of 124
FABRICATION OF MOTORISED HYDRAULIC JACK
THREE AXIS HYDRAULIC MODERN TRAILER
Submitted in partial fulfillment of the requirement for the award of DIPLOMAIN
MECHANICAL ENGINEERING
BY
Under the guidance of ------------------------2005-2006DEPARTMENT OF MECHANICAL ENGINEERING
CERTIFICATE
Register number: _________________________This is to certify that the project report titled THREE AXIS HYDRAULIC MODERN TRAILER submitted by the following students for the award of the Diploma engineering is record of bonafide work carried out by them.
Done by
Mr. /Ms._______________________________
In partial fulfillment of the requirement for the award of Diploma in Mechanical Engineering
During the Year (2005-2006)_________________
_______________
Head of Department
Guide
Coimbatore 641651.
Date:
Submitted for the university examination held on ___________
_________________
________________
Internal Examiner
External Examiner
---------------------------------------------------------------------------------
ACKNOWLEDGEMENT
---------------------------------------------------------------------------------
ACKNOWLEDGEMENT
At this pleasing moment of having successfully completed our project, we wish to convey our sincere thanks and gratitude to the management of our college and our beloved chairman , who provided all the facilities to us.
We would like to express our sincere thanks to our principal , for forwarding us to do our project and offering adequate duration in completing our project.
We are also grateful to the Head of Department Prof. .., for her constructive suggestions & encouragement during our project.
With deep sense of gratitude, we extend our earnest & sincere thanks to our guide .., Department of Mechanical for her kind guidance & encouragement during this project.
We also express our indebt thanks to our TEACHING and NON TEACHING staffs of MECHANICAL ENGINEERING DEPARTMENT,.(COLLEGE NAME).
-------------------------------------------------------------------------------------
THREE AXIS HYDRAULIC MODERN TRAILER -------------------------------------------------------------------------------------
---------------------------------------------------------------------------------
CONTENTS
---------------------------------------------------------------------------------
CONTENTS
CHAPTER NOTITLEPAGE NO
Synopsis
1 Introduction
2 Literature survey
3 Components and Description
4 Battery
5 Microcontroller Unit
6 D.C Motor
7Block Diagram
8Working principle
9 Factors determining choice of Materials
10Advantages and Disadvantages
11 List of materials
12Cost estimation
13Conclusion
Bibliography
Photography
---------------------------------------------------------------------------------
SYNOPSIS---------------------------------------------------------------------------------
SYNOPSIS This project work titled THREE AXIS HYDRAULIC MODERN TRAILER has been conceived having studied the difficulty in unloading the materials. Our survey in the regard in several automobile garages, revealed the facts that mostly some difficult methods were adopted in unloading the materials from the trailer.
Now the project has mainly concentrated on this difficulty, and hence a suitable arrangement has been designed. Such that the vehicles can be unloaded from the trailer in three axes without application of any impact force. By pressing the Direction control valve activated. The oil from the hydraulic oil is goes to the hydraulic cylinder through valve. The ram of the hydraulic cylinder acts as a lifting the trailer cabin.
---------------------------------------------------------------------------------------
Chapter-1
---------------------------------------------------------------------------------------
---------------------------------------------------------------------------------------
INTRODUCTION
---------------------------------------------------------------------------------------
CHAPTER-1INTRODUCTIONAutomation can be achieved through computers, hydraulics, hydraulics, robotics, etc., of these sources, hydraulics form an attractive medium. Automation plays an important role in automobile. Nowadays almost all the automobile vehicle is being atomized in order to product the human being. The automobile vehicle is being atomized for the following reasons.
