1. Abstract: Man is an ambitious creator. He has conquered the world of science and has reached to this 21ST century. In pre-cuts of perfection, He has cared much for automation and product quality which is directly co related to electronics. In this fact developing society, electronic has come to stay as the most important branch of Engineering. Electronic devices are being used in almost all the industries for quality control and automation. They have become a fast replacement of present workers army which is engaged in processing and assembling of the factory. In this fact developing society, electronic has come to stay as the most important branch of Engineering. Electronic devices are being used in almost all the industries for quality control and automation. They have become a fast replacement of present workers army which is engaged in processing and assembling of the factory. 2. Problem statement: The objective of this project is to make a device with the help of PLC which can control automatically the devices connected with it, the PLC we are using is Siemens LOGO module, we control the street light, home appliances, Lamp Flasher, and star delta starter. The PLC helps us in automatic control of devices with its output signal; we can also provide the time delay using timers.

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3. Purpose of the Project: An engineer discovers new ideas and identifies opportunities in various sectors of national economy. He explores the possibilities of starting adventures infield of agriculture, trade, industry, transport and communication etc. An engineering project is a combination of numerous activities on the part of entrepreneurs, organizers, designers, workers and etc. The engineer is the key element in any project work and it is not possible to attain success for every engineer. An engineer should possess certain qualities and characteristics to achieve success in project or task undertaken. The characteristics which contribute to engineer’s success in his Technical competence, better judgment, intelligence, leadership, self-confidence, attitude of creativeness, honesty and emotional Stability. The purpose of this project is to save the power and save electricity with automatic control of devices with Programmable Logic Controller. 3.1.Learning Objectives: Develop a basic understanding on the following concepts: 1. To know about the Programmable Logic Control. 2. To learn the interfacing of PLC with hardware. 3. Learn about the concept of the programming software “LOGO soft! Comfort” 4. Understating about the star-Delta starter. 5. Principles of Ac circuits

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4. Project Description: In this project “Load Management System using PLC”, we use PLC for automatic Control of device and we control four devices (star-delta starter, street lights, lamp flasher, home appliances) using PLC, the function of star delta starter is to start the motor in Star connection and after some time switch to delta connection. And flasher flashes in every second with some time delay predefined in PLC. PLCs were invented in the 60/70's for the automotive manufacturing industry. Since this time, they have developed into one of the most versatile tools used for industrial automation. A working knowledge of PLCs and other microprocessor based control systems are critical to technical personnel who are staying current with technology in industry. Programmable Logic Controllers or PLC is the hub of many manufacturing processes. These microprocessor based units are used in processes as simple as boxing machines or bagging equipment to controlling and tracking sophisticated manufacturing processes. They are in virtually all new manufacturing, processing and packing equipment in one form or another. Because of their popularity in industry, it becomes increasingly more important to learn skills related to these devices.

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5. Component Details: 5.1.THE PLC: A programmable logic controller (PLC), also referred to as a programmable controller, is the name given to a type of computer commonly used in commercial and industrial control applications. PLCs differ from office computers in the types of tasks that they perform and the hardware and software they require performing these tasks. While the specific applications vary widely, all PLCs monitor inputs and other variable values, make decisions based on a stored program, and control outputs to automate a process or machine.[1]

Fig.1: Basic Application of PLC’s 5.1.1. Basic PLC Operation: The basic elements of a PLC include input modules or points, a central processing unit (CPU), output modules or points, and a programming device. The type of input modules or points used by a PLC depends upon the types of input devices used.

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Some input modules or points respond to digital inputs, also called discrete inputs, which are either on or off. Other modules or inputs respond to analog signals. These analog signals represent machine or process conditions as a range of voltage or current values. The primary function of a PLC’s input circuitry is to convert the signals provided by these various switches and sensors into logic signals that can be used by the CPU. The CPU evaluates the status of inputs, outputs, and other variables as it executes a stored program. The CPU then sends signals to update the status of outputs. Output modules convert control signals from the CPU into digital or analog values that can be used to control various output devices. The programming device is used to enter or change the PLC’s program or to monitor or change stored values. Once entered, the program and associated variables are stored in the CPU. In addition to these basic elements, a PLC system may also incorporate an operator interface device to simplify monitoring of the machine or process.[2]

