Electromagnetic brake solenoid coil 2014

FABRICATION OF ELECTROMAGNETIC BRAKING SYSTEM

Submitted in the partial fulfillment of the requirement for the award of

“DIPLOMA IN AUTOMOBILE ENGINEERING ”

SUBMITTED BY:

1. G.K. MANIGANDAN 4. J. DHANAJEYAN 2. B. KARTHIKEYAN 5. D. DURAIVEL 3. P. BALASUBRAMANI 6. L. PRABHU

Under guidance of

Mr. V.K. RAJENDRAN,M.E.

MARCH 2013.

DEPARTMENT OF AUTOMOBILE ENGINEERING

A M K TECHNOLOGICAL POLYTECHNIC COLLEGECHEM BARAMBAKKAM, CHENNAI – 602 103

A M K TECHNOLOGICAL POLYTECHNIC COLLEGECHEM BARAMBAKKAM, CHENNAI – 602 103

BONAFIDE CERTIFICATE

This is to certify that this Project work on

“FABRICATION OF ELECTROMAGNETIC BRAKING SYSTEM”

submitted by …………………… ……………. Reg. No. ……………

in partial fulfillment for the award of

DIPLOMA IN AUTOMOBIL ENGINEERING

This is the bonafide record of work carried out by him under

our supervision during the year 2013

Submitted for the Viva-voce exam held on ……………..

HEAD OF THE DEPARTMENT PROJECT GUIDE

INTERNAL EXAMINER EXTERNAL EXAMINER

ACKNOWLEDGEMENT

ACKNOWLEDGEMENT

At the outset, we would like to emphasize our sincere thanks to the

Principal Mr. A.VIJAY KISHORE M.TECH MISTE.,., encouragement

and valuable advice.

we thank our Esquired Head of Department Mr R. RAJKUMAR,

A.M.I.E, M.E., for presenting his felicitations on us.

We are grateful on our Entourages Mr.S,MURALI M.E., for

guiding in various aspects of the project making it a grand success.

We also owe our sincere thanks to all staff members of the

Mechanical Engineering (MTMR) Department.

Ultimately, we extend our thanks to all who had rendered their co-

operation for the success of the project.

CONTENTS

CONTENTS

Chapter No. TITLE

1. INTRODUCTION

2. SYNOPSIS

3. CONSTRUCTION

4. WORKING PRINCIPLE

5. BRAKE CIRCUIT DIAGRAM

6. MECHANICAL SPARE PARTS DETAILS

7. ELECTRICAL PARTS DETAILS

8. ELECTRICAL CIRCUIT DETAILS

9. FINISHING AND PAINTING

10. COST ESTIMATION

11. CONCLUSION

12. BIBILOGRAPHY

INTRODUCTION

INTRODUCTION

This is a self – assessment test on the part of the students to assess his

competency in creativity.

During the course of study, the student is put on a sound theoretical

foundation of various mechanical engineering subjects and of course, to a

satisfactory extent. Opportunities are made available to him to work on

different kinds of machines, so that he is exposed to various kinds of

manufacturing process.

As a students learn more and more his hold on production technology

becomes stronger. He attains a stage of perfection, when he himself is able

to design and fabricate a device.

This is the project work. That is the testimony for the strenuous

training, which the student had in the institute. This assures that he is no

more a student, he is an engineer.

This report discuses the necessity of the project and various aspects of

planning , design, selection of materials, fabrication, erection, estimation and

testing.

SYNOPSIS

SYNOPSIS

Electric brakes a type of the braking system not very popular

can be used commercially in passenger cars as they have several advantages.

Electromagnetic brakes are used in other fields such as bottling plants. They

are used for bringing the assembly to a quick stop each time for filling up the

bottles. In this project we propose to deal with a new type of electromagnetic

brake using solenoid switch. Most magnetic breaking relay on the attractive

force generated within a gap magnetic circuit which generates forces on the

supported shaft because this force is quadratic magnetic flux intensity in the

circuit: it is only possible to pull the shaft to accomplish bi or

multidirectional control of the shaft.

