reil3

VIVEKANANDA INSTITUTE OF TECHNOLOGY (EAST)

INTRODUCTION

Rajasthan Electronics & Instruments Ltd. (REIL) is a public sector unit and it has a prominent place amongst the electronics industry of Rajasthan. It was established in 1981. REIL has joint venture between the Government of India & the Government of Rajasthan, through their respective institutions. REIL is an ISO 9001 public sector undertaking started as a joint venture between RIICO ( Rajasthan State Industrial Development & Investment Corporation) and Instrumentation Limited, Kota. The company was conferred the status of a MINI RATNA by the Department of Public Enterprises, Ministry of Industry, Government of India in 1997 on account of its good all round performance and excellent products. The company has added another feather in it is 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 are:

Agro-Dairy Sector Renewable energy Sector Industrial Electronics Sector Information Technology

In all these sectors, the manufacturing facility is complemented by the departments for the function of Materials management, Quality Assurance, Research & Development, Planning & Finance Management along with infrastructure and country wide network of offices of marketing and after sales support. The company is self-reliant as far as development activity is concerned, to enable modification and improvement in existing products and also introduce new products, in tune with customer requirement. REIL aims at retaining its primacy in the area of rural electronics, Non- conventional Energy Systems and Information Technology by developing, manufacturing and marketing quality services. REIL has played a vital role in the field of rural development in India- bringing appropriate rural electronics technology to thousands of villages all over the country. REILs

1ELECTRONICS AND COMMUNICATION DEPARTMENT


products range from Electronic Milk Testers and allied dairy equipment to Solar Photovoltaic modules systems. The company, though its market of Science and Technology, Government of India, has developed and introduced a number of new products such as Data Processor Electronic Milk Tester (DPEMT), Electronic Milk Weighed System, Raw Milk Reception Dock (RMRD) Automation Database Management System, Smart Automatic Milk Collection Station (SAMCS), Auto Zero EMT, Solar EMT in the diary sector. REIL is also in the business of Renewable Energy through Solar Photo Voltaic (SPV) Technology where it started its operations in 1986, with manufacture of SPV Modules and Systems. Since then it has supplied and installed numerous SPV Stand alone Street Lighting System, SPV de-centralized Domestic Lightening System, SPV drinking Systems, SPV dusk dawn Switching Systems, Microwave Repeate4r Stations, Satellite Ground Terminals and Grid Interactive Power Plants etc. In this area company has produced SPV modules of about 8 MW generating capacity. The company entered the area of Renewable Energy through Solar Photo Voltaic (SPV) technology, in the year 1985. The company started its operations with manufacture of SPV Modules and control electronics for SPV powered village Street Lights. During my training I have gone through the four department of REIL these are Renewable energy division, agro dairy division, industrial electronics division and quality assurance department.



RENEWABLE ENERGY DIVISIONThe REIL entered into the Solar Photovoltaic industry in 1985. It started its operations by setting up a manufacturing facility for SPV modules and has expanded its area of operations through manufacture of Balance of Systems for a large number of applications, utilizing its electronics product manufacturing facility. The company products are a result of its own in-house development efforts. The company has a capacity of 2 MW per year on single shift basis. Solar photovoltaic based application products, sub systems and integrated systems most of which are developed in-house. In the SPV segment, the company manufactures SPV modules and application systems including Domestic Lighting System, Street Lighting System, etc. In renewable energy division REIL offers a wide range of state of the art Solar Photovoltaic module suitable for a variety of applications. These modules are ideal power generation at remote areas, where conventional power is not available or power supply is erratic. It is noiseless, non-polluting and maintenance free source of energy.

Solar Photovoltaic ModuleREIL are using the conventional resources of energy from many years. But now, they are scarce and may not be available in forgoing decades. Hence company has to switch over to other source of energy. One of these is Solar Energy, which is unlimited. Hence this alternate is the need of the future. To utilize this resource of energy, REIL use solar cells, which convert solar energy into electrical energy. A solar cell generates approximately 0.5 volts. Higher voltages and current are obtained by connecting these cells in series or parallel; according to the requirement. This energy is stored in batteries and can be used in night hours. The word Photovoltaic is combination of the Greek word for light and the name of the physicist Allesandro Volta. It identifies the direct conversion of sunlight into energy by means of solar cells. The conversion process is based on the Photoelectric Effect. The Photoelectric Effect describes the release of positive and negative charge carriers in a solid state when light strikes its surfaces.



Photovoltaic are solid-state semiconductor devices that convert light directly into electricity. They are usually made of silicon with traces of other elements and are similar to transistors, light emitting diodes (LEDs), and other electronic devices. The photovoltaic device (usually called a solar cell) consists of layers of semiconductor materials with different electronic properties. Most of the material is silicon. A thin layer on the front of the cell is treated with phosphorous to give it a negative character. The interface between two layers contains an electric field and is called a junction. Light consists of particles called photons. As shown in fig 1: we can easily understand when light hits the solar cell, some of the photons are absorbed in the region of the junction, freeing electrons in the silicon. If the photons have enough energy, the electrons will be able to overcome the electric field at the junction and are free to move through the silicon and into an external circuit. Some of the more commonly available units generate 5W to 10W per square foot of the collector surface. The direct current (DC) from the solar panel is converted to alternating current (AC) through an inverter.

