automatic phase changer in three phase supply

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AUTOMATIC PHASE CHANGER IN 3 PHASE SUPPLY

A Project Report

Submitted in partial fulfillment for the award of the degree of

BACHELOR OF TECHNOLOGYIn

Electrical & Electronics Engineering(IV th SEMESTER)

2014 Batch

UNIVERSITY OF CALICUTBy

ADARSH K SASI (EKAOEEE001)

AMALJO JOJU E (EKAOEEE005)

ATHUL KAMAL (EKAOEEE012)

LINSON PAULSON (EKAOEEE041)

EDUCATION IS DEDICATION

SAHRDAYA COLLEGE OF ENGINEERING AND TECHNOLOGY KODAKARA, THRISSUR

NOVEMBER 2015

Department of EEE, SCET, KODAKARA Page 1

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DEPARTMENT OF ELECTRICAL& ELECTRONICS ENGG.

SAHRDAYA COLLEGE OF ENGINEERING AND TECHNOLOGY KODAKARA, THRISSUR

EDUCATION IS DEDICATION

BONAFIDE CERTIFICATE

This is to certify that the project report titled “AUTOMATIC PHASE CHANGER

IN 3 PHASE SUPPLY ” is the bonafide work of “ADARSH K SASI

(EKAOEEE001),AMALJO JOJU E(EKAOEEE005),ATHUL KAMAL

(EKAOEEE012),LINSON PAULSON (EKAOEEE041)” during our IV semester

in partial fulfillment of the requirements of the University of Calicut, under our

supervision.

PROJECT GUIDE COORDINATOR HEAD OF THE DEPARTMENT

Mrs. Sreelakshmi Suresh Mr. Madhujith Mrs. Jitha Joseph

Kodakara

15-10-2015


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ACKNOWLEDGEMENT

We hereby acknowledge our sincere gratitude to all persons who have helped us

in completing our project. We are highly grateful to Mr. Madhujith who happens to be

our project coordinator for his constant support and encouragement.

We are greatly indebted to our project guide for her valuable guidance in this

endeavor.

We are thankful to all the nonteaching staff for providing sufficient lab facilities

and our classmates for their encouragement and cooperation without which our project

would not have been possible.

Above all, we thank Lord Almighty for providing us with the courage and confidence to

take up this project.


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ABSTRACT

In most companies, Industrial, commercial and even domestic are dependent on

public power supply which have erratic supply such as phase failure, phase imbalances

or total power failure due to one or more technical problem in power generation,

transmission or distribution. Hence, there is need for automation of phase change during

phase failure or total power failure in order to safe guard consumer appliances from

epileptic power supply.

In most cases, many manufacturing companies, be it domestic or industrial,

which employ single phase equipment for its operation sometimes experience challenges

during unbalance voltages, overloads and under-voltages, in power supply, much time

would be required in the process of manual change over. This means that time and the

process needed for the phase change may cause serious damages to machines and even

the products, hence, there is need for automatic phase switching system.

In a case where a single phase public utility prepaid meter is operated with a

single phase power supply unit and there is phase failure from the public utility power

supply, the prepaid meter will stop reading. At this point if the phase is not manually

changed, the single phase prepaid meter will stop reading. That is to say someone needs

to be present always to make the changes at any point in time. But to overcome these

protocols, automatic systems need to be used.

The system is basically designed to select between the three phases at reasonable

speed, and also address phase imbalances with respect to loads. This means automatic

switching between the three phases and output only singlephase. In other words, the

switching consideration demonstrates the real and practical situation for mainly

domestic, moderate industrial advanced needs.


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CONTENTS

ACKNOWLEDGEMENT..........................................................................................3

ABSTRACT...............................................................................................................4

1. INTRODUCTION................................................................................6

2. BLOCK DIAGRAM............................................................................8

3. HARDWARE DESCRIPTION...........................................................9

3.1 CIRCUIT DIAGRAM...........................................................10

3.2 COMPONENTS AND THEIR DESCRIPTION..................13

3.3 COST ANALYSIS................................................................24

4. CIRCUIT DESIGN............................................................................25

4.1 DESIGN OF ASTABLEMULTIVIBRATOR....................26

5. WORKING..........................................................................................28

6. CONCLUSION...................................................................................30

6.1FEATURES.............................................................................30

6.2 LIMITATIONS......................................................................31

ANNEXURES..........................................................................................................32

BIBLIOGRAPHY....................................................................................................63


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1. INTRODUCTION

The basic idea for the development of the project is to provide supply to the single phase

load if any of the phases, out of the 3 phases misses. The circuit will automatically

switch to next phase while one phase is misses.Design and construction of an automatic

change over switch which would solve the problem of manpower and electric hazard.