Several electromagnets are arranged around the shaft and are operated

differentially to improve the linearity and dynamic performance of these

differentially arranged magnets. It is commons to free bias the air gaps with

constant flux density. This biasing can be accomplished in a number of ways

but usually it is done by applying a biasing current to the oils, which

energize the magnetic circuits. The primary advantages of this scheme a

reduction in electrical power consumption. Magnetic bearings employ the

repulsive forces of opposed magnetic fields generated by electromagnets in

this slider and the base. They achieve straight line accuracy to 0.00004-

inches / foot through a control loop that employs capacity, proximately

sensos in position feed back for controlling the amplifiers that generate the

magnetic fields. Magnetic breaking can support loads in excess of 1000

pounds, magnetic Breaking have no moving parts to wear and can be used in

vacuum condition soothers is no friction in contact places.

The electro magnetic brake operates in 12VDC power supply. When the

supply given to the electromagnetic coil which pulls the brake lever to apply

the brake to the rotating wheel.

Block Diagram;

DC Power Supply

ELECTRO MAGNETIC BRAKE

Switch to apply brake

Brake lever

Wheel

CONTRUCTION

CONTRUCTION

This unit consists of

1) M.S. FABRICATED STAND UNIT

2) DC POWER SUPPLY WITH SWITCH

3) ELECTROMAGNETIC COIL UNIT

4) BRAKING UNIT

1)M.S. FABRICATED STAND UNIT ;

The rear wheel for two wheeler bike is dismantled and mounted in the M.S.

fabricated stand. This stand is made in 25x25x 3 mm size L angle. In this

electromagnetic coil unit is fitted . this solenoid coil has one central iron rod

which is connected to brake drum lever against spring force control.

2)DC POWER SUPPLY WITH SWITCH

POWER SUPPLY 5V DC AND 12V DC;

A 12 –0 v step down transformer is used to stepdown 230V AC to

12V AC .This 12V AC supply is converted to 12V DC using four rectifier

diodes. The voltage from the rectifier section is regulated to 12V DC using

7812 IC . From 12V DC the 7805 IC is used for regulating 5V DC for the

power supply of microcontroller.

the power supply circuit is shown in fig.

3. POWER SUPPLY UNIT ;

INTRODUCTION:

All the electronic components starting from diode to Intel IC’s only

work with a DC supply ranging from +5V to +12V. We are utilizing for the

same, the cheapest and commonly available energy source of 230V-50Hz

and stepping down, rectifying, filtering and regulating the voltage.

STEP DOWN TRANSFORMER:

When AC is applied to the primary winding of the power transformer,

it can either be stepped down or stepped up depending on the value of DC

needed. In our circuit the transformer of 230V/15-0-15V is used to perform

the step down operation where a 230V AC appears as 15V AC across the

secondary winding. Apart from stepping down voltages, it gives isolation

between the power source and power supply circuitries.

RECTIFIER UNIT:

In the power supply unit, rectification is normally achieved using a

solid state diode. Diode has the property that will let the electron flow easily

in one direction at proper biasing condition. As AC is applied to the diode,

electrons only flow when the anode and cathode is negative. Reversing the

polarity of voltage will not permit electron flow. A commonly used circuit

for supplying large amounts of DCpower is the bridge rectifier. A bridge

rectifier of four diodes (4 x IN4007) are used to achieve full wave

rectification. Two diodes will conduct during the negative cycle and the

other two will conduct during the positive half cycle, and only one diode

conducts. At the same time one of the other two diodes conducts for the

negative voltage that is applied from the bottom winding due to the forward

bias for that diode. In this circuit due to positive half cycle D1 & D2 will

conduct to give 0.8V pulsating DC. The DC output has a ripple frequency

of 100Hz. Since each alteration produces a resulting output pulse, frequency

= 2 x 50 Hz. The output obtained is not a pure DC and therefore filtration

has to be done.