Silicon:Silicon is important past of solar cell. Solar cell is made up of silicon. It has some special chemical properties, especially in its crystalline form. An atom of silicon has 14 electrons, arranged in three different shells. The first two shells, those closest to the center, are completely full. The outer shell is only half full having only four electrons. A silicon atom will always look for ways to fill up its last shell would like to have eight electrons. To do this it will share electrons with four of its neighbor silicon atoms. Its like every atom holds hands with its neighbors, except that in this case each atoms has four hands joined to four neighbors. Pure silicon is poor conductor of electricity because none of its electrons are free to move about as electrons are in good conductor such as copper. Instead the electrons are all locked in the crystalline structure. The silicon in a solar cell is modified slightly so that it will work as a solar cell.



Silicon in Solar Cells:A solar cell has silicon with impurities other atoms mixed in with the silicon atoms. Consider silicon with an atom of phosphorus here and there, may be one for every million silicon atoms. Phosphorus has five electronics in its outer shell, not four. It still bonds with its silicon neighbor atoms,but in a sense, the phosphorous has one electron that doesnt have anyone to hold hands with. It does not for part of bond, but there is a positive proton in the phosphorous nucleus holding it in place. When energy is added to pure silicon, as in the form of heat, it can cause a few electrons to break free of their bonds and leave their atoms. A hole is left behind in each case. These electrons then wander randomly around the crystalline lattice looking for another hole to fall into. These electrons are called free carriers and can carry electrical current. There are so few of them in pure silicon, however, that they arent very useful. It turns out that it takes a lot less energy to knock loose one of our extra phosphorous electrons because they arent tied up in a bond- their neighbors arent holding them back. As a result, most of these electrons do break free, and we have a lot more free carriers than we would have in pure silicon. The process of adding impurities on purpose is called doping and when doped with phosphorous, the resulting silicon is called N-type because of the prevalence of free electrons. N-type doped silicon is a much better conductor than pure silicon. That is only one part of solar cell is N-type the other part is doped with Boron; which has only three electrons in its outer shell instead of four to become P-type silicon. Instead of having free electrons, P-type silicon has free holes. Holes really are just the absence of the electrons, so they carry the opposite (positive) charge, they move around just like electrons do.

N-type plus P-type Silicon:In photovoltaic module both N-type silicon and P-type silicon photovoltaic cell always has at least one electric field. Without an electric field, the cell would not work and this electric field is formed when the N-type and P-type silicon are in contact. The mechanism of producing electric field is explained by figure 1 the free electrons in the N side looks all holes to fall into, the free holes on P side, and theres a mad rush to fill them in. silicon was all electrically neutral. The



extra electrons were balanced out by the extra protons in the phosphorous and the missing electrons (holes) were balanced out by the missing protons in the Boron. At the junction electrons and protons are mixed and form a barrier, making it harder and harder for electrons on the N side to cross to the P side. Eventually, equilibrium is reached and we have electric field separating the two sides.

Solar Photovoltaic Cell:Solar cells are also called photovoltaic (PV) by solar cell scientists. They convert sunlight direct into electricity. Solar cells are often used to power calculators and watches. They are made of semi-conducting materials similar to those used in computer chips. When sunlight is absorbed by these materials, the solar energy knocks electrons loose from their atoms, allowing the electrons to flow through the material to produce electricity. This process of converting light (photons) to electricity (voltage) is called the Photovoltaic (PV) Effect.

Fig. 1 Solar Cell Photovoltaic (PV) is the field of technology and research related to the application of solar cells for energy by converting solar energy (sunlight, including ultra violet radiation) directly into electricity. Due to the growing demand for clear sources of energy, the manufacture of solar cells and photovoltaic arrays has expanded dramatically in recent years. Photovoltaic is the direct conversion of light into electricity at the atomic level. Some materials exhibit a property known



as the photoelectric effect that causes them to absorb photons of light and release electrons. When these free electrons are captured an electric current results that can be used as electricity. Photovoltaic cells are connected electrically in series or parallel circuits to produce higher voltages, currents and power levels. Photovoltaic modules consist of PV cell circuits sealed in an environmentally protective laminate, and are the fundamental building blocks of PV systems. Photovoltaic panels include one or more PV modules assembled as a pre-wired, field-installable unit. A photovoltaic array is the complete power-generating unit, consisting of any number of PV modules and panels.

TYPES OF CELLS, Depending on crystal structure of SiliconSolar cells can be categorized into five classes, depending upon their crystal structure. These are as follows:

(a) Crystalline Silicon CellIt has high mechanical strength and these are less degraded with time. This is made using crystallization of Si around one Si crystal hence it is called Single Crystalline Si Cell. It is best suited for general purpose application. Float zone- efficiency is 23% CZ (commercial) efficiency is 13%

(b) Multi-Crystalline Silicon CellIt is made by crystallization of Si around many crystals of silicon. It has less mechanical strength than single crystalline Silicon material. Efficiency of this cell is 12%

(c) Amorphous Silicon CellThis cell does not have any Si crystal, simply spreading a layer of P-type Si powder and then N-type Si powder over it. Its mechanical strength is very low. Efficiency is 20%. (d) Thin Film Silicon Cell



It is made by very thin film of Si P-type and N-type materials and is used for special purpose. Efficiency is 25%. (e) High Efficiency Silicon Cell The purification of Si in this type of cell is very high. Hence its efficiency is high. It is used for laboratory devices having efficiency up to 30%. Example:Cadmium Telluride Efficiency is 28%.

