphous silicon cells, thin film cells and high efficiency

cells. The maximum conversion efficiency observed in lab devices has exceeded 30% butefficiency of commercial cells lie between 15-25%.

Fig.6.1. Single solar cell

Sometimes the term solar cell is reserved for devices intended specifically to captureenergy from sunlight such as solar panels and solar cells, while the term photovoltaic cell

is used when the light source is unspecified. Assemblies of cells are used to make solarpanels, solar modules, or photovoltaic arrays.

Photovoltaic is the field of technology and research related to the application of solar

cells in producing electricity for practical use. The energy generated this way is an

example of solar energy (also known as solar power).


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6.2. Applications and Implementation

Solar cells are often electrically connected and encapsulated as a module. Photovoltaic

modules often have a sheet of glass on the front (sun up) side, allowing light to passwhile protecting the semiconductor wafers from the elements (rain, hail, etc.). Solar cells

are also usually connected in series in modules, creating an additive voltage. Connectingcells in parallel will yield a higher current. Modules are then interconnected, in series or

parallel, or both, to create an array with the desired peak DC voltage and current.

The power output of a solar array is measured in watts or kilowatts. In order to calculatethe typical energy needs of the application, a measurement in watt-hours, kilowatt-hours

or kilowatt-hours per day is often used. A common rule of thumb is that average power isequal to 20% of peak power, so that each peak kilowatt of solar array output power

corresponds to energy production of 4.8 kWh per day (24 hours x 1 kW x 20% = 4.8kWh).

To make practical use of the solar-generated energy, the electricity is most often fed intothe electricity grid using inverters (grid-connected photovoltaic systems); in stand-alonesystems, batteries are used to store the energy that is not needed immediately.

Solar cells can also be applied to other electronics devices to make it self-powersustainable in the sun. There are solar cell phone chargers, solar bike light and solar

camping lanterns that people can adopt for daily use.

6.3. Working Principle

The solar cell operation is based on the ability of semiconductors to convert sunlightdirectly into electricity by exploiting the photovoltaic effect. In the conversion process,the incident energy of light creates mobile charged particles in the semiconductor, which

are then separated by device structure and electric field present at junction, and produceelectric current. When an electron hole pair is generated by photon then immediately after

their generation electrons and holes decay to states near to edges of their respective bandgaps. This excess energy is lost as heat and adds to losses in the cell.

6.4. Photo generation of charge carriers

When a photon hits a piece of silicon, one of three things can happen:

1. The photon can pass straight through the silicon this (generally) happens for lowerenergy photons,

2. The photon can reflect off the surface,3. The photon can be absorbed by the silicon, if the photon energy is higher than the

silicon band gap value. This generates an electron-hole pair and sometimes heat,

depending on the band structure.


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When a photon is absorbed, its energy is given to an electron in the crystal lattice.Usually this electron is in the valence band, and is tightly bound in covalent bonds

between neighboring atoms, and hence unable to move far. The energy given to it by thephoton "excites" it into the conduction band, where it is free to move around within the

semiconductor. The covalent bond that the electron was previously a part of now has one

fewer electron this is known as a hole. The presence of a missing covalent bondallows the bonded electrons of neighboring atoms to move into the "hole," leavinganother hole behind, and in this way a hole can move through the lattice. Thus, it can be

said that photons absorbed in the semiconductor create mobile electron-hole pairs.

A photon need only have greater energy than that of the band gap in order to excite anelectron from the valence band into the conduction band. However, the solar frequency

spectrum approximates a black body spectrum at ~6000 K, and as such, much of the solarradiation reaching the Earth is composed of photons with energies greater than the band

gap of silicon. These higher energy photons will be absorbed by the solar cell, but thedifference in energy between these photons and the silicon band gap is converted into

heat (via lattice vibrations called phonons) rather than into usable electrical energy.

6.5.Charge carrier separation

There are two main modes for charge carrier separation in a solar cell:

1. Drift of carriers, driven by an electrostatic field established across the device2. Diffusion of carriers from zones of high carrier concentration to zones of low

carrier concentration (following a gradient of electrochemical potential).

In the p-n junction solar cells the dominant mode of charge is by diffusion. However, in

thin films (such as amorphous silicon) the main mechanism to move the charge is theelectric field and therefore the drift of carriers.

6.6. The p-n junction

The most commonly known solar cell is configured as a large-area p-n junction madefrom silicon. As a simplification, one can imagine bringing a layer of n-type silicon into

direct contact with a layer of p-type silicon. In practice, p-n junctions of silicon solar cellsare not made in this way, but rather by diffusing an n-type dopant into one side of a p-

type wafer (or vice versa).