The DC voltage appearing across the output terminals of the bridge

rectifier will be somewhat less than 90% of the applied rms value. Normally

one alteration of the input voltage will reverse the polarities. Opposite ends

of the transformer will therefore always be 180 degree out of phase with

each other. For a positive cycle, two diodes are connected to the positive

voltage at the top winding.

3)ELECTROMAGNETIC COIL UNIT;

This unit having one solenoid coil operated in 12VDC supply voltage.

There is a metal rod centrally mounted in the coil under spring force. When

the supply is given to the coil unit ,the solenoid core rod moves inward in

to the coil and the metal rod pull the brake lever pedal downward

direction. This coil is connected to the power supply through a button.

4)BRAKING UNIT

Drum brakes consist of a backing plate, brake shoes, brake drum, wheel

cylinder, return springs and an automatic or self-adjusting system. When you

apply the brakes, brake fluid is forced, under pressure, into the wheel

cylinder which, in turn, pushes the brake shoes into contact with the

machined surface on the inside of the drum. When the pressure is released,

return springs pull the shoes back to their rest position. As the brake linings

wear, the shoes must travel a greater distance to reach the drum. When the

distance reaches a certain point, a self-adjusting mechanism automatically

reacts by adjusting the rest position of the shoes so that they are closer to the

drum.

WORKING OPERATION

WORKING OPERATION

. In this project we propose to deal with a new type of electromagnetic

brake using solenoid switch.

This unit having one solenoid coil operated in 12VDC supply

voltage. There is a metal rod centrally mounted in the coil under spring

force. When the supply is given to the coil unit ,the solenoid core rod moves

inward in to the coil and the metal rod pull the brake lever pedal

downward direction. This coil is connected to the power supply through a

button.

The electro magnetic brake operates in 12VDC power supply. When the

supply given to the electromagnetic coil which pulls the brake lever to apply

the brake to the rotating wheel.

Block Diagram;

DC Power Supply

ELECTRO MAGNETIC BRAKE

Switch to apply brake

Brake lever

Wheel

ADVANTAGE

ADVANTAGE ;

1. Easy to install and low cost.

2. Repair and maintenance is simple.

3. It is used as a safety device duo to over load

DISADVANTAGES

DISADVANTAGES

1. Braking speed is constant

2. This braking is not a smooth one.

3. High battery power is required.

4. May be chance of electro-magnetic coil failure.

APPLICATIONS

APPLICATIONS

1. Used in machinetool spindle gear box system to change the speed.

2. Used in crane control system

3. Used in winch controlling

4. Used in lift controlling

5. Used in automobile purpose

BASIC REQUIREMENTS

OF A BRAKE

BASIC REQUIREMENTS OF A BRAKE:

The brake must be strong enough to stop the vehicle with a minimum

distance. The distance should be the shortest during Emergency braking. The

distance moved by the vehicle after the application of the brake is known as

braking.

The brakes must have good ant fade characteristic. In other words the

brakes should not loose their effectiveness on prolonged application. This is

only possible by proper and effective cooling of brakes.

PURPOSE OF BRAKES

PURPOSE OF BRAKES:

1. To control the speed of the vehicle as well as to stop it when and

where desired quickly and efficiently without sticking.

2. To keep the vehicle is any possible position after it had been actually

brought to a complete rest when the driver is not present.

3. These purposes are accomplished by providing two independent

braking systems in a motor vehicle service brake and a parking (or)

emergency on hand brake.

PRINCIPLES OF

BRAKING

PRINCIPLES OF BRAKING:

The principle of braking is the reverse of that applied during

accelerating a vehicle. in accelerating, the heat energy of the fuel is

converted into the power of kinetic energy is converted into heat by means

of friction produced between low mating surface of the brake drum. similar

to the effective effort produced at the peripheries of the driving of the motor

vehicle, the braking torque introduced at the brakes drums due to application

of brake produces a retarding effort (or) a negative attractive effort is limited

bay the adhesion available between the brake lining and the brake drum

similar to the limit providing by the adhesion available between the wheels

and the grant. the force of friction (or) force exerted on the shoes by the

retarding mechanism and the co-efficient of friction for the two materials.