Types of different Modules used:There is different type of solar module which I saw in REIL during my summer training period. A group of cells connected in series or in parallel and then properly laminated over a glass after curing is known as module. These modules are then fitted onto the areas receiving sunlight. More often these are placed so that upper part of the module is in the South Direction. Solar modules of different wattage and made as per orders and requirements. These are all designed to charge 12-V battery. The approximation o.p voltage of a module is 16V- 18V. Modules are made of following powers: (a) 18 WATT Module: For making this, 36 cut cells are used. They are connected in series. The output voltage is approximately 0.45V to 0.50V and the output current is approx 2.2A. To get a required power 36 cut cells are connected in series. This 36 cell series is called a string. The output 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 is called string. But the cells used are Suido-Square having output voltage 0.45V-0.50V and output current 4.5A. the output power of the string is found to be approximately 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 of 72 cells are connected in series. The module has 6 rows and each row contain 12 cells. Thus a total of 12*6=72 cells are used. The output voltage, current and power of each cell is the same as that of 75-watt module. The total power obtained is approximately 150 watts.

Fig. 2 Solar Photovoltaic Modules

Construction &Principle operation of Solar Cell:In training period I learned construction method of solar cell. Solar cell is a simple p-n junction. It is made up of silicon, since in Si, the minority carrier concentration is low, hence they do not disturb the flow of electrons and holes, generated by the solar energy. Less charge carriers can get higher value of current and power. For making p-n junction, it is doped with gaseous Boron (p-type) from one side and solid phosphorous (n-type) from the other side. The doping concentration is taken same for both the impurities. Due to different doping state difference of impurities (i.e. gaseous and solid), a one side shifted p-n junction is formed. This junction is



shifted towards the n-side. Hence the light is always made to incident at the n-side so that the photons can reach the junction. When the high-energy photons reach the depletion region, they impart sufficient energy to an electron to break its covalent bond. This electron comes in conduction band and begins to behave free electron. At the same instant, a hole is also generated due to broken covalent bond. Hence, we can say that two charge carriers are generated by one high-energy photon. These carriers move to opposite direction due to potential barrier at the junction and constitute a current. One must condition of generation of mobile charge carrier is that the incident photon must have higher energy than the band gap of the semiconductor. The induced current is directly proportional to the surface area of the cell at which the light is incident. A bare solar cell has some conducting lines made of Silver Oxide for collection of charge carriers from all the portions of the surface. These carriers are supplied to the bus bar. This is the place, from where the external terminals are connected by using copper strips. These cells are made up in different shapes and sizes like circular, square, pseudo-square, cut shaped etc. In these, pseudo-square is optimized size between circular and square to utilize most of the surface area & for less wastage in the process of shaping. The maximum conversion efficiency for laboratory devices is up to 20% but for commercial cells, it lies between 10% and 15%.

Process for Production of Solar Photo Voltaic Module:The manufacturing process for Solar cell module is not much typical but requires a careful handling since the sub-assemblies are costlier. A bare cell is expensive and hence requires a careful handling. The manufacturing process of a solar power module contains the following steps as: (a) Component Store- components and materials required for manufacturing of SPV modules are issued from component store to production. (b) Tabbing- This is the process of making terminals of a bare cell by soldering copper strips to the bus bar.



(c) Row making- A row of nine cells is made by connecting positive surfaces of one cell to the negative surface of another cell. (d) 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 Stringing. (e) String Checking- This String is checked visually for any kind of faults, which are as follows1. Reverse String 2. Dry point 3. Dry Soldering 4. Loose Connection 5. Chip ( Micro Broken ) (f) Lay Up- It is a process laminating material to the either side of the string. The laminating materials are as listed: 1. Polyester Tedlar 2. EVA (ethylene vinyl acetate) 3. String 4. EVA (ethylene vinyl acetate) 5. Top glass (Toughened glass) (g) Lamination- the above laminating materials are attached to the string on both sides by the process of lamination. This process takes place at 105 degree Celsius in laminating press. The module after Lay Up is placed in the press for 11 minutes, which is equivalent to one cycle of the press. 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. (h) Curing- This process comes after the lamination to attain the full strength of laminating materials. For this the module is placed into 140 degree Celsius temperature for 20 minutes. (i) Trimming- The resultant module from curing process has some extra laminating materials. These materials are then cut and the final module is then obtained.



(j) Electrical Inspection- This inspection is done to check the output performance of the module. (k) Channeling- Now to provide structural support to the module, channels are fixed around it. These channels prevent any damage to the module. (l) Terminal box fitting and soldering- A terminal box is also fitted for external connections and for mounting safety diodes and then the final product is cleaned and sent to the finished goods store.