If a piece of p-type silicon is placed in intimate contact with a piece of n-type silicon,then a diffusion of electrons occurs from the region of high electron concentration (the n-

type side of the junction) into the region of low electron concentration (p-type side of the


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junction). When the electrons diffuse across the p-n junction, they recombine with holeson the p-type side. The diffusion of carriers does not happen indefinitely, however,

because charges build up on either side of the junction and create an electric field. Theelectric field creates a diode that promotes charge flow, known as drift current that

opposes and eventually balances out the diffusion of electrons and holes. This region

where electrons and holes have diffused across the junction is called the depletion regionbecause it no longer contains any mobile charge carriers. It is also known as the spacecharge region.

6.7. Equivalent circuit of solar cell

To understand the electronic behavior of a solar cell, it is useful to create a model whichis electrically equivalent, and is based on discrete electrical components whose behavior

is well known. An ideal solar cell may be modeled by a current source in parallel with adiode; in practice no solar cell is ideal, so a shunt resistance and a series resistance

component are added to the model.[4]

The resulting equivalent circuit of a solar cell isshown on the left. Also shown, on the right, is the schematic representation of a solar cell

for use in circuit diagrams.

Fig.6.7.1. Equivalent circuit of solar cell Fig.6.7.2. Circuit symbol

6.8. Cell temperature

Temperature affects the characteristic equation in two ways: directly, via T in theexponential term, and indirectly via its effect on I0 (strictly speaking, temperature affects

all of the terms, but these two far more significantly than the others). While increasing Treduces the magnitude of the exponent in the characteristic equation, the value of I 0

increases exponentially with T. The net effect is to reduce VOC (the open-circuit voltage)

linearly with increasing temperature. The magnitude of this reduction is inverselyproportional to VOC; that is, cells with higher values of VOC suffer smaller reductions involtage with increasing temperature. For most crystalline silicon solar cells the change in

VOC with temperature is about -0.50%/C, though the rate for the highest-efficiencycrystalline silicon cells is around -0.35%/C. By way of comparison, the rate for

amorphous silicon solar cells is -0.20%/C to -0.30%/C, depending on how the cell ismade.


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The amount of photo generated current IL increases slightly with increasing temperature because of an increase in the number of thermally generated carriers in the cell. This

effect is slight, however: about 0.065%/C for crystalline silicon cells and 0.09% foramorphous silicon cells.

The overall effect of temperature on cell efficiency can be computed using these factorsin combination with the characteristic equation. However, since the change in voltage ismuch stronger than the change in current, the overall effect on efficiency tends to be

similar to that on voltage. Most crystalline silicon solar cells decline in efficiency by0.50%/C and most amorphous cells decline by 0.15-0.25%/C. The figure above shows

I-V curves that might typically be seen for a crystalline silicon solar cell at varioustemperatures.

6.9. Parameters of solar cell

6.9.1. Series resistance

As series resistance increases, the voltage drop between the junction voltage and theterminal voltage becomes greater for the same flow of current. The result is that the

current-controlled portion of the I-V curve begins to sag toward the origin, producing asignificant decrease in the terminal voltage V and a slight reduction in ISC, the short-

circuit current. Very high values of RS will also produce a significant reduction in ISC; inthese regimes, series resistance dominates and the behavior of the solar cell resembles

that of a resistor. Losses caused by series resistance are in a first approximation given byPloss=VRsI=I

2RS and increase quadratically with (photo-) current. Series resistance losses

are therefore most important athigh illumination intensities.

6.9.2. Shunt resistance

As shunt resistance decreases, the current diverted through the shunt resistor increases fora given level of junction voltage. The result is that the voltage-controlled portion of the I-

V curve begins to sag toward the origin, producing a significant decrease in the terminalcurrent I and a slight reduction in VOC. Very low values of RSH will produce a significant

reduction in VOC. Much as in the case of a high series resistance, a badly shunted solarcell will take on operating characteristics similar to that of resistor.


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6.9.3. Reverse saturation current:

If one assumes infinite shunt resistance, the characteristic equation can be solved for VOC:

Thus, an increase in I0 produces a reduction in VOC proportional to the inverse of the

logarithm of the increase. This explains mathematically the reason for the reduction in

VOC that accompanies increases in temperature described above. The effect of reversesaturation current on the I-V curve of a crystalline silicon solar cell is shown in the figure

to the right. Physically, reverse saturation current is a measure of the "leakage" of carriersacross the p-n junction in reverse bias. This leakage is a result of carrier recombination in

the neutral regions on either side of the junction.