INPUT

CENTRAL PROCESSING UNIT (CPU) OUTPUT MODULES

MODULES

PROGRAMMING DEVICE

OPERATOR MODULE

Fig.2: Architecture of PLC

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Fig.3 : PLC Overview In the simple example shown below, pushbuttons (sensors)

connected to PLC inputs are used to start and stop a motor output

connected to

a PLC

through a motor starter (actuator). No programming device or

operator interface is shown in this simple example.[1]

Fig.4: An Example

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5.1.2. Advantages of PLCs: PLCs not only are capable of performing the same tasks as hard-wired control, but are also capable of many more complex applications. In addition, the PLC program and electronic communication lines replace much of the interconnecting wires required by hard-wired control. Therefore, hard-wiring, though still required to connect field devices, is less intensive. This also makes correcting errors and modifying the application easier. Some of the additional advantages of PLCs are as follows:       Smaller physical size than hard-wire solutions. Easier and faster to make changes. PLCs have integrated diagnostics and override functions. Diagnostics are centrally available. Applications can be immediately documented. Applications can be duplicated faster and less expensively.

5.1.3. Siemens Modular PLCs: Siemens SIMATIC PLCs are the foundation upon which our Totally Integrated Automation (TIA) concept is based. Because the needs of end users and machine builders vary widely, SIMATIC PLCs are available as conventional modular controllers, embedded automation products, or as PC-based controllers. Modular SIMATIC controllers are optimized for control tasks and can be adapted to meet application requirements using plug-in modules for input/output (I/O), special functions, and communications.[1]

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Examples of products in this category include: LOGO, S7-200, and S7-1200 micro automation products, S7-300 and S7-400 modular system PLCs, C7 combination controller and panel, and ET 200 distributed I/O system with local intelligence.[3]

S7-200

S7-300

S7-400

ET-200 S7-1200

Logo S7-400H Fig.5: Various PLC modules
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5.1.4. The LOGO! PLC: In this project, we are working with Siemens LOGO PLC

1- Connection terminal for inputs 2- Connection terminal for outputs 3- PLC power supply terminal (24V DC/230V AC) 4- LCD screen (multi characters) 5-Keypad with 6 keys (arrows: up, down, right, left and ESC and OK keys) 6- Memory cartridge

Fig.6: LOGO! PLC

The LOGO! Expansion module: 1- Connection terminal for inputs 2- Connection terminal for outputs 3- Expansion terminal power supply 4- Visualisation LED RUN/STOP 5- PLC connection lever [2]

Fig.7: Expansion Module
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5.1.5. TECHNICAL DATA

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5.1.6. PLC HARDWARE:  Power Supply - This can be built into the PLC or be an external unit. Common voltage levels required by the PLC (with and without the power supply) are24Vdc, 120Vac, 220V AC.  CPU (Central Processing Unit) - This is a computer where ladder logic is stored and processed.  I/O (Input/Output) - A number of input/output terminals must be provided so that the PLC can monitor the process and initiate actions.  Input - In smaller PLCs the inputs are normally built in and are specified when purchasing the PLC. For larger PLCs the inputs are purchased as modules, or cards, with 8 or 16 inputs of the same type on each card.  PLC Operation: All PLCs have four basic stages of operations that are repeated many times per second. Initially when turned on the first time it will check its own hardware and software for faults. If there are no problems it will copy all the input and copy their values into memory, this is called the input scan. Using only the memory copy of the inputs the ladder logic program will be solved once, this is called the logic scan. While solving the ladder logic the output values are only changed in temporary memory. When the ladder scan is done the outputs will updated using the temporary values in memory, this is called the output scan. The PLC now restarts the process by starting a self-check for faults. This process typically repeats 10 to 100 times per second.[3]  Self-Test - Checks to see if all cards error free, reset watch-dog timer, etc. (A watchdog timer will cause an error, and shut down the PLC if not reset within a short period of time - this would indicate that the ladder logic is not being scanned normally).