In night time or during lightning we have not taken care of this system.

In most cases, many manufacturing companies, be it domestic or industrial,

which employ single phase equipment for its operation sometimes experience challenges

during unbalance voltages, overloads and under-voltages, in power supply, much time

would be required in the process of manual change over. This means that time and the

process needed for the phase change may cause serious damages to machines and even

the products, hence, there is need for automatic phase switching system.

In a case where a single phase public utility prepaid meter is operated with a

single phase power supply unit and there is phase failure from the public utility power

supply, the prepaid meter will stop reading. At this point if the phase is not manually

changed, the single phase prepaid meter will stop reading. That is to say someone needs

to be present always to make the changes at any point in time. But to overcome these

protocols, automatic systems need to be used.

Phase ChangerFig. 1.1 shows the basic circuit of a phase changer. In the supply section we are

connecting the three phases from the transmission line (R,Y,B). There are three switches

available in the system between each phases. There is an option to feed the loads in a

phase by another phase. If any one or two phase is missing we can feed the loads in that

corresponding phase by any of the available phase. In Manuel system the rotatable

switch


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is rotating and make it short. So there is someone required to do it. But in some

conditions it may difficult. So the automatic phase changer will do the work it’s self.

There is a system to check whether the phase is available or not. According to the

conditions it will automatically switches between the phases.

Fig 1.1


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2. BLOCK DIAGRAM

Fig 2.1

Figure 2.1 shows the block diagram representation of the Automatic Phase

changer. There is transformer block consist of 3 transformers in order to step-down the

230V in each phase into 12V. Using rectification block we are rectifying each phase

voltage into DC voltages. Optocoupler is an isolator which is used to isolate the digital

circuit from its left side circuit. There is an anti-shorting system to avoid the shorting

conditions by using delay circuit. There is a 3-contact relay through which the

connection is given to the single phase loads. The phase changing relay system is used to

changing the phases according to the instructions get from the digital circuit.


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3.HARDWARE DESCRIPTION

3.1 CIRCUIT DIAGRAM

Fig. 3.1 circuit diagram

Figure 3.1 shows the circuit diagram of the Automatic Phase changer.


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Fig. 3.1 Relay Connection Diagram


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3.1.1 PCB LAYOUT

A Printed Circuit Board mechanically supports and electrically connects electronic

components using conductive tracks, pads and other features etched from copper sheets

laminated onto a non-conductive substrate. PCBs can be single sided (one copper layer),

double sides (two copper layers) or multi-layer. Conductors on different layers are

connected with plated-through holes called vias. Advanced PCBs may contain

components - capacitors, resistors or active devices - embedded in the substrate.

Printed circuit boards are used in all but the simplest electronic products. Alternatives to

PCBs include wire wrap and point-to-point construction. PCBs require the additional

design effort to lay out the circuit but manufacturing and assembly can be automated.

Manufacturing circuits with PCBs is cheaper and faster than with other wiring methods

as component are mounted and wired with one single part. Furthermore, operator wiring

errors are eliminated.

PCB DESIGN PROCEDURE

Prepare the PCB layout of the circuit using gEDA software

Take the print out of PCB layout

Cut the copper clad sheet in proper dimension and wash it.

Trace the PCB layout on the copper clad sheet

Prepare the ferric chloride solution.

Dip the PCB in to ferric chloride solution for etching non printed surfaces.

Wash cleanly with detergents.

Drill the holes in necessary positions.


http://en.wikipedia.org/wiki/Point-to-point_construction

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

http://en.wikipedia.org/wiki/Via_(electronics)

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

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

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

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

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

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Fig 3.1.1(a)


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3.2 COMPONENTS AND THEIR DESCRIPTIONS

Components used:

Semiconductors

IC1: NE555 TIMER

IC2: 74LS04 NOT GATE

IC3: 74LS11 3 i/p AND GATE

IC4: HCF4075B 3 i/p OR GATE

IC5: ULN2003A RELAY DRIVER IC

IC6: MCT2E OPTOCOUPLER

T1: BC557 PNP transistor

T2: BC547 NPN transistor

D1-D16: 1N4007 Rectifier Diode

LED1: RED LED

LED2: YELLOW LED

LED3: GREEN LED

Resistors (all ¼watt,+/- 5% carbon)