6.9.4. Energy conversion efficiency:

A solar cell's energy conversion efficiency (, "eta"), is the percentage of power

converted (from absorbed light to electrical energy) and collected, when a solar cell isconnected to an electrical circuit. This term is calculated using the ratio of the maximum

power point, Pm, divided by the input light irradiance (E, in W/m2) under standard test

conditions (STC) and the surface area of the solar cell (Ac in m2).

STC specifies a temperature of 25 C and an irradiance of 1000 W/m2

with an air mass

1.5 (AM1.5) spectrums. These correspond to the irradiance and spectrum of sunlightincident on a clear day upon a sun-facing 37-tilted surface with the sun at an angle of

41.81 above the horizon. This condition approximately represents solar noon near thespring and autumn equinoxes in the continental United States with surface of the cell

aimed directly at the sun. Thus, under these conditions a solar cell of 12% efficiency witha 100 cm

2(0.01 m

2) surface area can be expected to produce approximately 1.2 watts of

power.

The efficiency of a solar cell may be broken down into reflectance efficiency,

thermodynamic efficiency, charge carrier separation efficiency and conductive efficiency.The overall efficiency is the product of each of these individual efficiencies.


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7. SOLAR PHOTOVOLTAIC MODULES

7.1. Introduction

A group of cells connected in series or in parallel and then properly laminated over aglass after curing is known as a module. These modules are then fitted onto the areas

receiving sunlight. More often these are placed so that the upper part of the module is inthe South direction. Solar modules of different wattage and made as per orders and

requirements. These are all designed to charge a 12-B battery. The approximate o/pvoltage of a module is 16V-18V. Different types of modules are:

Fig.7.1.1. Different types of SPV Modules


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Solar photovoltaic modules are of following power

a) 18 Watt Module: For making this, 36 cut cells are used. They are connected inseries. The o/p voltage is approximately 0.45 V to 0.5 V and the o/p current is approx.

2.2A. To get required power 36 cut-cells are connected in series. This 36 cells seriesis called a string. The o/p of this string, when illuminated by the sunlight is found to

be approx. 38 watts. It has 4 rows, each containing 9 cells.

b) 75 Watt Module: Here also, a total of 36 cells are connected in series, which iscalled a string. But the cells are Suido-Square having o/p voltage 0.45V-0.5V & o/p

current 4.5. The o/p power of the string is found to be approx 75 watts. It also has 4

rows, each containing 9 cells.

c) 150 Watt Module: These are also designed by Suido-Square cells. A total number of72 cells are connected in series. The module has 6 rows and each row contains 12

cells. Thus a total of 12*6=72 cells are used. The o/p voltage, current and power of

each cell is the same as that in that of 75-watt module. The total power obtained is

approx. 150 watt.


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7.2. Production process of S.P.V. modules

a) Tabbing: This is the process of making terminals of a bare cell by soldering

Copper Strips to the bus bar.

b) Row making: A row of 9 cells is made by connecting positive surface of one cell

to the negative cell of another cell.

c) Stringing: Four rows are connected in series to give a total of 36 cells in series

connection. This assembly is called a string and the process is called as stringing.

d) String checking: This string is checked visually for any kind of faults, which are

as follows:

i) Reverse Stringii) Dry Pointiii)Dry Solderingiv)Loose Connectionsv) Chip (Micro Broken)

e) Lay-up: Lay-up is the process of placing laminating materials to the either sides

of the string. The laminating materials are as listed:

i) Top Glass (Toughened Glass)ii) E.V.A. (Ethylene Vinyl Acetate) Sheetiii)Crane Glassiv)Polyester Toddler

f) Lamination: The above laminating materials are attached to the string both sidesby the process of lamination. This process takes place at 110oC in the laminating

press. The module after lay-up is placed in the press for 11 minutes, which is

equivalent to one cycle of the press.


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First five minutes, soaking takes place. This is the process to generate true

vacuum in the module. Each air particle is stored from the inner part of the

module, after these five minutes, heating takes place for three minutes. And for

last three minutes, the heated module is pressed to attain a one-piece assembly.

g) Curing: This process comes after the lamination to attain the full strength of

laminating materials. For this, the module is placed into 120oC temperature for 20

minutes.

h) Trimming: The resultant modules from curing process have some extra

laminating materials. These materials are then cut and final module is then

obtained.

i) Electrical inspection: This inspection is done to check the performance of the

module.

j) Channeling:Now to provide structural support to the module, channels are fixed

around it. These channels prevent any damage to the module. A terminal box is

also fitted for external connections and mountain of safety diodes and then the

final product is cleaned and sent to the finished goods store.