BRAKE TESTING:

BRAKE TESTING:

When the vehicle is moving, it can be stopped by applying the brakes.

It is to be noted here that brake pedals cannot be passed instantaneously and

the vehicle cannot be stopped instantaneously. First the drive thinks, then lift

the leg., presses the brake pedal and the vehicle stops after moving some

distance. So it is necessary to note how much time is required to stop the

vehicle and how long it will travel after applying the brake. These two

factors are directly dependent on the speed o the vehicle.

STOP TEST:

For testing the brakes, this test is usually adopted by mechanical or

driver after overhauling the brakes the moves the vehicle at a speed and

suddenly applies the brakes. Then he checks how much time it has taken to

stop and how long it has moved after spring the brakes. Also, he sees the

impressions of the four tyres on the road, whether equal or not, and whether

the vehicle is pulling a side or not.

STOP WATCH TEST:

To perform this test, the vehicle is moved at about 70km/hr. then the

brakes are applied. The time and distance are noted.

Let T = time taken to stop the vehicle after applying the brakes.

D = distance moved by the vehicle after applying the brakes.

Then, brake efficiency is given by

N = (D-T2)*6 ¼

Brake testers are also used for testing the brakes. They work on the principle

of decelerometer. Taply brake meter is a type of brake tester. This brake

meter is placed on the vehicle floor for testing the brakes. It consists of a

round ring with numbers. There is a pendulum inside the dial which remain

dipped in oil. As soon as the brake are applied, the vehicle speed decreases

which causes the pendulum ring to move. The number on the ring gives

reading which can be obtained by an inspection plate.

BRAKE SERVICE

BRAKE SERVICE:

Following is the procedure to service the brakes

1. Check the fluid level in the master cylinder

2. Check brake pedal adjustments.

3. Check brake pedal travel: If the pedal travels more than halfway to the

floor, the brakes may require adjusting to compensate for lining wear

or they may be require relining.

4. If the brakes pull to one side after adjustment, check tyre pressure. All

tyros must be inflated to recommended pressures to ensure even

braking. Check brake linings for foreign materials and clean as

required. If the side pull persists, check from wheel alignment and

balance.

5. Check the bake system for leaks by applying a steady pressure on the

break pedal. If the pedal falls away the break system has leak

somewhere. Find the leak points and remove them.

6. A spongy brake pedal indicates the presence of air in the hydraulic

system. This condition must be corrected by bleeding the brakes.

7. If the brakes become locked so that the vehicle cannot be moved the

brakes must be released by opening, the bleeder screw on any one of

the wheel cylinders.

DESCRIPTION OF BRAKE SYSTEM

CHAPTER – 1

DESCRIPTION OF BRAKE SYSTEM

1.1 INTRODUCTION

1.1 INTRODUCTION

Brakes are one of the most important control components of the

vehicle. They are required to stop the vehicle within the smallest possible

distance and this is done by converting the kinetic energy of the wheels into

the heat energy which is dissipated into the atmosphere.

Types of brakes based on method of actuation:

1. Mechanical brakes

2. Hydraulic brakes

3. Electric and electronic brakes

4. Vacuum brakes

5. Air brakes

Types of brakes based on application

1. Drum brakes

2. Disc brakes

3. Parking Brakes

1.2 DRUM BRAKES

The modern automobile drum brake was invented in 1902 by Louis

Renault, though a less - sophisticated drum brake had been used by

Maybach a year earlier. In the first drum brakes, the shoes were

mechanically operated with levers and rods or cables. From the mid-1930s

the shoes were operated with oil pressure in a small wheel cylinder and

pistons, though some vehicles continued with purely-mechanical systems for

decades. Some designs have two wheel cylinders.