Functions of Safety Diodes:The output voltage of the solar module in the day is approximately 16V-18V and it is used to charge a 12V battery. But in the night hours the output voltage of a solar module will be lower than that of battery. Hence a reverse current will flow in this condition from the battery to the solar module. Thus to prevent it, we use safety diodes which allows the flow of current in one direction only.

Fig.3 Process of production of Solar Module



PROCESS FLOW CHART FOR SPV PRODUCTION

PRODUCTION STAGE

INSPECTION STAGE

Fig.4 Process flow chart for SPV Production



Fig.5 SPV Panels on house roof

Features of SPV Cells:(a) High efficiency monocrystalline Silicon Solar cells connected in series. (b) Lamination using TEDLAR, Crane glass and EVA provides environmental protection. (c) Solar Cells laminated between UV resistant polymer (EVA) and high transmitivity toughened glass surface. (d) Rugged weather proof nylon terminal box for output connections. (e) Anodized aluminum frame provides structural support for mounting and shock resistance. (f) Manufactured to stringent quality standards and tested to withstand adverse environmental conditions.

Applications of SPV Modules:(a) The photovoltaic cells were developed at Bell Labs in 1950 primarily initially for space applications. The Hubbell telescope utilizes solar panels for its energy requirements. (b) Solar panels can power a 17 b/w TV, a radio or a fan.



(c) Some electric lighting systems provide sufficient current for up to 10 hours of lightening each evening. (d) Locally produced car batteries can provide up to 5 nights of energy for 8 watt DC fluorescent light. (e) The Mazda 929 uses solar cells to activate a fan to ventilate the car when the car is idle and parked during a sunny hot day. (f) Space Age technology: Solar cells, also known as Photo Voltaic cells were rapidly developed to provide electrical energy for space missions. (g) In Domestic lightening system, street lightening system, portable lantern, water pumping, railway signaling and lightening, etc.

AGRO DAIRY DIVISONThe electronics division kicked off its operations in 1982, the year of formation of the company and has notched up many credits in the last one and a half decade. The operations started with the Electronic Milk Tester (EMT) under technical collaboration with A/S Foss Electric of Denmark, and assembly of Electronic Milk Tester (EMT) in SKD form, from kits supplied by the collaborator, initially. The company has rapidly absorbed and assimilated the technology, successfully indigenized the product, and in response to customer requirements, designed it on micro- controller technology to suit the needs of the Indian customers. Thus, the auto-zero EMT was introduced in the market in the year 1990. The company has also successfully integrated the products into a more versatile system, developed in-house through it own developed efforts, called the Milk Collection Station.

Electronic Milk TesterDuring my training period the second division of REIL is agro dairy division, the main product of agro division is electronic milk tester, so in this section of REIL, I learned about EMT and its different sub assemblies and its working principle and testing. EMT is a simple, economical but



accurate milk fat testing instrument. It measures the fat content instantaneously on a digital read out. It does not involve the use of corrosive chemicals. It works on light scattering principle with manual homogenization. It operates on AC-mains as well as on battery with inbuilt battery charger and automatic switch over to battery in case of power failure. Several thousand small/large dairies and village Milk Collection Centers are being benefited with its use. Basic objective in the dairy development program is to increase the production of milk. Milk collection depends on prompt payment of fair and correct price to encourage producers to increase milk production. The system of payment based on quality (i.e. fat content) discourages adulteration and encourages producers to increase production of high quality milk. It is further very necessary that each sample of milk should be tested of its quality and testing should be completed within 2 to 3 hours time in order to make correct payment. Milk sample would also get spoiled if not tested immediately in the absence of facility to preserve them, especially at village level. Age old traditional GERBER method of testing milk by chemicals has many inherent drawbacks, such as human error, multistep method, handing of corrosive chemical and different types of glassware. All these add to the cost and time of milk testing. A quicker, reliable and economical method of milk has therefore become inevitable and an immediate problem to solve. In the light of some problems faced by GERBER method of testing, it was felt prudent, to evolve a system which should solve these problems. The process of fat measuring by EMT has evolved basic principle, diluents, preparation, homogenization, auto zero setting etc.



Fig.6 Electronic Milk Tester

Technical specifications of EMT: Performance Data:Measuring range 0-13% fat

120-150 samples/hour Capacity Accuracy (Sd) 0.06% for 0-5% fat 0.10% for 5-8% fat 0.20% for 8-13% fat



Repeatability (Sd)

0.03% for 0-5% fat 0.04% for 5-8% fat 0.08% for 8-13% fat

Sample Volume

0.5ml/test

Diluent Volume

6.5 ml/test

Table 1

Installation Requirements:Power Supply AC: 220-240 V (Max =10%, Min -15%) DC: 12V, 6A (Max 16V, Min 10.5V) Ambient temperature Dimensions (HxWxD) 5-45 oC 23x31x53 cm

Space Requirement Weight diluent)

60x80 cm (without 16 Kg.

Table 2



Basic principle of EMT:Electronic Milk Tester works on the photometric measurement of light scattered by the fat globules present in the milk sample. The measuring procedure follows the conventional system of dilution, mixing, homogenization and photometric measurement.