VR1: 15 kilo ohm preset

Capacitors

1000 microfarad, 25V electrolytic




0.01 microfarad ceramic disc

Miscellaneous

230V AC primary to 12V, 500mA secondary transformer

RELAY 1 - 5 : 12V, 200 ohm, 1c/o relay

RELAY 6 : 12V, 250 ohm, 4c/o 5 A relay


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3.2.1 555 Timer IC

Fig. 3.2.1(a) Internal diagram of IC 555 fig 3.2.1(b)

Figure 3.2(a) shows the internal diagram of the NE555 timer IC.The 555 timer

IC is an integrated circuit (chip) used in a variety of timer, pulse generation, and

oscillator applications. The 555 can be used to provide time delays, as an oscillator, and

as a flip-flop element. Derivatives provide up to four timing circuits in one package.

Introduced in 1972 by Signetics, the 555 is still in widespread use, thanks to its ease of

use, low price, and good stability. It is now made by many companies in the original

bipolar and also in low-power CMOS types. As of 2003, it was estimated that 1 billion

units are manufactured every year.

Design

The IC was designed in 1971 by Hans Camenzind under contract to Signetics, which

was later acquired by Philips.

Depending on the manufacturer, the standard 555 package includes 25 transistors, 2

diodes and 15 resistors on a silicon chip installed in an 8-pin mini dual-in-line package

(DIP-8). Variants available include the 556 (a 14-pin DIP combining two 555s on one

chip), and the two 558 & 559s (both a 16-pin DIP combining four slightly modified 555s


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with DIS & THR connected internally, and TR is falling edge sensitive instead of level

sensitive).

The NE555 parts were commercial temperature range, 0 °C to +70 °C, and the SE555

part number designated the military temperature range, −55 °C to +125 °C. These were

available in both high-reliability metal can (T package) and inexpensive epoxy plastic (V

package) packages. Thus the full part numbers were NE555V, NE555T, SE555V, and

SE555T. It has been hypothesized that the 555 got its name from the three 5 kΩ resistors

used within, but Hans Camenzind has stated that the number was arbitrary.

Low-power versions of the 555 are also available, such as the 7555 and CMOS TLC555.

The 7555 is designed to cause less supply noise than the classic 555 and the

manufacturer claims that it usually does not require a "control" capacitor and in many

cases does not require a decoupling capacitor on the power supply. Such a practice

should nevertheless be avoided, because noise produced by the timer or variation in

power supply voltage might interfere with other parts of a circuit or influence its

threshold voltages. Figure 3.3 shows the pin diagram of NE555 timer IC and table 3.1

gives the pin description.

Fig. 3.3 pin diagram


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Pin Name Purpose

1 GND Ground reference voltage, low level (0 V)

2 TRIGThe OUT pin goes high and a timing interval starts when this input falls

below 1/2 of CTRL voltage (which is typically 1/3 of VCC, when CTRL is open).

3 OUT This output is driven to approximately 1.7V below +VCC or GND.

4 RESETA timing interval may be reset by driving this input to GND, but the timing

does not begin again until RESET rises above approximately 0.7 volts. Overrides TRIG which overrides THR.

5 CTRL Provides "control" access to the internal voltage divider (by default, 2/3 VCC).

6 THR The timing (OUT high) interval ends when the voltage at THR is greater than that at CTRL.

7 DIS Open collector output which may discharge a capacitor between intervals. In phase with output.

8 VCCPositive supply voltage, which is usually between 3 and 15 V depending on

the variation.Table 3.1

Modes of Operation

The 555 has three operating modes:

Monostable mode: In this mode, the 555 functions as a "one-shot" pulse

generator. Applications include timers, missing pulse detection, bouncefree

switches, touch switches, frequency divider, capacitance measurement, pulse-

width modulation (PWM) and so on.

Astable (free-running) mode: The 555 can operate as an oscillator. Uses include

LED and lamp flashers, pulse generation, logic clocks, tone generation, security

alarms, pulse position modulation and so on. The 555 can be used as a simple

ADC, converting an analog value to a pulse length. Eg: selecting a thermistor as

timing resistor allows the use of the 555 in a temperature sensor: the period of

the output pulse is determined by the temperature. The use of a microprocessor

based circuit can then convert the pulse period to temperature, linearize it and

even provide calibration means.

Bistable mode or Schmitt trigger: The 555 can operate as a flip-flop, if the DIS

pin is not connected and no capacitor is used. Uses include bounce-free latched switches.

