Auto Selection of Any Available Phase

8/11/2019 Auto Selection of Any Available Phase

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Introduction

The basic idea for the development of the project is to providesupply to the single phase load if any of the phases, out of

the 3 phases misses.

The three transformers are connected to the 3 phases supply

It automatically switch to next phase while one phase is misses.

For monitoring the phase shifting we are using NAND gatelogics.

The relay driver IC to change the load to the next phase through

the contacts those are fed from all the three phases.

At final condition it works on inverter .


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contents

IntroductionBlock diagram

Hardware requirements

Power supply

Gate

Opto isolatorRelay

Relay driver

Schematic diagram

Working of the projectAdvantages

Applications

Conclusion


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Block diagram


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Hardware requirements

TRANSFORMER (230 12 V AC)

VOLTAGE REGULATOR (LM 7805)

FILTER

RELAY

ULN 2003

OPTO ISOLATOR

AND GATE IC 4081INVERTER IC 4069

LED

1N4007

RESISTORCAPACITOR


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Hardware Components description

1. 230 V AC

50 Hz

12V step downtransformer

2. Using In4007 as Bridge rectifier

3. Capacitors Filter(470f) 4. 5v

Regulator

5. Relay


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6. ULN2003 7. OPTO-ISOLATOR

8. AND GATES IC 4081


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8. INVERTER IC 40699. LED

10. RESISTOR
http://en.wikipedia.org/wiki/File:Verschiedene_LEDs.jpg


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11. Capacitor

12. 3c/0 relay


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Power supply

Description of power supply


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Description of power supply

The circuit uses standard power supply comprising of a step-downtransformer from 230v to 12v and 4 diodes forming a Bridge Rectifier

that delivers pulsating dc which is then filtered by an electrolytic

capacitor of about 470microf to 100microF.

The filtered dc being un regulated IC LM7805 is used to get 5v

constant at its pin no 3 irrespective of input dc varying from 9v to 14v.The regulated 5volts dc is further filtered by a small electrolytic

capacitor of 10 micro f for any noise so generated by the circuit.

One LED is connected of this 5v point in series with a resistor of

330ohms to the ground i.e. negative voltage to indicate 5v power supply

availability.


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And Gate discription {Ic 4081}

The 4000 Series CMOS range, and contains four

independentCMOS AND gates each with two inputs.

Pin Description

Pin 7 is the negative supply

Pin 14 is the positive supply

Pins 1&2, 5&6, 8&9, 12&13 are gate inputs

Pins 3, 4, 10, 11 are gate outputs


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INVERTER IC 4069

The HCC/HCF4069UB consists of six COS/MOS

inverter circuits .This device is intended for all general purpose inverter

applications where the medium-power TTL-drive and

logic-level-conversion capabilities of circuits such as

HCC/HCF4049BHex Inverter/Buffers are not

required.

Medium-speed operation- tphl, tplh = 30ns (typ.) A 10v.

quiescent current specified to 20v for hcc device .

standardized symmetrical output characteristics .

5v, 10v, and 15v parametric ratings input current of

100na at 18v and 25c for hcc device .

100% tested for quiescent current .


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Opto-isolator

Opto coupler is a 6 pin IC. It is a combination of

1 LED and a transistor

Pin 6 of transistor is not generally used and whenlight falls on the Base-Emitter junction then it

switches and pin5 goes to zero.

RelayA relay is an electrically operated switch.

Current flowing through the coil of the relay

creates a magnetic field which attracts a lever and

changes the switch contacts.

The coil current can be on or off so relays have

two switch positions and have double throw

(changeover) switch contacts as shown in the

diagram.


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Relay driver uln2003

The ULN2003 is a monolithic high voltage

and high current Darlington transistor arrays.

It consists of seven NPN Darlington pairs that

features high-voltage outputs with common-

cathode clamp diode for switching inductive

loads.

The collector-current rating of a singleDarlington pair is 500mA.

The ULN functions as an inverter.

If the logic at input 1B is high then the output

at its corresponding pin 1C will be low.


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WORKING

Three phase supply are given to three independent transformers connected

in together with another transformers from receiving supply, an inverter .

The secondary of the transformers are used to develop DC by half waverectification and then deriving four number of opto isolators individually.

The DC supply from all the three phases and inverter supply are combined

and then fed to the regulator IC 7805 for the circuit operation power.

One quad inverter is used in combination with a quad AND the o/p of

which are fed to relay driver IC ULN2003.The combination of inverter and AND develops a logic of the i/p to the

relay driver IC logic high on the event of any source failure for the next

available supply.

The relays connected drive the load with interlocking logic from the

NO/NC contact such that the 1stphase load automatically changes over toany available phase in the event of the phase failure.

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Auto Selection of Any Available Phase