wild life documentary

7/21/2019 wild life documentary

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Project overview• Three single phase transformers are wired in star input

and star output having input $$% volt and output at &$ volt'

• The contact relays which are used energi(ed from the

output of comparators in the event of fault conditions )y

tracking the input voltage conditions for each phase at the

input of the comparators'• Two 555 timers are used* one in monosta)le and the

other in asta)le mode to drive a power relay that handles

the load'

• " Set of switches are used to introduce LL fault* L+ fault *,L short to get the comparator output to drive )oth the

relays to disconnect the load'

• Short duration fault returns the load immediately while

long duration shall result in permanent trip'



Block diagram



Transmission line #aults

• #ault types include-• Single line to ground.L+/

• Line to line.LL/

• 0ou)le line to ground.LL+/

• Three phase )alanced



Comparator

•op amps comparators look very similar

• But a comparator gives a logic output

indicating the relative potentials on its two

inputs

• "n op amp amplifies the differential

voltage )etween its two inputs 1 and is

designed always to )e used in closed2loop

applications



555 Timer • The 555 Timer C is an integrated circuit .chip/

implementing a variety of timer and multivi)rator

applications'

• The original name was the S6555 .metal can/786555

.plastic 0P/ and the part was descri)ed as 9The C Time

:achine9'

• 0epending on the manufacturer* the standard 555 package

includes over $% transistors* $ diodes and &5 resistors on a

silicon chip installed in an ;2pin mini dual2in2line package

.0P2;/



P8 0"+R": <# 555

The 555 timer C is a simple ; pin 0Lpackage C'

It can:

)e used as a monosta)le

)e used as an asta)le

source or sink &%%m"

use supply voltages of 5v to &5v

disrupt the power supply 2 use a

decoupling capacitor=



Relay• " relay is an electrically operated switch'

• Current flowing through the coil of the relaycreates a magnetic field which attracts a lever

and changes the switch contacts'

•The coil current can )e on or off so relayshave two switch positions and have double

throw .changeover / switch contacts as

shown in the diagram'



Contd''• Relays allow one circuit to switch a second

circuit which can )e completely separatefrom the first'

• #or e>ample a low voltage )attery circuit

can use a relay to switch a $,%4 "C mainscircuit'

• There is no electrical connection inside the

relay )etween the two circuits* the link ismagnetic and mechanical'

• To drive relay through :C ?L8$%%, relay

driver C is used



Contd''



!orking of project•

n this project two 555 timers are used & inmonosta)le mode and other in asta)le

mode'

•

!hen any push )utton is pressed for ashort time the load is disconnected only

for that period indicating a temporary fault'

• f the push )utton is pressed for longer

time then the asta)le timer s activated and

it causes a permanent fault and

disconnects the load permanently'

wild life documentary

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