3.2.2 74LS04 NOT GATE


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Fig 3.2.2(a) Fig 3.2.2(b)

This device contains six independent gates each of whichperforms the logic INVERT

function. It is used in the circuit to produce R’, Y’ and B’.Figure 3.2.2(a) shows the

internal diagram of the 74LS04. An inverter circuit outputs a voltage representing the

opposite logic-level to its input. Its main function is to invert the input signal applied. If

the applied input is low then the output becomes high and vice versa.The hex inverter is

an integrated circuit that contains six (hexa-) inverters. For example, the 7404 TTL chip

which has 14 pins and the 4049 CMOS chip which has 16 pins, 2 of which are used for

power/referencing, and 12 of which are used by the inputs and outputs of the six

inverters (the 4049 has 2 pins with no connection)NOT gates are simply inverters. They

simply invert the input logic for the output. Here we are going to use 74LS04 IC for

demonstration. This IC has 6 NOT gates in it.


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3.2.3 74LS11 AND GATE IC

Fig 3.2.3(a) Fig 3.2.3(b)

This IC consists of 3 independent AND gates. A Logic AND Gate is a type of digital

logic gate that has an output which is normally at logic level “0” and only goes “HIGH”

to a logic level “1” when ALL of its inputs are at logic level “1”. The output state of a

“Logic AND Gate” only returns “LOW” again when ANY of its inputs are at a logic

level “0”. In other words for a logic AND gate, any LOW input will give a LOW output.


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3.2.4 HCF4075B OR GATE IC

Fig 3.2.4(a) Fig 3.2.4(b)

The HCF4075B is a monolithic integrated circuit fabricated in Metal Oxide Semiconductor technology available in DIP and SOP packages. The HCF4075B


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TRIPLE 3 INPUT OR GATE provides the system designer with direct implementation of the positive logic OR functions and supplements the existing family of CMOS gates.

3.2.5 MCT2e OPTOCOUPLERS IC


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Opto-isolators or Opto-couplers, are made up of a light emitting device, and a light

sensitive device, all wrapped up in one package, but with no electrical connection

between the two, just a beam of light. The standard opt coupler circuits design uses a

LED shining on a phototransistor-usually it is an npn transistor and not pnp. The signal

is applied to the LED, which then shines on the transistor in the IC. The MCT2E series

of opto-coupler devices each consist of gallium arsenide infrared LED and a silicon

NPN phototransistor. They are packaged in a 6-pin DIP package and available in wide-

lead spacing. It is a combination of 1 LED and a transistor. Pin 6 of transistor is not

generally used and when light falls on the base-emitter junction then it switches and pin5

goes to zero.

3.2.6 ULN2003A IC

Fig 3.2.6(a) Fig 3.2.6(b)

Ideally suited for interfacing between low-level logic circuitry and multiple peripheral power loads, the Series ULN20xxA/L high-voltage, high-current Darlington arrays feature continuous load current ratings to 500 mA for each of the seven drivers. At an appropriate duty cycle depending on ambient temperature and number of drivers turned ON simultaneously, typical power loads totalling over 230 W (350 mA x 7,95 V) can be controlled. Typical loads include relays, solenoids, stepping motors, magnetic print hammers, multiplexed LED and incandescent displays, and heaters. All devices feature open-collector outputs with integral clamp diodes.The ULN2003A/L and ULN2023A/L have series input resistors selected for operation directly with 5 V TTL or CMOS. These devices will handle numerous interface needs — particularly those beyond the capabilities of standard logic buffers. The ULN2004A/L and ULN2024A/L have


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series input resistors for operation directly from 6 to 15 V CMOS or PMOS logic outputs. The ULN2003A/L and ULN2004A/L are the standard Darlington arrays. The outputs are capable of sinking 500 mA and will withstand at least 50 V in the OFF state. Outputs may be paralleled for higher load current capability. The ULN2023A/L and ULN2024A/L will withstand 95 V in the OFF state.

3.2.7 12V 250 OHM 4C/O RELAY

Fig 3.2.7(a) Fig 3.2.7(b)

Figure 3.2.7 shows a 12V 4 C/O relay. A relay is an electrically operated switch.

Many relays use an electromagnet to mechanically operate a switch, but other operating

principles are also used, such as solid-state relays. Relays are used where it is necessary

to control a circuit by a low-power signal (with complete electrical isolation between

control and controlled circuits), or where several circuits must be controlled by one

signal. The first relays were used in long distance telegraph circuits as amplifiers: they

repeated the signal coming in from one circuit and re-transmitted it on another circuit.