The shoes in drum brakes are subject to wear and the brakes needed to be

adjusted regularly until the introduction of self adjusting drum brakes in the

1950s. In the 1960s and 1970s brake drums on the front wheel of cars were

gradually replaced with disc brakes and now practically all cars use disc

brakes on the front wheels, with many offering disc brakes on all wheels.

However, drum brakes are still often used for handbrakes as it has proved

very difficult to design a disc brake suitable for holding a car when it is not

in use. Moreover, it is very easy to fit a drum handbrake inside a disc brake

so that one unit serves for both footbrake and handbrake.

Early type brake shoes contained asbestos. When working on brake

systems of older cars, care must be taken not to inhale any dust present in

the brake assembly. The United States Federal Government began to

regulate asbestos production, and brake manufactures had to switch to non-

asbestos linings. Owners initially complained of poor braking with the

replacements; however, technology eventually advanced to compensate. A

majority of daily-driven older vehicles have been fitted with asbestos-free

linings. Many other countries also limit the use of asbestos in brakes.

Drum brakes consist of a backing plate, brake shoes, brake drum,

wheel cylinder, return springs and an automatic or self-adjusting system.

When you apply the brakes, brake fluid is forced, under pressure, into the

wheel cylinder which, in turn, pushes the brake shoes into contact with the

machined surface on the inside of the drum. When the pressure is released,

return springs pull the shoes back to their rest position. As the brake linings

wear, the shoes must travel a greater distance to reach the drum. When the

distance reaches a certain point, a self-adjusting mechanism automatically

reacts by adjusting the rest position of the shoes so that they are closer to the

drum.

1.2.1 BRAKE SHOES

Like the disc pads, brake shoes consist of a steel shoe with the friction

material or lining riveted or bonded to it. Also like disc pads, the linings

eventually wear out and must be replaced. If the linings are allowed to wear

through to the bare metal shoe, they will cause severe damage to the brake

drum.

1.2.2 BACKING PLATE

The backing plate is what holds everything together. It attaches to the

axle and forms a solid surface for the wheel cylinder, brake shoes and

assorted hardware. It rarely causes any problems.

1.2.3 BRAKE DRUM

Brake drums are made of iron and have a machined surface on the

inside where the shoes make contact. Just as with disc rotors, brake drums

will show signs of wear as the brake linings seat themselves against the

machined surface of the drum. When new shoes are installed, the brake

drum should be machined smooth. Brake drums have a maximum diameter

specification that is stamped on the outside of the drum. When a drum is

machined, it must never exceed that measurement. If the surface cannot be

machined within that limit, the drum must be replaced.

1.2.4 WHEEL CYLINDER

The wheel cylinder consists of a cylinder that has two pistons, one on

each side. Each piston has a rubber seal and a shaft that connects the piston

with a brake shoe. When brake pressure is applied, the pistons are forced out

pushing the shoes into contact with the drum. Wheel cylinders must be

rebuilt or replaced if they show signs of leaking.

The major components of the drum brake assembly is shown in the

following figure the detailed exploded view of drum brake components.

1.2.5 RETURN SPRINGS

Return springs pull the brake shoes back to their rest position after the

pressure is released from the wheel cylinder. If the spring are weak and do

not return the shoes all the way, it will cause premature lining wear because

the linings will remain in contact with the drum. A good technician will

examine the springs during a brake job and recommend their replacement if

they show signs of fatigue. On certain vehicles, the technician may

recommend replacing them even if they look good as inexpensive insurance.

1.2.6 SELF ADJUSTING SYSTEM

The parts of a self adjusting system should be clean and move freely

to insure that the brakes maintain their adjustment over the life of the

linings. If the self adjusters stop working, you will notice that you will have

to step down further and further on the brake pedal before you feel the

brakes begin to engage. Disc brakes are self adjusting by nature and do not

require any type of mechanism. When a technician performs a brake job,

aside from checking the return springs, he will also clean and lubricates the

self adjusting parts where necessary.