Working principle of measurement:(a) EMT is based on the photometric measurement of light scattered by the milk sample. The light is scattered by the fat globules, acting as small prisms. (b) Not only fat globules in milk contribute to light scattering, but also the proteins may affect the measurement. To eliminate their influence, it is necessary to dissolve them. EDTA solution is used for the purpose. (c) All the fat globules do not have the same size. The measuring system requires a constant fat globule size to provide a mixed relation between the amount of light scattered to the fat content. This is done by homogenizing and bringing the globule size into the range of 0.5 to 1.5 microns. (d) Light rays from a photo lamp are passed through the layer of fluid in the cuvette and are scattered according to the sample of fat globules in sample. Photocell detects and current is fed to digital readout. (e) Light rays from a photo lamp passed through the layer of fluid in the cuvette and are scattered according to the sample of fat globules in the sample. More the fat is present in the cuvette, more is the light scattered and less light passes through the cuvette. The rays that do pass through the cuvette strike a photocell, producing a current proportional to light intensity. The current is fed to a digital readout unit which gives direct fat percentage read out.



Different Sub-assembly of EMT is as follows:(a) Photometer: The photometer consists of a lamp, lamp housing and detector assembly. The detector assembly includes the cuvette and photo cell. (b) Cuvette: It is made of two hardened glass discs. One has a ground depression of 0.4 mm and the other has two small holes to provide inlet and outlet to the cuvette. (c) Photocell: It is selenium barriers / silicon detector photocell. Care should be taken not to expose this photocell to light when not in operation. (d) Lamp: 12 volts tungsten Lamp.

Sub assemblies:



Fig.7 Block diagram of EMT

(a) Cable Assembly



(b) Charging Regulator: It has two functions when battery has been discharged it limits charging current to 5 amps, and other is when battery has been fully charged and reaches 14.1D charging regulator turns off charging current entirely.

(c) Switch unit(d) Control panel: Output of power is given to measure pcb where current from photocell is led to 3 position switch to IC where current is converted to voltage. (e) Power supply: (Power PCB) this is a serial regulator with no current limit. Base current goes to ground via resistor. (f) Thermo Block: it is used for temperature control it consists of heater resistance, thermo fuse (70 degree blow), NTC, Steel coil. An NTC resistor sensor is located in a hole at rear of thermo block. Temperature control of power supply PCB contains a bridge circuit which is adjusted to balance when NTC is 50 deg Celsius bridge output is amplified and controls transistor power amplifier of heat control circuit. The output transistor and heat resistor are mounted at rear of thermo block. (g) Dispenser Unit: It consists of EDTA powder + distilled water + titrounax + antifoam. (h) Homogenizer: It uniforms fat globules solution entering and a film is made of sample. If the fat is of high amount film is thick so light is more saturated thus voltage decreases. If fat is less film is thin thus voltage decreases, (i) Photometer and its associated parts: 1. Detector assembly induces the cuvette and photocell. 2. Cuvette: it is made of 2 hardened glass discs one has 0.4mm ground discs; another has 0.4mm ground depression. 3. Photocell: Selenium barrier / Silicon detector photocell. It should not be exposed to light when the device is not in operation. 4. Lamp 12 Volt tungsten (j) Rear Panel: It consists of 12 V battery and a heat sink for cooling purpose



Preparation of Diluent:(a) Diluent is used to dilute the milk sample and dissolve the proteins. (b) Chemicals required to prepare 10 litres of diluent are as follows: 1. EDTA Sachet: 52.6 gms Containing EDTA Powder 45.0 gms Di-sodium hydroxide-7.6 gms 2. Triton-x-100 (Emulsifier): 0.5 ml (10 drops) 3. Antifoam: 0.5 ml (10 drops) (c) Procedure: take a clean 10 litre plastic container and add 1 litre clean water. Add contents of EDTA sachet, containing diluents powder for 10 litres solution. Add 0.5 ml of Triton-x-100 and 0.5 ml antifoam. Put the lid on the container and shake it until all the chemicals are dissolved, then add 9 litres clean water to prepare 10 litres solution and shake again to mix the solution.

Installation of EMT:(a) Place of installation should be such that there should be sufficient space for diluents container and battery also. Handle of EMT must be easy to reach. (b) Check 1 amp fuse in mains fuse holder and 10 amp fuse in the battery holder. (c) Connect power cables to mains. (d) Use only 12V motor car battery connect red lead of battery to + pole of battery and black lead to -pole. (e) Set selector switch at line 1, battery will now be supplied to EMT from battery. As long as main switch is at on operation, current from mains will keep the battery charged. If the power fails battery will still be able to supply enough current for several hours of operation. Set the selector switch at line, if for any reason the EMT is to be operated on mains current without a battery. (f) Prepare the diluents as described earlier.



(g) Connect one end of plastic thick pipe to INLET stub at back of EMT and attach the filter unit to other end which is placed in the diluents container. (h) Connect one end of plastic thin pipe to OUTLET stub and place the other end in waste container. (i) Place empty beaker under milk intake tube and push milk in & milk out buttons alternatively until no bubbles are seen in syringes, end by pushing milk out button.