( To achieve high safety
To reduce man power
To increase the efficiency of the vehicle
To reduce the work load
To reduce the fatigue of workers
To high responsibility
Less Maintenance cost
---------------------------------------------------------------------------------------
Chapter-2---------------------------------------------------------------------------------------
---------------------------------------------------------------------------------------
LITERATURE SURVEY---------------------------------------------------------------------------------------
CHAPTER-2
LITERATURE SURVEY
HYDRAULIC SYSTEM:
In the development of the submarine from pre-war classes, many changes and improvements have occurred. One of the outstanding differences is the large variety of submarine devices which are now operated by hydraulic power. In early classes, there was no hydraulic system, and power requirements were met by means of air or electricity. Along with constantly improving submarine design has gone a constant extension and diversification of the use of hydraulic power. Comparative advantages of hydraulic powerHydraulic systems possess numerous advantages over other systems of power operation. They are light in weight; they are simple and extremely reliable, requiring a minimum of attention and maintenance. Hydraulic controls are sensitive, and afford precise controllability. Because of the low inertia of moving parts, they start and stop in complete obedience to the desires of the operator, and their operation is positive. Hydraulic systems are self-lubricated; consequently there is little wear or corrosion. Their operation is not apt to be interrupted by salt spray or water. Finally, hydraulic units are relatively quiet in operation, an important consideration when detection by the enemy must be prevented.Therefore, in spite of the presence of the two power sources just described, hydraulic power makes its appearance on the submarine because of the fact that its operational advantages, when weighed against the disadvantages enumerated for electricity and air in the preceding paragraphs, fully justify the addition of this third source of power to those available in the modern submarine. FACTORAIRELECTRICITYHYDRAULICS
ReliabilityPoorGoodGood
WeightLightHeavyLight
InstallationSimpleSimpleSimple
Control MechanismValvesSwitches and solenoidsValves
MaintenanceConstant attention necessaryDifficult, requiring skilled personnelSimple
VulnerabilityHigh pressure bottle dangerous; broken lines cause failure and danger to personnel and equipmentGoodSafe; broken lines cause failure
ResponseSlow for both starting and stoppingRapid starting, slow stoppingInstant starting and stopping
ControllabilityPoorFairGood
Quietness of OperationPoorPoorGood
Familiarity of hydraulic principles
For many centuries, man has utilized hydraulic principles to satisfy common, everyday needs, Opening a faucet to fill a sink with water a practical application of hydraulics. Water moves through a dam in accordance with well-known principles of fluid motion. There are hydraulic principles that explain the action of fluids in motion and others for fluids at rest. We are chiefly concerned, however; with that branch of hydromechanics which is called simply Hydraulics and is defined in engineering textbooks as the engineering application of fluid mechanics. It includes the study of the behavior of enclosed liquids under pressure, and the harnessing of the forces existing in fluids to do some practical task such as steering a submarine or opening the outer door of a torpedo tube. Examples of hydraulically operated equipment are familiar to all. Barber or dentist chairs are raised and lowered hydraulically; so is an automobile when placed on a hydraulic rack for a grease job. Stepping on the brake pedal in an automobile creates the hydraulic power which stops the rotation of the four wheels and brings the car to a halt. For an understanding of how a hydraulic system works, we must know the basic principles, or laws, of hydraulics, that is, of confined liquids under pressure.HYDRAULIC COMPONENTS AND DESCRIPTION
A thin bottle is filled to the top with a liquid and tightly corked. A lever is pressed against the cork to apply a downward force. If sufficient pressure is exerted, the bottle will suddenly shatter into a number of pieces, showing that:
Figure 1 Applied pressure is exerted equally in all directions Liquids are practically incompressible.
The applied pressure is transmitted equally in all directions at once.Figure 2 illustrates the application of these principles to a closed hydraulic system. Two cylinders each are having a base whose area is 1 square inch, are connected by a tube. The cylinders are filled with liquid to the level shown, and a piston with a base of the same area (1 square inch) is placed on top of each column of liquid. Then a downward force of 1 pound is applied to one of the pistons. Since this piston has an area of 1 square inch, the pressure upon it is 1 pound per square inch; and since the other piston is of equal area, the same pressure, 1 pound per square inch, will be imposed upward upon it.
Figure 2 Transmission of equal pressures to equal areas Multiple unitsIt is not necessary to confine our system to a single line from the source of hydraulic power. Hydraulic power may be transmitted in many directions to do multiple jobs. Let us connect one cylinder to four others as in Figure 3. Here we apply a force against the piston in the large cylinder. The pressure from the large cylinder is transmitted equally to each of the pistons in the other four cylinders.
Figure 3 multiple units from a single source of powerThis is actually the method of operation of an automobile hydraulic-brake system (see Figure 4). The foot pressure on the brake pedal (1) depresses a piston (2) in the master cylinder (3). Fluid is forced through the lines (4) into each of the brake cylinders (5). At the brake cylinder, two opposed pistons (6) attached to the brake shoes are forced outward, pressing the brake bands (7) against the inside of the wheels (8) to stop their rotation by friction. Removal of the foot pressure allows springs (9) at each wheel to restore the pistons to their original positions and returns the fluid to the master cylinder where it is stored in preparation for the next braking operation.
Figure 4 Automobile hydraulic-brake system
1) Brake pedal; 2) piston; 3) master cylinder; 4) hydraulic line; 5) brake cylinder; 6) brake piston; 7) brake band; 8) wheel; 9) return spring.
A simple hydraulic system
On the basis of the explanation of basic hydraulic principles just given, it is possible to construct a simple, workable hydraulic system which will operate some mechanical device. For example, such a system might open and close a door, and hold it in either position for any desired interval. Basic units of a hydraulic system Such a system is illustrated in Figure 5. It necessarily includes the following basic equipment, which, in one form or another, will be found in every hydraulic system:
A reservoir, or supply tank, containing oil which is supplied to the system as needed and into which the oil from the return line flows.