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8. APPLICATIONS OF SOLAR PHOTOVOLTAIC

MODULES

8.1. S.P.V. Domestic Lightening System

This system provides un-interrupted light and is completely noiseless, smoke-free and

free from fire hazards. The independent lighting system consisting of 2 CFL fixtures, astorage battery powered by the SPV Module provides 4 hours of light per day. During

day time SPV module charges the battery. At night battery operates CFL bulbs andprovides light in remote areas.

Fig 8.1 SPV lighting system installed at a village in Barmer district, Rajasthan

8.1.1. Uses

a. Rural areas which have no grid supply.b. Farm Houses.c. Urban house holds which face frequent power cutsd. Out-of-the-way holiday locations.e. Holiday cottages & caravans.


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8.2. S.P.V. Railway Signaling System

Fig.8.2.1. SPV module fitted over railway signal

REIL's SPV modules are approved by R.D.S.O. Ministry of railways vide their approval

no. STS / E / cell solar dated 16. 10. 95. REIL has supplied and installed over 300 SPVsignaling systems on various sections of western railways.

These systems are working satisfactorily under adverse climatic conditions of very hightemperature, dust-storms, etc. description applications the railway signaling system

consists of an SPV module, a battery, a signaling PCB to energize front & back bulb ofthe signal and provide indication in the signal room. Acharge control unit protects the

battery from over charge and under voltage. Also, it automatically turns on the lamps innight and shuts them off during the day.

The system is designed for use by the railways. The system provides reliableandeconomicalpower for energizing the signal motor and lamps at isolated railway

signals that are far from grid power.


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8.2.1 Features

a) Highly Modular in nature.b) Little or no maintenance required.c) Non-polluting in nature.d)

Depends on inexhaustible source of energy.

e) Easy to operatef) No recurring costg) Automatic operation - No manpower required.

8.3. S.P.V. Dusk-Dawn System

Fig.8.3.1. SPV dusk dawn system

Solar Photo Voltaic (SPV) Dusk Dawn System is an energy saving device used forautomatic switching of street lighting systems, making proper use of grid power and

increasing the life of the lamps by switching the street lights for a optimum period. Thesystem is highly reliable and efficient for years of continuous flaw-less operation. The

system's operation is based on sensing the ambient light level which actuates theelectronic controller to switch ON the street lights in the evening and switch OFF in the

morning.

The sensor is totally maintenance free and encapsulated in an environment proof housingmaking it more reliable even in adverse atmospheric conditions. The system has the

advantage of automatic setting of switching timings irrespective of whether it is winter orsummer, thus making it a totally unmanned operation. Once a setting for a particular

darkness level is done, it remains unchanged throughout the year.


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8.3.1. Features

a) Automatic switching and hence unmanned operation.b) Optimal use of grid power.c) Energy saving up to 30%.d) Enhancement of pole-lamp life.e) Highly efficient, reliable and economical.f) System design can take care of any grid load / safety precautions.g) No seasonal time setting required.h) Highly weather proof and totally maintenance free sensor.i) Protection against line to line, line to neutral & line to earth fault.j) Manual by-pass in case of system failure.k) On Line service facility.

8.4. Solar Lantern

Fig.8.4 Different solar lanterns

Solar Lantern is an advanced portable solar photo voltaic lighting system ideal for remotearea / village dwelling. It is pollution-free and an excellent replacement for conventional

kerosene lamps and lanterns. The portable Solar Lantern has a CFL lamp, sealedmaintenance free battery and electronics all placed in an elegant housing. The solar

energy generated by the SPV module is stored in the battery which in turn powers thehighly efficient and compact fluorescent lamp.


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8.4.1 Uses

a) Remote homeb) Emergency lightc) Roadside vendors / hawkersd) Campers hut lighte) Night schoolsf) Night patrollingg) Forest Check Post

8.5. Solar Water Pumping System

Solar photovoltaic water pumping system is modular, flexible and are of two basic types

i.e. Shallow well type & Deep well type. The pumping system are extremely rugged,maintenance free & do not need any other external source of power. D.C. power is

generated at site itself and fed to the pump. They are ideally suitable for those areaswhere conventional grid supply is either erratic or non-existent. Also SPV pumps require

only one time investment with no recurring cost and have a long life.

8.5.1. Uses

a. Drinking water.b. Irrigation.c. Agriculture related use.d. Horticulture.e. Animal Husbandry.f. Poultry farming.g. High value corps.

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