Process of measurement:(a) Set power switch at ON. (b) Set battery switch at LINE/BATTERY (c) Fill bottle with diluents. (d) Empty bucket for waste. (e) Do not start procedure until EMT has been switched ON half an hour to one hour. (f) Setting display at 0.00 (g) Place milk beaker under milk intake (h) Push milk in, milk out. (i) Move mix beaker to mix intake. (j) Raise and lower handle 6 times. (k) Push repeat button so that display blinks. (l) Push zero buttons so that display reads 0.00 (m)Push repeat so that display doesnt blink ( one decimal ).

After deairing and zero setting, measurement can begin. First result after zero check/ zero setting should not be recorded as it will be little low. Therefore, measure the first sample after zero check twice and record only second result. Turn the milk sample gently upside down a few times. Place the sample under milk intake and fully press MILK IN button. Slowly remove the sample without touching the milk intake tube. Place clean milk under milk intake so that it fills into notch on the side of EMT. Press MIXOUT button in all the way to



dispense milk and diluents into mix beaker. Move the mix beaker to mix intake tube and position it so, that it rests in the notch. Operate the homogenizer handle up and down 3 times in a steady measurement. When the handle is pressed down the third time, let it test in bottom position and result will soon appear on the display. Empty the mix beaker completely and it is ready for the next sample.

End of measurement:Place a clean, empty mix beaker under milk intake tube and press MILK IN and MIXOUT buttons twice alternately to fill mix beaker with diluents. Place the mix beaker under mix take and operate the handle up and down six times to flush the cuvette. Switch off the EMT.

De-airing the homogenizer:Air will enter the homogenizer if the handle is raised when there is no liquid present at the mix intake tube. Place the mix beaker under milk intake tube and press MILK IN & MILK OUT buttons twice to fill the beaker with diluents. Now place the filled mix beaker under the MIX INTAKE tube and raise the handle. Loosen the bleeder screw on the top of mix intake valve. Let the handle drop by its own weight and tighten the bleeder screw again. Operate the handle three more times up and down to be sure that all air is out of system.

Features of EMT:(a) Auto zero facility (b) Performs 120-150 samples per hour. (c) Instant measurement and display of milk fat. (d) Accepts small sample volume



(e) Inexpensive method of milk testing (f) Measures upto 13% fat (g) Easy to read digital LED display. (h) Automatic switch-over to battery in case of power failure (i) Built in battery charger. (j) Runs on mains and battery both.

QUALITY ASSURANCE & ENGINEERING DEPARTMENTEvery company has a cell for checking the quality of its goods, so that the consumers can use the product without any difficulty for a long time. REIL has a department for quality assurance and control. In my training period I also gone through this department where I saw the various functions of this department include: (a) Solar module checking. (b) EMT checking.

Inward goods checking:The raw material bought by REIL for the production of EMT and Solar Module are firstly checked, if they are faulty or not. If they are faulty, they are returned otherwise forwarded to manufacturing cell. This type of checking in called inward goods checking. In this type of checking, out of a group of say 60 pieces, 5 pieces are checked randomly. If they all are found to be good, then all are passed to production department, and if not then, all pieces are checked one by one. The faulty pieces are forwarded for replacement. Subassembly Quality Control: This department also checks the quality of subassemblies, made by the raw goods by REIL.



Final Goods Inspection: After the final product is obtained; it is again checked for quality control.

SPV Checking:It has three major phases(a) Inward Goods checking: First of all, the bare cells are checked for required quality. (b) String Checking: After making string, it is checked visually, if there are any faults or not. The main faults in a string are1. Reverse String 2. Dry point 3. Dry Soldering 4. Loose Connection 5. Chip (Micro broken) (c) Electrical Inspection: This is used to check the performance of output of the module under normal working condition. This is checked using a device called sun simulator. A sun simulator generates the light of same intensity and frequencies as that of SUN and check the module under the following parameters1. Open circuit voltage. 2. Short Circuit current. 3. Maximum power. 4. Peak voltage 5. Peak Current.



6. Load Power 7. Load voltage

Technical fault finding in EMT:(a) Rear Panel Checking: All components of the rear panel are checked using a millimeter. It is a part of final quality control. Continuities of the circuit are checked.

(b) PCB calibration1. Measure PCB: PCBs are programmed as per need and requirements and fat content. REPEAT and ZERO buttons are checked for functionality. 2. Power Supply PCB: It has two operations, Temperature control and Voltage level supply (Low 5.9V to 9.9V) both are tested. 3. Charger PCB: It is checked for charging at 14.1V for a 5 ampere battery. (c) Valve Testing: There are three types of valve which are classified on the basis of the pressure at which they work. These are: 1. Red Valve: It takes diluents to dispenser unit from inlet. 2. Green Valve: Dispenser to dispenser again. 3. Blue Valve: Outlet of checked sample (waste). (d) PCB cleaning: PCBs are cleaned with the chemicals meant for the same. All the dust gets removed and PCB is ready for installation after this. (e) Temperature testing (thermo block): Temperature of the thermo block is set with the help of power PCB. Maximum Temperature: 50.1 to 50.2 degrees Celsius Minimum temperature 49.0 to 49.1 degrees Celsius. All measurements are done with the help of electronic thermometer. We insert the sensor in a hole of thermo block. (f) Mechanical testing: Mechanical connections and joints are checked. Attachments are tightened to provide strength to the machine. (g) Life test: It is done to check mechanical faults and leakage after overall testing to see how the device is working in practical situations.