1.3 PARKING BREAKS

The parking brake (a.k.a. emergency brake) system controls the rear

brakes through a series of steel cables that are connected to either a hand

lever or a foot pedal. The idea is that the system is fully mechanical and

completely by passes the hydraulic system so that the vehicle can be brought

to a stop even if there is a total brake failure.

In drum brakes, the cable pulls on a lever mounted in the rear brake

and is directly connected to the brake shoes. This has the effect of by passing

the wheel cylinder and controlling the brakes directly.

1. Support plate

2. Park brake shoes

3. Equalizer

4. Springs

5. Hold down clips

6. Adjuster

Disc brakes on the rear wheels add additional complication for parking

brake systems. There are two main designs for adding a mechanical parking

brake to rear disc brakes. The first type uses the existing rear wheel caliper

and adds a lever attached to a mechanical corkscrew device inside the

caliper piston. When the parking brake cable pulls on the lever, this

corkscrew device pushes the piston against the pads, thereby bypassing the

hydraulic system, to stop the vehicle. This type of system is primarily used

with single piston floating calipers, if the caliper is of the four piston fixed

type, then that type of system can’t be used. The other system uses a

complete mechanical drum brake unit mounted inside the rear rotor. The

brake shoes on this system are connected to a lever that is pulled by the

parking brake cable to activate the brakes. The brake “drum” is actually the

inside part of the rear brake rotor.

On cars with automatic transmissions, the parking brake is rarely used.

This can cause a couple of problems. The biggest problem is that the brake

cables tend to get corroded and eventually size up causing the parking brake

to become inoperative. By using the parking brake from time to time, the

cables stay clean and functional. Another problem comes from the fact that

the self adjusting mechanism on certain brake systems uses the parking

brake actuation to adjust the brakes. If the parking brake is never used, then

the brakes never get adjusted.

1.4 DISC BRAKES

1.4.1 INTRODUCTION

Disc brakes consist of a metal disc attached to the wheel hub that

rotates with the wheel. Calipers are attached to the frame or fork along with

pads that squeeze together on the disc. Such brakes have been successfully

used on motorcycles for decades, and been the principal choice there. The

disc brake is a lot like the brakes on bicycle. Bicycle brakes have a caliper,

which squeezes the brake pads against the wheel. In a disc brake, the brake

pads squeeze the rotor instead of the wheel, and the force is transmitted

hydraulically instead of through a cable. Friction between the pads and the

disc slows the disc down.

1.4.2 CONSTRUCTION

THEORY OF CONVENTIONAL HYDRAULIC DISC BRAKE

A Disc brake uses a flat, round disc or rotor, attached to the

wheel hub instead of a drum. Brake pads are positioned on the opposite sides

of the rotor and are mounted in the brake caliper. The caliper contains the

hydraulic piston used to apply the shoes and to transmit the braking forces

from the shoes to the suspension members.

All disc brakes are non energized, non servo brakes; lining pressure is

directly proportional to brake pedal pressure.

Centrifugal force will throw the contaminants off the rotor. A disc brake will

have much cooler operation than drum brakes because of increased area that

is exposed to the air flowing past it.

All modern automotive brake system uses a hydraulic system to

transmit the application forces from the brake pedal to the brake shoes.

The brake’s hydraulic system begins at the master cylinder. The

master cylinder is basically a piston type hydraulic pump operated by the

brake pedal. As brake pedal is pushed, brake fluid is pumped to the caliper

or wheel cylinder piston. This fluid pushes on the pistons, which push the

brake shoes against the rotor.

1.4.3 ADVANTAGES OF DISC BRAKES OVER DRUM BRAKES

In case of disc brakes the frictions surface is directly exposed to the

cooling air, so the heat dissipation is much easier in disc brake than

drum brakes.

The frictional surface in case of disc brakes are flat when compared to

curved surface of drum brakes, this mean in disc brakes there is

uniform wear.