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

Input Scan - Reads input values from the chips in the input cards, and copies their values to memory. This makes the PLC operation faster, and avoids cases where an input changes from the start to the end of the program (e.g., an emergency stop). There are special PLC functions that read the inputs directly, and avoid the input tables.



Logic Solve/Scan - Based on the input table in memory, the program is executed 1step at a time, and outputs are updated. This is the focus of the later sections.



Output Scan - The output tables is copied from memory to the output chips. These chips then drive the output devices.



Central processor unit (CPU): The central processor unit (CPU) is a microprocessor system that contains the system memory and is the PLC’s decision making unit. The CPU monitors inputs, outputs, and other variables and makes decisions based on instructions held in its program memory.

Fig.8: A Central Processing Unit of PLC

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

Sensors: Sensors are devices that convert a physical condition into an electrical signal for use by a controller, such as a PLC. Sensors are connected to the input of a PLC. A pushbutton is one example of a sensor that is often connected to a PLC input. An electrical signal indicating the condition (open or closed) of the pushbutton contacts is sent from the pushbutton to the PLC.



Actuators: Actuators are devices that convert an electrical signal from a controller, such as a PLC, into a physical condition. Actuators are connected to the PLC output. A motor starter is one example of an actuator that is often connected to a PLC output. Depending on the status of the PLC output, the motor starter either provides power to the motor or prevents power from flowing to the motor.[2] 5.1.7. Programming of a PLC: A program consists of instructions that accomplish specific tasks. The degree of complexity of a PLC program depends upon the complexity of the application, the number and type of input and output devices, and the types of instructions used. Ladder Logic Programming: Ladder logic (LAD) is one programming language used with PLCs. Ladder logic incorporates programming functions that are graphically displayed to resemble symbols used in hard-wired control diagrams. The left vertical line of a ladder logic diagram represents the power or energized conductor. The output coil instruction represents the neutral or return path of the circuit. The right vertical line, which represents the return path on a hard-wired control line diagram, is omitted. Ladder logic diagrams are read from left-to-right and top-to-bottom.

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While ladder logic programs are still common, there are many Function Block Diagrams other ways to program PLCs. Two other common examples are statement list and function block diagrams.

Fig.9: Ladder logic

Statement list (STL): Statement list (STL) instructions include an operation and an operand. The operation to be performed is shown on the left. The operand, the item to be operated on, is shown on the right. Function block diagrams (FBD): Function block diagrams include rectangular

functions with inputs shown on the left side of the rectangle and outputs shown on the right side. Other languages are Flowchart based design and Instruction list programming.

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Number Systems: Because a PLC is a computer, it stores information in the form of on or off conditions (1 or 0), referred to as bits. Sometimes bits are used individually and sometimes they are used to represent numerical values. Understanding how these bits can be used to represent numerical values requires an understanding of the binary number system.[3] The number system includes Binary system, Decimal System, Hexadecimal system. Software: Software is the name given to computer instructions, regardless of the programming language. Essentially, software includes the instructions or programs that direct hardware. The software used to programming with LOGO is Logo Soft Comfort. The LOGO PLC is used for this purpose because of its ease of use and small scale application. The items shown in the following illustration are needed to create or change a logo PLC program. The program is created using LOGO soft programming software, which runs on a Windows-based personal computer (Win2000, Windows XP, and higher operating system). A special cable is needed when a personal computer is used as a programming device. Two versions of this cable are available. One version, called an PPI Multi-Master Cable, connects a personal computer’s RS-232 interface to the PLC’s RS-485 connector. The other version, called a USB/PPI Multi- Master Cable, connects a personal computer’s USB interface to the PLC’s RS-485 connector. [2]

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Fig.10: Interfacing the PLC with PC by using software

5.1.8. Connections of PLC: The SIEMENS LOGO! PLC as well as expansions is designed for symmetrical DIN-rail mounting. The whole set may be locked or unlocked with a hook. The connections for logo PLC are:

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Inputs: P1= Power supply P2= power supply

Outputs: Q1 = main contactor, street light, home appliances Q2 = delta contactor Q3 = Star contactor Q4 = Lamp Flasher

Fig.11: Connections of a PLC

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5.1.9. Programme Upload or Reloading Procedure: To copy a Programme from the cartridge into the PLC, proceed as follows: 1) Plug the Programme cartridge in. 2) Activate the programming mode of the PLC (ESC / >Stop).

