auto selection of any available phase
TRANSCRIPT
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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.