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AUTO SELECTION OF ANY AVAILABLE PHASE, IN 3 PHASE SUPPLY SYSTEM. Submitted By. I ntroduction. 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.
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AUTO SELECTION OF ANY AVAILABLE PHASE, IN 3 PHASE SUPPLY SYSTEM Submitted By
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 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 gate • logics. • 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 .
contents Introduction Block diagram Hardware requirements Power supply Gate Opto isolator Relay Relay driver Schematic diagram Working of the project Advantages Applications Conclusion
Hardware requirements • TRANSFORMER (230 – 12 V AC) • VOLTAGE REGULATOR (LM 7805) • FILTER • RELAY • ULN 2003 • OPTO ISOLATOR • AND GATE IC 4081 • INVERTER IC 4069 • LED • 1N4007 • RESISTOR • CAPACITOR
Hardware Components description 1. 230 V AC 50 Hz 12V step down transformer 2. Using In4007 as Bridge rectifier 4. 5v Regulator 3. Capacitors Filter(470µf) 5. Relay
6. ULN2003 7.OPTO-ISOLATOR 8.AND GATES IC 4081
8. INVERTER IC 4069 9. LED 10. RESISTOR
11. Capacitor 12. 3c/0 relay
Power supply Description of power supply
Description of power supply • The circuit uses standard power supply comprising of a step-down transformer 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.
And Gate discription {Ic 4081} • The 4000 Series CMOS range, and contains four independent • CMOS 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
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 25°c for hcc device . • 100% tested for quiescent current .
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 when • light falls on the Base-Emitter junction then it • switches and pin5 goes to zero. Relay • A 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.
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 single • Darlington 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.
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 wave • rectification 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 1st phase load automatically changes over to • any available phase in the event of the phase failure.