Fig.12: logo PLC LCD 3) Move ">" on ’Card’: Key ▼ or ▲. 4) Press OK. You access transfer menu. 5) Move ">" on ’Card _ LOGO!’ Key ▼ or ▲. 6) Press OK The PLC downloads the Programme from the cartridge. When downloading into the LOGO! PLC is over; the menu is displayed on screen. We can set the parameters of the Programme using logo keypad with six keys.

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5.1.10. LOGO Soft Comfort: The programming is mainly employed is Ladder logic programming, PLC ladder logic consists of a commonly used set of symbols that represent instructions. Understanding these basic symbols is essential to understanding PLC operation. Contacts: One of the most confusing aspects of PLC programming for first-time users is the relationship between the device that controls a status bit and the programming function that uses a status bit. Two of the most common programming functions are the normally open (NO) contact and the normally closed (NC) contact. Symbolically, power flows through these contacts when they are closed. The normally open contact (NO) is closed when the input or output status bit controlling the contact is 1.The normally closed contact (NC) is closed when the input or output status bit controlling the contact is 0.

NO (Normally open)

NC (Normally Closed)

Coils: Coils represent relays that are energized when power flows to them. When a coil is energized, it causes a corresponding output to turn on by changing the state of the status bit controlling that output to 1. That same output status bit may be used to control normally open and normally closed contacts elsewhere in the program. [1]

( )

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Boxes: Boxes represent various instructions or functions that are executed when power flows to the box. Typical box functions include timers, counters, and math operations.

Fig.13: logo soft comfort software screen

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A simple Programme in ladder logic to control the 5 lights to blink continuously in evenodd manner in logo soft is as shown below:

Fig.14: A simple Programme in Ladder logic The vertical red line in left side is called power bus, and I1 stands for input switch, and Q1-Q5 are called coils, T001 or T002 is called timers and its open contacts, and M1 is a flag which is high in four seconds, the time delay provided with timer is 2 seconds, and Q2, Q4 in the first row is called relay coils for coil 2 and 4.

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The same program in FBD program is as shown:

Fig.15: A simple Programme in FBD logic

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6. POWER CONTACTOR: When a relay is used to switch a large amount of electrical power through its contacts, it is designated by a special name: contactor. Contactors typically have multiple contacts, and those contacts are usually (but not always) normally-open, so that power to the load is shut off when the coil is deenergized. Perhaps the most common industrial use for contactors is the control of electric motors. The top three contacts switch the respective phases of the incoming 3-phase AC power, typically at least Fig.16: A power Contactor 480 Volts for motors 1 horsepower or greater.

Fig.17: A Schematic of Power Contactor

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The lowest contact is an ”auxiliary” contact which has a current rating much lower than that of the large motor power contacts, but is actuated by the same armature as the power contacts. The auxiliary contact is often used in a relay logic circuit, or for some other part of the motor control scheme, typically switching 120 Volt AC power instead of the motor voltage. One contactor may have several auxiliary contacts, either normally-open or normally-closed, if required. [4] The three “opposed-question-mark” shaped devices in series with each phase going to the motor are called overload heaters. Each “heater” element is a low-resistance strip of metal intended to heat up as the motor draws current. If the temperature of any of these heater elements reaches a critical point (equivalent to a moderate overloading of the motor), a normally closed switch contact (not shown in the diagram) will spring open. This normally-closed contact is usually connected in series with the relay coil, so that when it opens the relay will automatically de-energize, thereby shutting off power to the motor. We will see more of this overload protection wiring in the next chapter. Overload heaters are intended to provide overcurrent. Description: Protection for large electric motors, unlike circuit breakers and fuses which serve the primary purpose of providing overcurrent protection for power conductors. Overload heater function is often misunderstood. They are not fuses; that is, it is not their function to burn open and directly breaks the circuit as a fuse is designed to do. Rather, overload heaters are designed to thermally mimic the heating characteristic of the particular electric motor to be protected.

