ac generator new project 1.doc

7/21/2019 AC Generator New Project 1.doc

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Submitted To :

Mr. Anand Mishra

Submitted By :

Shubham Rai

XII-S1

ROLL.No. 44



Submitted To :

Mr. S.K. Tiwari

Submitted By :

SAURABH PRATAP

PARIHARXII-S2

ROLL.No. ...........



ACKNOWLEDEMENT

I express my deep sense of gratitude of

my guide Mr. Ma!an" Sin#h his

valuable guidance, inspiration and help

provided in every aspect of this project.

I am thankful to him for his constant

evaluation of this project and subsequent

in this regard.

Last but not the least; I extend my

sincere thanks to my Parents, school and

riends, !ho played an important role in

proper tunings of my project.

Mr. S.K. Tiwari

Ph!si$s T%a$h%r

N%ha &%rma

C'ass ( )*+h



CERTI,ICATE

This is certify that yoti

Rai of c!ass XII-S2 "Scie#ce of

Sa#t $tu!a#a#d Reside#tia!

$cademy% &ara#asi has

're'ared this (hysics 'ro)ect

*a!f +a,e Rectier.

I# accorda#ce +ith uide

!i#es fo!!o+ed by /.B.S.0.% Ne+

e!hi. She has +ored as 'er

the i#structio# a#d certies

that this 'rocess is u#i3ue a#d

#ot co'ied.

T%a$h%r-s Si#na+ur%

Mr. S.K. Tiwari



Ph!si$s T%a$h%r



/ONT0NT

1. I"#$%&'(#I%"

2. )*+I( *L -*/ $/(#II/$

(I$('I#

. -%$0I"1 % *L -*/

$/(#II/$

4. P%-/$ +'PPL2+P/(II(*#I%"+

5. *&*"#*1/+ *"&

&I+*&*"#*1/+

6. *L -*/ $/(#II/$ &I%&/

$/3'I$/4/"#+

7. )I)LI%1$*P2



INTRODUCTION

An electric generator is a device that converts mechanical

energy to electrical energy. A generator forces electric current to

flow through an external circuit. The source of mechanical energy

may be a reciprocating or turbine steam engine, water falling

through a turbine or waterwheel, an internal combustion engine,

a wind turbine, a hand crank , compressed air , or any other source

of mechanical energy. Generators provide nearly all of the power

for electric power grids

http://en.wikipedia.org/wiki/Mechanical_energy


http://en.wikipedia.org/wiki/Electrical_energy

http://en.wikipedia.org/wiki/Electrical_circuit

http://en.wikipedia.org/wiki/Turbine

http://en.wikipedia.org/wiki/Steam_engine

http://en.wikipedia.org/wiki/Hydropower

http://en.wikipedia.org/wiki/Internal_combustion_engine

http://en.wikipedia.org/wiki/Wind_turbine

http://en.wikipedia.org/wiki/Crank_(mechanism)

http://en.wikipedia.org/wiki/Compressed_air

http://en.wikipedia.org/wiki/Electric_power_grid

http://en.wikipedia.org/wiki/Electrical_energy

http://en.wikipedia.org/wiki/Electrical_circuit

http://en.wikipedia.org/wiki/Turbine

http://en.wikipedia.org/wiki/Steam_engine

http://en.wikipedia.org/wiki/Hydropower

http://en.wikipedia.org/wiki/Internal_combustion_engine

http://en.wikipedia.org/wiki/Wind_turbine

http://en.wikipedia.org/wiki/Crank_(mechanism)

http://en.wikipedia.org/wiki/Compressed_air

http://en.wikipedia.org/wiki/Electric_power_grid





THEORY

1. The strong magnetic field is produced by a current flow

through the field coil of the rotor.

2. The field coil in the rotor receives excitation through the use

of slip rings and brushes.

. Two brushes are spring!held in contact with the slip

rings to provide the continuous connection between the

field coil and the external excitation circuit.

". The armature is contained within the windings of the stator

and is connected to the output.

#. $ach time the rotor makes one complete revolution, one

complete cycle of A% is developed.

&. A generator has many turns of wire wound into the slots of the

rotor.

'. The magnitude of A% voltage generated by an A% generator is

dependent on the field strength and speed of the rotor.

(. )ost generators are operated at a constant speed* therefore,

the generated voltage depends on field excitation, or strength.



8OR9IN

All metals contain a movable substance called +electric charge+.

$ven uncharged wires are full of charge After all, the atoms of

the metal are made half of positive protons and half of negative

electrons. )etals are special because their electrons don-t stay

connected to the metal atoms, instead they fly around inside the

metal and form a type of electric +liuid+ inside the wires. All

wires are full of electric fluid. )odern scientists call this the

+electron sea+ or +electron gas.+ /t is not invisible, it actually

gives metals their silvery shine. The electron gas is like a silvery

fluid.

0hen a circle of wire surrounds a magnetic field, and the

magnetic field then changes, a circular +pressure+ called oltage

appears. This circular voltage trys to force the movable charges in

the wire to rotate around the circle. /n other words, moving

magnets create electric currents in closed circles of wire. A

moving magnet causes a pumping action. /f the circuit is not

complete, if there is a break, then the pumping force will cause

no charge flow. ut if the circuit is +complete+ or +closed+, then

the magnet-s pumping action can force the electrons of the coil to



begin flowing. This is a basic law of physics, and it is used by all

coil3magnet electric generators.

0hen the circuit is closed and the magnet is moving, charges in

the metal are forced to flow. The charges of the light bulb-s

filament are pushed along. 0hen the charges within the copper

wire pass into the thin light bulb filament, their speed greatly

increases. 0hen the charges leave the filament and move back

into the



;S0S

1. Aircraft auxiliary power generation, wind generators,

high speed gas turbine generators.

2. 4ybrid electric vehicle 54$6 drive systems,

automotive starter generators.

. An ac generator, or -alternator-, is used to produce ac

voltages for transmission via the grid system or, locally, as

portable generators.

". All of our household appliances runs on ac current.

$x7 8efrigerator, washing machines, oven, lights, fan etc.



0<<I/I0N/=

$xpression for /nstantaneous e.m.f. 9roduced7

:et position of the coil at any time t. /t make angle with

vertical. /f w is uniform angular speed of the coil.

Then ; wt

be the strength of magnetic field n be the number of turns inthe coil and A area of the coil then magnetic flux with the coil in

this position is given by7

f ; nA %os ; nA %os wt.

<ifferentiate w.r.t. time

; nA 5!=in wt6 w

; !nA w =in wt

e ; ! 5!nA w =in wt6

maximum value of e.m.f. say $>

e ; $> =in wt.

16 $fficiency of an A% generator is the ratio of the useful

power output to the total power input.

26 ecause any mechanical process experiences some losses,

no A% generators can be 1>> percent efficient.



6 $fficiency of an A% generator can be calculated using

$uation.

"6 $fficiency ;5?utput 3/nput 6 @ 1>>



I !ant to give my special thanks

to subject teacher >r. S.N. >ishra

for giving him precious time in

completion of my project !ork and

also to the Lab assistance >r. 9ashi

for guiding me in my practical !orks.

#hey helped me from the moment I

started my project to the end of it.

ac generator new project 1.doc

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