(h) Dispenser test: Leakage of the milk and diluents chambers is checked. If found, dispensers are send back for repairing.

OTHER SPV PRODUCTS ProductSPV Modules Street lighting system SPV water supply system

ApplicationPower conversion (Sunlight to electricity) Village Street Lighting Village drinking water supply & land irrigation

SPV Domestic Lighting System

Village community lighting

SPV Power Packs for Battery Charging

For police check Posts & BSFcommunication sets

SPV Lantern

For providing a portable neat and clean illumination system for use in village huts, farms, work place, etc. For providing illumination at villages huts

SPV Hut Lighting System

SPV Power Station

For village electrification

Table 3



OTHER PRODUCTS MANUFACTURED OR TESTED AT R.E.I.L

AUTOMATIC MILK COLLECTION UNITThe Automatic Milk Collection Unit (AMCU) is an integrated unit, comprising of following: (a) Electronic Weighing Scale (b) Electronic Milk Tester (c) Personal Computer (d) Society Accounting & Management Software (e) Dot Matrix Printer (f) Digital Indicator (g) Uninterrupted Power Supply The system is suitable for instant weighing of milk, measurement of fat content and calculating the amount payable to the individual member based on fat and weight. This system can also be used for maintaining the complete records of the village co-operative society together with details of all transactions. This system can perform 120-150 operations in an hour. The sequence of operation require pouring of milk in weighing milk can, collection of milk samples at the time of pouring, entering the member code through keyboard, measurement of fat content, calculation of payment and printing of payment slip. Soceity Accounting And Management Software covers computerisation of the various activities of a village co-operative society. The total solution including computerization is conceived, design, developed and customized for the dairy sector.



Technical specification:Measuring Range 0-13%

Capacity Sample Volume Diluents volume

120-150 samples per hour 0.5ml/test 6.5ml/test

Table 4

Features:(a) Society management 1. Society/ member Registration 2. Member Shares 3. Milk Rates/ charts (b) Milk management 1. milk collection/local sales /dairy sale 2. milk received at dairy 3. milk payments/ daily register 4. member/shift/month/yearly/bonus reports (c) Inventory management 1. Stock register 2. Material purchase 3. Material sales (d) Accounts management 1. Trial balance 2. Day/cash/bank book



3. Ledger accounts 4. Profit & loss / balance sheet

DATA PROCESSING MILK COLLECTION UNIT (DP-MCU)Data Processor Milk Collection Unit (DP-MCU) is an integrated unit, comprising of the following: (a) DP-EMT, (b) Electronic Weighing Scale (c) Digital Indicator (d) Dot matrix printer. EMT measures the fat content of the milk. The membership codes of individual members are entered manually by keypad. The weight can be entered either manually or captured automatically. The equipment measures weight, fat content and gives the printout of transaction of milk brought in by each producer. 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. The system also facilitates storing ten days/monthly data and printing of cumulative summary as and when needed. Data processor EMT works on the principle of photometric measurement of light scattered by the fat globules present in the milk sample. The measuring procedure follows the conventional system of dilution, mixing, homogenization and photometric measurement.

Technical specification:Measuring Range Sample Volume : 0-13% : 110-130 samples per hour



Capacity Diluents volume

: :

0.5ml/test 6.5ml/test

Table 5

Features:(a) Milk testing, weighing, data processing and automation (b) Auto zero facility (c) Performs 110-130 samples per hour (d) Instant measurement and display of milk fat (e) Instant calculation of amount payable (f) Facility to feed milk weight directly through keypad in absence of weighing machine. (g) Printing facility (h) Instant transmission of datas on remote display (i) 7 segment Green LED display of 25mm height (j) Data storage upto 700 members for 30 days (k) Built in battery charger (l) Runs on mains battery both (m)Instant transmission of data ( member code, fat, weight and amount)

AUTOMATIC ELECTRONIC MILK TESTERAutomatic 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 and to ensure proper homogenization for higher fat sample. Percentage of fat content is displayed quickly and accurately on a digital read out.



Working Principle:Automatic EMT works on the photometric measurement of light scattered by the fat globules present in the milk sample. The measuring procedure follows the automated system of dilution, mixing, homogenization and photometric measurement.

Technical Specifications:Measuring range. Capacity 0-13% fat 150-180 samples/hour

Sample volume Diluents volume

0.5ml/test 6.5ml/test

Accuracy (Sd)

0.10% for 0-8% fat 0.20% for 8-13% fat

Repeatability

0.04% for 0-8% fat 0.08% for 8-13% fat

Table 6

Features of Auto EMT:(a) Auto intake of milk sample (b) Auto homogenization (c) Auto zeroing (d) Runs on mains



(e) Quick and instant read out (f) Requires small quantity of milk (g) Measures up to 13% fat (h) Performs 150Min- 180Max test per hour (i) Inexpensive method of testing (j) Process indication (k) Close correlation to accepted standard methods or measurement of milk parameters.