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All motors have thermal characteristics, including the amount of heat energy generated by resistive dissipation (I2R), the thermal transfer characteristics of heat ”conducted” to the cooling medium through the metal frame of the motor, the physical mass and specific heat of the materials constituting the motor, etc. These characteristics are mimicked by the overload heater on a miniature scale: when the motor heats up toward its critical

temperature, so will the heater toward its critical temperature, ideally at the same rate and approach curve. Thus, the overload contact, in sensing heater temperature with a thermo mechanical mechanism, will sense an analogue of the real motor. If the overload contact trips due to

excessive heater temperature, it will be an indication that the real motor has reached its critical temperature (or, would have done so in a short while). Fig.18: A Typical Power Contactor

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After tripping, the heaters are supposed to cool down at the same rate and approach curve as the real motor, so that they indicate an accurate proportion of the motor’s thermal condition, and will not allow power to be re-applied until the motor is truly ready for start-up again. Shown here is a contactor for a three-phase electric motor, installed on a panel as part of an electrical control system at a municipal water treatment plant. Three-phase, 480 volt AC power comes in to the three normally-open contacts at the top of the contactor via screw terminals labeled ”L1,” ”L2,” and ”L3” (The ”L2” terminal is hidden behind a square-shaped ”snubber” circuit connected across the contactor’s coil terminals). Power to the motor exits the overload heater assembly at the bottom of this device via screw terminals labeled”T1,” ”T2,” and”T3.” The overload heater units themselves are black, square-shaped blocks with the label”W34,” indicating a particular thermal response for a certain horsepower and temperature rating of electric motor. If an electric motor of differing power and/or temperature ratings were to be substituted for the one presently in service, the overload heater units would have to be replaced with units having a thermal response suitable for the new motor. The motor manufacturer can provide information on the appropriate heater units to use. A white pushbutton located between the ”T1” and ”T2” line heaters serves as a way to manually re-set the normallyclosed switch contact back to its normal state after having been tripped by excessive heater temperature. Wire connections to the “overload” switch contact may be seen at the lower-right of the photograph, near a label reading “NC” (normally-closed). On this particular overload unit, a small ”window” with the label ”Tripped” indicates a tripped condition by means of a colored flag. In this photograph, there is no “tripped” condition, and the indicator appears clear. [4]

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Resources Needed: S.No. Equipment’s name Rating Manufacturer Quantity Cost per unit 12430 2150 550 65 8 12 16 12 12 12 12 12 .50 350 150 1500 15 8 4500 Total cost 12430 2150 1650 65 32 12 64 12 24 120 120 120 10 350 150 1500 45 8 4500 Rs.23362

1 2 3 4 5 6 7 8 9 10. 11. 12. 13. 14. 15. 16. 17. 18. 19.

PLC Logo Soft AC Contactor Din-rail-mounting Four contact switch Socket Lamp Lamp Lamp Green Wire Red Wire Blue Wire Screws Wooden Board Poster Siemens cable Bulb Holder Plug Language learning Total

LOGO Software 330cm 230V 230V 230V 100W 5W 10 meter 10 meter 10 meter 6mm

Siemens Siemens Andeli group

1 1 3 1 4

Ikon Anchor Surya Philips Havells Havells Havells

1 4 1 2 1 1 1 20

Jain Plywood Raj arts Ltd. PIP 230V 230V Siemens Ikon

1 1 1 3 1

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7. Assembling of the Project: Before we begin constructing the Load Management System using PLC, we will need to locate a clean, well-lit worktable or workbench. Next we will gather a small 25–30-W pencil tipped soldering iron, a length of 60/40 tin-lead solder, and a pair of end-cutters and we will begin constructing the project. Now locate the schematic diagram of PLC and parts layout diagram along with all of the components needed to build the project.

Fig.19: Ply Board of 100×100×30Cm First we check that the entire component is working correctly or not, finally we are ready to begin assembling the project, so let’s get started. The prototype project was

constructed on a ply board of 100×100×30 cm and pastes the poster of Project prototype on it with help of synthetic resin adhesive and for this purpose, we use a small quantity of water mixed with adhesive, and cover the whole ply with the poster.