Frictional pad material is not subjected to any bending, thereby

increasing the range of materials from which to choose the suitable

one.

The design of disc brakes is such that there is no loss efficiency due to

expansion, as the system becomes hot, expansion of drum of

internally expanded shoe types if brake tends to move the friction

surface apart, causing a loss of effective pedal travel, on the friction

surfaces slightly without tending to increase the clearance.

Disc brake weigh less than their conventional drum type counterpart a

saving approximately 20% being possible.

Disc brake has a better anti fade characteristics than drum brakes.

1.4. DISADVANTAGES

Any leakages of hydraulic fluid leads to brake failure

Air bubbles if any got trapped in the hydraulic circuit will result is

brake failure.

Sufficient level of brake fluid should always be maintained all the

time

Hydraulic disc brakes usually require relatively specialized tools to

bleed the brake systems.

Repairs on the trail are difficult to perform, whereas mechanical disc

brakes rarely fail completely.

Considering the above mentioned advantages and superior nature of disc

brakes we decided to choose modifications in disc brakes to make it much

simpler and more effective and cheaper design.

1.5 HYDRAULIC VS MECHANICAL

Two main disc brake systems exist: hydraulic and mechanical (cable-

actuated). Mechanical disc brakes (which are almost always less expensive

than hydraulic) have less modulation than hydraulic disc brake systems, and

since the cable is usually open to the outside, mechanical disc brake tend to

pick up small bits of dirt and grit in the cable lines when ridden in harsh

terrain. Hydraulic disc rakes use fluid from a reservoir, pushed through a

hose, to actuate the pistons in the disc caliper that then actuate the pads.

Hydraulic disc brake systems generally keep contaminants out better.

However, since hydraulic disc brakes usually require relatively specialized

tools to bleed the brake systems, repairs on the trail are difficult to perform,

whereas mechanical disc brakes rarely fail completely. Hydraulic disc

brakes occasionally require bleeding of the brake lines to remove air

bubbles. There are two types of brake fluid used in disc brakes today:

mineral oil and DOT fluid. Mineral oil is generally inert and while DOT has

a higher boiling point, it is known to be corrosive to frame paint. The two

are generally not interchangeable, as the different fluids may cause seals to

swell or be corroded. Also, the hydraulic fluid may boil on steep, continuous

down hills. This is due to heat building up in the disc and pads and can cause

the brake to lose its ability to transmit force through incompressible fluids,

since some of it has become a gas, which is compressible. To avoid this

problem, 203 mm (8 inch) diameter disc rotors have become common on

downhill bikes. Larges rotors dissipate heat more quickly and have a larger

amount of mass to absorb heat. For these reasons, one must weigh the

advantages and disadvantages of using a hydraulic system versus a

mechanical system.

POWER SUPPLY 5V DC AND 12V DC;

A 12 –0 v step down transformer is used to step-down 230V AC to

12V AC .This 12V AC supply is converted to 12V DC using four rectifier

diodes. The voltage from the rectifier section is regulated to 12V DC using

7812 IC .This voltage is used for supply for the DC motor. From 12V DC

the 7805 IC is used for regulating 5V DC for the power supply of

microcontroller. The power supply circuit is shown in fig.

POWER SUPPLY UNIT

INTRODUCTION:

All the electronic components starting from diode to Intel IC’s only

work with a DC supply ranging from +5V to +12V. We are utilizing for the

same, the cheapest and commonly available energy source of 230V-50Hz

and stepping down, rectifying, filtering and regulating the voltage.

STEP DOWN TRANSFORMER:

When AC is applied to the primary winding of the power transformer,

it can either be stepped down or stepped up depending on the value of DC

needed. In our circuit the transformer of 230V/15-0-15V is used to perform

the step down operation where a 230V AC appears as 15V AC across the

secondary winding. Apart from stepping down voltages, it gives isolation

between the power source and power supply circuitries.