Fig.8 Auto EMT

MILKO SCAN MINORToday, chemical methods such as GERBER, babcock, Kjeldahl and other traditional methods are no longer the only practical low-cost solution for e.g. Fat and Protein testing needs. The MilkoScan Minor is very attractive because of its lower cost and less time used per sample. It is easy to use, rapid and has a fine performance. The results are presented to you in approximately 90 seconds and enable you to standardize milk or perform milk payment analysis on Fat and other parameters.



With MilkoScan Minor you get a simple analysis of whole range of parameters all from one sample in only one operation. It is possible to prepare a sample set on the PC before collecting results and prepare a manual sample. MlikoScan Minor is based on well known IR technology used in other Foss MilkoScans and complies with IDF standards and AOAC official methods. This makes it easy for non-skilled users to operate the instrument. Analysis of your milk and cream can take place instantly. There is no need for special sample treatment and no use of hazardous chemicals, making MilkoScan Minor very safe and inexpensive to use. Analysis of milk and cream can take place instantly. There is no need for special sample treatment and no use of hazardous chemicals is there.

Fig.9 Milcoscan Minor

MilkoScan Minor PC software :(a) Save Time- With Foss MilkoScan Minor PC software, many of the time-consuming tasks related to milk analysis can be carried out by means of an external PC. The



simplified procedures for data collection, calibration adjustment and data storage provides for greater efficiency and productivity in your daily work. (b) Data Collection- All results can automatically be collected, displayed and stored for calculation and adjustment of the basic calibrations. All results can be saved, printed and exported to other software programs. This ensures greater data security and reduces manual data entry. (c) Export and import of data- The results can be exported for use in other software programs. Measured results can be imported and used in various sample sets. Results can be exported and printed on any printer via PC. (d) Emulator- Emulator software is included in order to provide training and demonstration and for easy and fast learning of the software. (e) Compatibility- The milkoScan Minor PC software is approved to run under Windows 2000 and Windows XP with service pack 2. (f) Local Language options- German as well as English language is implemented in the PC software. (g) Sample ID-Sample ID can be entered before or after data collection. (h) Product program names- Customized product program names can be typed in. (i) Calibration Adjustment- The password protected adjustment section provide editing of referenced data, calculation of basic calibration using slope and intercept and statistic plots helping to evaluate the adjustment of calibration.

Analyzer Features:(a) Pre-calibrated for milk and cream (b) Automatic cleaning and zero setting (c) Unique Foss standard sample (d) Non-hazardous chemicals (e) Easy and cost effective. (f) Analysis of cold samples.



PC software features:(a) Automatic data collection (b) Calibration adjustment (c) Import/export of result

Parameters to be measured:(a) Fat (b) Proteins (c) Lactose (d) Total solids (e) Solids-non-fats (f) Freezing point depression (g) Simple analysis of milk composition with MilkoScan Minor.

Installation Requirements:(a) Dimensions (H x W x D) (b) Power supply (c) Performance data measuring speed (d) Measuring range (e) Protein (f) Lactose (g) Solids non-fats (h) Total solids (i) FPD (j) Repeatability (k) Purging efficiency (l) Sample volume (m) Sample temperature : 285 x 500 x 360 mm :100-240 VAC, 50-60 Hz : 40 samples per hour : Fat 0- 40% : 0 8% : 0 7% : 0 15% : 0 50% : 0.45 0.55 oC : F,P,L, TS, SnF < 0.50% rel. : >99% : < 8ml : 5 40 oC



(n) Environment temperature (o) Humidity

: 5 38 oC : 0-95% RH

BACTOSCAN FCThe BactoscanTM FC is the Ideal solution for laboratories requiring reliable, instant and accurate bacteria count in raw milk with minimum sample handling. The unique combination of technology and biochemistry combined with optimum data processing and a software platform second to none, make Bactoscan Fc a winner. The Bactoscan Fc is a true member of the Foss integrator family. The same conveyors bar code readers etc. can be used throughout the laboratory. This eases training of laboratory staff and facilities data transfer and handling. The Bactoscan FC consists of the analyzer, the PC and the basic Foss integrator software package. A number of options are available. The 100% automated Bactoscan FC employs flow cell cytometry to provide a system that counts individual bacteria cells-IBC. This gives a high accuracy compared to methods that are strongly influenced by bacterial growth requirements and by the number of single bacteria in a bacteria cluster. Analytical quality assurance a complete range of control samples and quality assurance application software offers a system for monitoring and documenting correct analyzer performance, and helps trouble shooting if need.



Fig.10 Bactoscan FC

Installation Requirements:(a) Dimensions: 85 x 260 cm (b) Space Requirements: 2 x 4.5 meters (c) Weight: 197 Kg (d) Power supply: 110-240V AC (e) Power Consumption: 50VA stop, Max 2000VA (f) Water Supply for preparation: Purified water (

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