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Now go ahead and locate where contactors are placed on the Ply Board and put the Dinrail-mount and make it tight with help of Screws in mid of the rail. Now place the contactor on it and put some pressure on it, check it to set it properly, Now take a look for wires whose first color band is red, green, and blue for the three phases of the supply, From the project we will notice that yellow is represented by the green wire, and the black wire is used for Neutral.

Green Wire

Red wire

Black wire

Now take the connections from the contactors into a panel strip into the back side of the ply board, the L1, L3,L5 is for the three phases R,Y,B. and take some wires and make the connections from the lines to the strip, and make all the connections for the three phases, it is noticed that in star contactor, the 3 contacts are shorted, and output is connected threw the three phases R,Y,B. and in delta contactor, the R1 is connected to the terminal B2, and R2 is connected to Y2 and Y1 is connected to B1 and make sure that the wires tight so that no wire is in contact with the other one. The holes for the wire are making with help of drill machine, and the all equipment’s used in this project is shown on the next page.

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1

2

3 3

4 6

5

8
2

4 7
2

9

10

11

30

14

12

13

15

16

17

19

18

Fig.20: Components used in this project (directly or indirectly)

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The component details are: 1. Screw 2. Wire cutter 3. Wire cutter 4. Soldering machine 15. Drills 5. Soldering iron 6. Soldering paste 7. Drill machine 8. Bulb holder 9. Synthetic Resin Adhesive 10. Wooden cutter Now come to the street light mounting, for that first we make all the holes carefully on the Ply Board and place the bulb in it, and also place a switch for controlling it, these lights are working on single phase supply, so we need one phase and one neutral wire supply for it, we combined all the phase wire and neutral wire separately and take connections to the strip for connecting it parallel to the main conductor supply of the star delta starter. 7.1. About the Star-Delta Starter: Star-Delta method of starting of cage induction motors is based upon the principal that with 3 windings connected in star, the voltage across each winding is 1/√3 i.e., 57.7 % of the line to line voltage whereas the same winding connected in delta will have full line- to line voltage across each. 16. Wire cutter 17. Screw driver 18. Din-Rail mounting 19. Lamp 11. Wire cutter 12. Socket 13. 4-contact Switch 14. Plug

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The star-delta starter connects the three stator windings in star across the rated supply voltage at the starting instant. After the motor attains speed the same windings, through a change over switch, are reconnected n delta across the same supply voltage. Since at starting instant, the stator windings are connected in star, so voltage across each phase winding is reduced to 1/√3 of line voltage and, therefore, starting current per phase becomes equal to Isc /√3. Starting line current by connecting the stator windings in star at the starting instant starting motor current per phase= Isc /√3. Starting line current by direct switching with stator windings connected in delta=√3 I Therefore, Line current with star delta starting Line current with direct switching = Isc / √3 = √3 I 1 3

Hence by star-delta starting line current is reduced to one third of line current with direct switching. Starting torque, Tst = Tf (Ist / If) sf = Tf [Isc/√3/If]2 sf = 1/3 Tf (Isc/ If)2 sf Hence with star- delta switching, the starting torque is also reduced to one-third of starting torque obtained with direct switching. This method of starting of cage motors is simple, cheap, effective and efficient since no power is lost in auxiliary components. This method is also suitable for high inertia and long acceleration loads. This method needs a motor to be delta- connected for normal operation and all the six terminals of the 3-phase stator windings are to be brought out. The reduction in voltage is fixed and starting torque is also low.

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So, this method is limited to application where high starting torque is not the essential requirement e.g. machine tools, pumps, motor generator sets etc. This method is unsuitable for line voltage exceeding 3,000 V, because of excess number of stator turns required for delta connection. Such starters are employed for starting 3-phase squirrel cage induction motors of rating between 4 and 20 KW. 7.2. Precaution with Star-Delta Starting: The initial current flowing when the motor is started in star is 57.7 % of the short- circuit current in delta together with a transient in each phase. The transient currents decay rapidly but the steady state is not reached until the motor has attained 70 percent of its

synchronous speed. The changeover from star to delta

connection should not be made until the motor attains about 90 Fig.21: Star Delta Starter

percent of synchronous speed, otherwise there will be a current surge considerably greater than full- load current which may even be greater than the standstill current with star- connection.