Relays were used extensively in telephone exchanges and early computers to perform

logical operations.

A type of relay that can handle the high power required to directly control an

electric motor or other loads is called a contactor. Solid-state relays control power

circuits with no moving parts, instead using a semiconductor device to perform

switching. Relays with calibrated operating characteristics and sometimes multiple

operating coils are used to protect electrical circuits from overload or faults; in modern

electric power systems these functions are performed by digital instruments still called

"protective relays".


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3.2.8 230V AC PRIMARY TO 12V, 500mA SECONDARY TRANSFORMER

Fig 3.2.8

Figure 3.2.8 shows a 230V AC primary to 12V, 500mA secondary transformer.

Three single phase transformers are used to step down the three phase supply separately.

Phases R, Y and B are stepped down by transformers X1,X2and X3 to deliver the

secondary output of 12V at 500 mA.

3.2.9 BC547 NPN TRANSISTOR

Fig 3.2.9

Figure 3.2.9 shows a BC547 NPN transistor. BC547 is an NPN bi-polar junction

transistor. A transistor, stands for transfer of resistance, is commonly used to amplify

current. A small current at its base controls a larger current at collector & emitter

terminals.

BC547 is mainly used for amplification and switching purposes. It has a maximum

current gain of 800. Its equivalent transistors are BC548 and BC549.

The transistor terminals require a fixed DC voltage to operate in the desired region of its

characteristic curves. This is known as the biasing. For amplification applications, the


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transistor is biased such that it is partly on for all input conditions. The input signal at

base is amplified and taken at the emitter.

3.3 COST ANALYSIS

The cost analysis of the components are shown in the table 3.3

COMPONENT QUANTITY COSTNE555 TIMER 3 30.00

IC 74LS04 1 10.00

IC 74LS11 3 2 20.00

IC HCF4075B 1 14.00

IC ULN2003A 1 12.00

IC MCT2E 3 36.00

DIODES 24 12.00

TRANSISTORS 3 9.00

RESISTORS 15 7.00

CAPACITORS 7 20.00

LEDS 10 10.00

PRESET 3 30.00

TRANSFORMERS 4 320.00

RELAYS 6 280.00

JUMPER WIRES 10 50.00

CONNECTING WIRES 100.00

Table 3.3


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4) DESIGN

4.1 DESIGN OFANTY SHORTING SYSTEM:

We have the relation for the pulse width of mono stable multi vibrator using IC 555 as,

tp = R* C* ln (3)

Let C= 100µF.

For tp= 1.5 s,

R = tp/(C* ln(3) ) = 1.5s / (100µF * ln(3) )

R = 1.5/(100*10-6*ln(3))

R = 13653.58 Ω = 13.65 KΩ (Using 15KΩ preset)

4.2 DESIGN OF LOGIC CIRCUIT

Design of this digital circuit is done using various steps of k map. By using k map

we found the digital logic high and low in order to operate our phase changer relay

combinations automatically


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5. WORKING

In case of 3 phase connections, if any phase cut off

the supply, we have to manually connect the missing phase to any available phase.

Usually we are using 3 phase supplies in buildings including offices, houses, industrial

buildings ...etc. where heavy duty is required. We cannot operate any devices if in case

all the three phases in 3 phase supply is missing.

Initially an external DC source of 18V is used for the supply and later supply is provided

from the load side for the section having three transformers with rectifier blocks and

optocoupler which is used to check whether the phase is available or not. Here


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optocoupler acts as switch which acts at different voltage levels; it contains an infrared

LED on input side and a photo detector on the outside side. The left source voltage and

the series resistors set up a current through the LED. Then the light from LED falls on

the photodiode which sets up a common reverse current in the output circuit. When the

input voltage is varied the amount of light fluctuates, this means that output voltage

varies in step with input voltage.

The external dc supply of 18V is dividing into 2 supplies using the Regulator IC. By

using a regulator IC, we are dividing this external supply to 5V and 15V. Where this

15V supply is used for the anti-shorting delay system. This system stops when the

missing phase arrives or it delays the arrival of the missing phase in order to avoid the

shorting of 2 phases due to mechanical time lag of the circuit and the relay. The other

5V supply is used for power up the digital circuit

Digital Circuit

For a 3 phase connection there are 8 combinations of RYB supplies with 0s and 1s,

ranging from 000 to 111.Except in case of 000 we can feed the missing phase using the

available phase. The conditions for missing any one of the phase are 110,011,101 and in

all of these conditions the phase changing relay system is energized. Similarly two

phases missing conditions are denoted by 100,010,001 and here both relays are

energized. In all the cases i.e. 001 to 111, 3 contact relays are energized.

