i'm a third year student. i need the entire details about "Automatic phase changer and control" to do my mini-project.

In three-phase applications, if lowvoltage is available in any one ortwo phases, and you want yourequipment to work on normal voltage,this circuit will solve your problem.However, a proper-rating fuse needsto be used in the input lines (R, Y andB) of each phase. The circuit providescorrect voltage in the same power supplylines through relays from the otherphase where correct voltage is available.Using it you can operate all yourequipment even when correct voltageis available on a single phase in the building.The circuit is built around a transformer,comparator, transistor and relay.Three identical sets of this circuit,one each for three phases, are used.Let us now consider the working ofthe circuit connecting red cable (call it‘R’ phase). The mains power supply phase Ris stepped down by transformer X1 todeliver 12V, 300 mA, which is rectifiedby diode D1 and filtered by capacitorC1 to produce the operatingvoltage for the operational amplifier(IC1). The voltage at inverting pin 2 ofoprational amplifier IC1 is taken fromthe voltage divider circuit of resistorR1 and preset resistor VR1. VR1 is usedto set the reference voltage accordingto the requirement. The reference voltageat non-inverting pin 3 is fixed to5.1V through zener diode ZD1.Till the supply voltage available inphase R is in the range of 200V-230V,the voltage at inverting pin 2 of IC1remains high, i.e., more than referencevoltage of 5.1V, and its output pin 6also remains high. As a result, transistorT1 does not conduct, relay RL1 remainsde-energised and phase ‘R’ suppliespower to load L1 via normallyclosed(N/C) contact of relay RL1.As soon as phase-R voltage goesbelow 200V, the voltage at invertingpin 2 of IC1 goes below reference voltageof 5.1V, and its output goes low.As a result, transistor T1 conducts andrelay RL1 energises and load L1 isdisconnected from phase ‘R’ andconnected to phase ‘Y’ through relayRL2.Similarly, the auto phase-change ofthe remaining two phases, viz, phase‘Y’ and phase ‘B,’ can be explained.Switch S1 is mains power ‘on’/’off’switch.Use relay contacts of proper ratingand fuses should be able to take-onthe load when transferred from otherphases. While wiring, assembly and installationof the circuit, make sure thatyou:

Download full report
http://pecworld.zxqAssets/SOURCE/PDF_fun...July07.pdf

to get information about the topic "automatic phase changer" full report ppt and related topic refer the page link bellow

http://studentbank.in/report-automatic-p...ull-report

http://studentbank.in/report-automatic-p...nd-control