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Fig. 22: Logo PLC Module Technical Details 7.3. Application of PLC:

 SCADA (Supervisory Control And Data Acquisition)  Energy saving VFD  Cement plants  Automation and control industry  Load management system  Industries

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Requirement of PLC Increase Productivity & Fine Quality Control

Advantages of PLC Ability to interface / communicate with Computers Field Programming possible

Reduce Human Interfere & High Speed of Operation Energy Saving & Power Factor improvement Most Economical, Smallest feature, Rugged, Flexibility, Easy to use Real Time Monitoring

Simple Programming, Smaller Size.

Reliable components make these likely to operate for years before failure. High Reliability Computational abilities allow more sophisticated control. Flexible and reapplied to control other systems quickly and easily. Cost effective for controlling complex systems Economical in Long Term Easy Expandability (Due to Modular Design). Rugged Construction - Can operate in Extremely harsh field conditions

Historical data for Network Analysis Adequate response to customer query

Improve Information Availability

Better visibility Real Time Events Monitoring Supervisory process Control Easy Maintenance for Machinery

Table 1: Requirement and Advantage of Programmable Logic Controller

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After completing the circuit for the street light, we make the circuit for lighting i.e. flasher; in this we provide a time delay of 1 sec. to lamp circuit for blink and off for next one second, for this we also need parallel connections so take connection parallel and connect to the strip, then for the controlling of the circuit, we connect this to the PLC output 4, which takes lighting Now come to the last circuit of Home appliance control, for this we need a lamp and one socket for controlling of the device we are connecting to it. So make the connections for it and take them it to the panel strip and connect it to the main conductor of star delta starter for supply. Fig.23: Multimeter for checking the short-circuit control for the

Now connections part of the circuit is completed and we inspect the PC board for possible “cold” solder joints and “short” circuits with help of multi meter. If any of

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the solder joints look dull, dark, or blobby, then you should remove the solder with a solder sucker or a solder wick and then resolder the joint all over again. Now we will inspect the Ply board for possible short circuits. Now we are ready to connect the PLC controller to the supply line, and apply power to the project; and begin testing of the circuit.[5] 8. Testing of the Project: Once the PLC Controller has been installed on the ply board and connected to the power supply, we will be ready to begin testing the PLC Controller circuit. Now the PLC is connected to hardware interfacing unit now waiting for the Programme load to the PLC. Now switch on the star delta starter, we see that in the starting, the main contactor and star contactor are on for the first 10 Second, now for a short time both the contactors are off and after that the main contactor and delta contactor are on and the motor is in this state for rest of the time. Now switch on the street light switch and home appliance switch, they are working properly or not, and now switch on the lighting switch and see that the lamp is blinking properly with the time delay of 1 second. The testing of the project “load management system” is completed and the circuit is working properly.

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Conclusion

Maintaining the competitive edge by using new technologies to stay ahead of time is the basic necessity for any industry. There is constant pressure to save time and money at every stage of the process, from planning and commissioning through to operation. Switching and controlling play a central part in this process. they must be simple and intelligent; simple in operation and intelligent in implementing the many options that are expected of an application with vision. The use of a PLC completely eliminates human error where switching-over process could not be furnished with perfection due to human factor involved in it. The high storage capacity and efficient use of memory create a host of benefits and excellent functionality. Operation could not be easier, thanks to the LOGO! Soft Comfort software. Program generation, project simulation and documentation are all performed by means of drag & drop techniques for an unparalleled level of convenience. The time and cost requirements are highly reduced by the use of Logo. Hence, automation technique employed in this project makes the process easier, reliable, and comfortable and a handsome experience.

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REFERENCE

1. http://www.siemens.com/automation 2. http://www.siemens.com /stepprogramme/plc_intro.pdf 3. http://www.siemens.com /stepprogramme/basics of plc.pdf 4. http://www.siemens.com/automationseries/LOGO!softcomfort 5. http://en.wikipedia.org/wiki/contactor 6. http://www.scribd.com/25772845.pdf 7. http://www.kpsec.freeuk.com/index.htm

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