Relays are electrically operated switches. It consist iron core surrounded by a control

coil. When current starts flowing through control coil the electromagnets starts

energizing and thus intensifies the magnetic field. Since relays are mechanical devices

which are operated on the basis of electromagnetic induction there will be some lagging

in ON/OFF conditions. So during phase sharing conditions the presence of missing

phase leads to the shorting of the two phases which can lead to serious errors and

damages. To take care of this condition an anti-shorting delay system is introduced

which brings the 3phase supply to phase changing portion, thereby missing phase

approaches only after the degeneration of phase changing relay and anti-shorting relay

will pass the missing phase. Anti-shorting relay system is controlled by means of a 555


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CONCLUSION

In three phase application if low voltage is available in any one

phase, and you want your equipment to work on normal voltage, this automatic phase

changer will solve your problem. This device is more reliable, is of less cost and

maintenance free. Automatic phase changer finds wide application in modem world.

During earlier days, if there is a power failure in any one of three phases, we have to

manually switch to the available phase. By implementing automatic phase changer it

automatically shifts to the phase where correct voltage is available. It can be used in

residences, small offices, buildings etc.


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Features:

For low- to high-power three-phase motors.

Reduced starting current

Six connection cables

Reduced starting torque

Advantages :

High switching speed

Low power consumption

Low cost

Small in size

Easy to install

Less switching noice

There is an option to take three phase connection.

Disadvantages:

Switching happen only if there is total power failure.

Three phase loads cannot attach to this system.

There is an external supply required.

Application of Automatic Phase Changer:

Small and medium scale industries

Residential Apartments


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Office

ATM

Factories operating with 1 phase machineries.

Hospitals/Banks/Institutions.

It automatically supplies voltage in case of power failure or low voltage in up to

2 of the 3 incoming phases.

Automatic Phase Changer automatically cuts supply during low voltage thus,

protects equipment from the harmful effects of unhealthily low voltage.

ANNEXURES

ANNEXURE 1( NE555 DATASHEET)


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ANNEXURE 2 (DM74LS04 DATASHEET)


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ANNEXURE 3 (74LS11 DATASHEET)


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ANNEXURE 4 (HCF4075B DATASHEET)


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ANNEXURE 4 (MCT2e DATASHEET)


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ANNEXURE 5 (ULN2003A DATASHEET)


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ANNEXURE 6(12V 3C/O RELAY DATASHEET)

COIL DATA (AT 25 C)

Nominal Coil

voltage (VDC)

Coil resistance

ohms(+/-10%)

Nominal Coil power

approx. (W)

Pick up voltage max.

(VDC)

Drop out voltage min.

(VDC)

NO12V 75

1.9W80% of nominal voltage

10% of nominal voltage

18V24V


• Non Plastic high temp. withstanding base• Insert moulded terminals• Screw / Solder type terminals• Suitable for motor starters & controllers

• Configuration : 3 NO (3 Form A)3 CO (3 Form C)

• Contact Rating : 30A at 240 VAC / 24 VDC(Resistive) (Higher AC voltage Contact rating Model also available)

• Contact Resistance : 100 mohm max (initial)

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Various coil voltages available.AC coils also available

pick up Voltage for AC coil relays 85% max. Of nominal coil voltage

GENERAL PERFORMANCES

• Operate time 30 msec max

Fast Switching version 10 msec max

• Release time 10 msec max

• Life Expectancy

Electrical 5x104 Operations at rated load

Mechanical 106 Operations

• Dielectric Strength

Between Open Contacts 1000 VAC

Between Coil & Contact 2000 VAC

Between Any terminal & earth 2000 VAC

• Insulation Resistance 1000 Mohm min @ 500 VDC, 25°C & RH 50

• Temp. Range -40°C to + 70°C

• Weight 200 gms (approx.)

• Mounting Chassis mounting


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BIBLIOGRAPHY

1. www.engineersgarage.com2. www.google.co.in 3. www.electricaleasy.com4. www.hobby2go.com5. www.wikipedia.org6. www.youtube.com7. www.eeweb.com 8. www.instructable.in 9. www.linkedin.in


http://www.linkedin.in/

http://www.instructable.in/

http://www.eeweb.com/

http://www.google.co.in/

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