RECTIFIER UNIT:

In the power supply unit, rectification is normally achieved using a

solid state diode. Diode has the property that will let the electron flow easily

in one direction at proper biasing condition. As AC is applied to the diode,

electrons only flow when the anode and cathode is negative. Reversing the

polarity of voltage will not permit electron flow. A commonly used circuit

for supplying large amounts of DCpower is the bridge rectifier. A bridge

rectifier of four diodes (4 x IN4007) are used to achieve full wave

rectification. Two diodes will conduct during the negative cycle and the

other two will conduct during the positive half cycle, and only one diode

conducts. At the same time one of the other two diodes conducts for the

negative voltage that is applied from the bottom winding due to the forward

bias for that diode. In this circuit due to positive half cycle D1 & D2 will

conduct to give 0.8V pulsating DC. The DC output has a ripple frequency

of 100Hz. Since each alteration produces a resulting output pulse, frequency

= 2 x 50 Hz. The output obtained is not a pure DC and therefore filtration

has to be done.

The DC voltage appearing across the output terminals of the bridge

rectifier will be somewhat less than 90% of the applied rms value. Normally

one alteration of the input voltage will reverse the polarities. Opposite ends

of the transformer will therefore always be 180 degree out of phase with

each other. For a positive cycle, two diodes are connected to the positive

voltage at the top winding.

FILTERING CIRCUIT:

Filter circuits which is usually capacitor acting as a surge arrester

always follow the rectifier unit. This capacitor is also called as a decoupling

capacitor or a bypassing capacitor, is used not only to ‘short’ the ripple with

frequency of 120Hz to ground but also to leave the frequency of the DC to

appear at the output. A load resistor R1 is connected so that a reference to

the ground is maintained. C1, R1 is for bypassing ripples. C2, R2 is used as

a low pass filter, i.e. it passes only low frequency signals and bypasses high

frequency signals. The load resistor should be 1% to 2.5% of the load.

1000f/25V : for the reduction of ripples from the pulsating

10f/25V : for maintaining the stability of the voltage at the load side.

0.1f : for bypassing the high frequency disturbances

BLOCK DIAGRAM FOR POWER SUPPLY

STEP DOWN BRIDGE POSITIVETRANSFORMER RECTIFIER CHARGE

CAPACITOR

5V 12V REGULATOR REGULATOR

MOTHER DISPLAY

BOARD BOARD RELAY

FINISHING AND PAINTING

FINISHING AND PAINTING

JOB PREPARATION:

Before welding, remove any bend in the L angle with the sludge hammer on

the anvil block. Then it is cut to the required length with the hacksaw blade

and fabricated to required dimensional shape with arc welding.

FINISHING OPERATION BEFORE PAINTING:

After welding, any slag on the welded area is removed with the chipping

hammer and cleaned with the metal wire brush. Then all the surfaces are

rubbed with the emery sheet.

Metal primer is applied on the surfaces with the brush. After drying the

metal primer, the second coating is applied with the paint.

CONCLUSION

CONCLUSION

We make this project entirely different from other projects. Since

concepts involved in our project is entirely different that a single unit is used

to various purpose which is not developed by any of other team members.

We have successfully complete this project work at our Institute.

By doing this project work we understood the working principle of

uses of various Brakes, switches, control systems.

Once again we express our sincere thanks to our staff members.

COST ESTIMATION

COST ESTIMATION

1. Electromagnetic coil unit --------- 2100.00

2. brake unit with wheel -------- 1600.00

3. M.s. fabricated stand -------------- 600.00

4. DC power supply 12VDC -------------------------- 900.00

5. Wires, Screws and switch------ 300.00

6. Miscellaneous charges ----------------------------- 200.00------------------- 5900.00

BIBLIOGRAPHY

BIBLIOGRAPHY

“Automotive Braking System” , by Thomas W. birch.

“Automotive Engineering Fundamentals” by Richard Stone,

Jeffrey K. Ball

www.google.com

Automobile engineering ----g.b.s. narang

PHOTO VIEW