Figure 5. A simple hydraulic system
A pump, which supplies the necessary working pressure.
A hydraulic cylinder, or actuating cylinder, which uses the hydraulic energy developed in the pump to move the door.
A cut-out valve, by means of which the pressure in the actuating cylinder may be maintained or released as desired.
A check valve, placed in the return line to permit fluid to move in only one direction.
"Hydraulic lines," such as piping or hose, to connect the units to each other. The supply tank must have a capacity large enough to keep the entire system filled with oil and furnish additional oil to make good the inevitable losses from leakage. The tank is vented to the atmosphere; thus atmospheric pressure (14.7 pounds per square inch) forces the oil into the inlet, or suction, side of the pump, in accordance with the principle explained in connection with Figure 3. The tank is generally placed at a higher level than the other units in the system, so that gravity assists in feeding oil into other units.
Single Acting Hydraulic Cylinder:The Single Acting hydraulic cylinder (see Figure 6), which is the simplest type of hydraulic motor, contains a spring-loaded piston, with a piston Rod that extends through one end of the cylinder. In our project, this single acting hydraulic cylinder is used.
Figure 6. Single acting hydraulic cylinderThis piston rod, when connected to the door, supplies the mechanical motion which opens and closes the door. The surface of the piston in contact with the hydraulic fluid has an area of 2 square inches. The cut-out valve is hand-operated. When closed, it shuts off the line between the actuating cylinder and the supply tank, preventing the oil under pressure in the cylinder from escaping into the return line; when opened, it releases this pressure, allowing the loading spring inside the cylinder to expand, and the oil in the cylinder to escape back into the supply tank.A power-driven hydraulic system The door-operating system illustrated in Figure 5 is far simpler than is usually found in actual service. It has the obvious disadvantage that instantaneous opening of the door is not possible because pressure is built up slowly by hand pumping. Units of a power-driven hydraulic systemFigure 7 illustrates a system in which a motor-driven pump is substituted for the hand pump, a double acting actuating cylinder for the spring-loaded single acting cylinder in Figure 5, and including a control valve, an unloading valve, and an automatic relief valve, in addition to the supply tank, or reservoir, and the return line check valve, which are the same as in the first system.
Figure 7. Power-driven hydraulic system
Automatic pumping will give immediate pressure for use at the actuating cylinder whenever it is needed. Double Acting Hydraulic Cylinder:In the simplified system, the door was actuated by a single acting cylinder. Oil was kept in or released from the cylinder by a simple "on-and-off" valve. For more efficient and positive actuation, this will be replaced by a double acting cylinder (see Figure 8). In such a cylinder, the piston can move in either direction to open or close the door.
Figure 8. Double acting hydraulic system The piston is locked in the desired position by the hydraulic fluid, which enters either side of the piston as required and remains there until forced out. Since the flow of the fluid must be directed to either of two sides, a valve, which selects the direction of flow, is installed in the line. This is called a control valve. Control valves vary with the specific application, but generally they are equipped with four ports. Two are connected to the actuating cylinder at either side of the piston. A third port is the pressure port and receives fluid from the pump. The fourth port returns surplus fluid either back to the reservoir or elsewhere in the system. The reciprocating pump The simplest practical application of this principle is seen in the hand-operated reciprocating pump, a simplified version of which is illustrated in Figure 1-15. Here the inlet and outlet ports in the cylinder, or pump body, are both in the same side of the piston. The piston makes a close sliding fit within the cylinder, reducing leakage to a minimum, since excessive leakage destroys the efficiency of a pump. Both the inlet and outlet ports are equipped with check valves which permit the liquid to flow in one direction only, as shown by the arrows.
Figure- Hand-operated reciprocating pump
Assume that the intake side of the pump is connected to a supply of liquid. When we move the piston to the right, lower pressure is created in the chamber formed by the piston. Higher pressure on the fluid outside the chamber forces fluid in through the inlet port and fills the chamber. Moving the handle forward in the opposite direction forces the fluid out. A check valve at the inlet port prevents flow there and, since the fluid must find an outlet somewhere, it is forced out through the discharge port. The check valve at the discharge port prevents the entrance of fluid into the pump on the subsequent suction stroke. The back-and-forth movement of the piston in the pump is referred to as reciprocating motion and this type of pump is generally known as a reciprocating-type piston pump. It may have a single piston or be multi-pistoned. It may be hand-actuated or power-driven. The reciprocating piston principle is conceded to be the most effective for developing high fluid pressures.
---------------------------------------------------------------------------------------
Chapter-3---------------------------------------------------------------------------------------
---------------------------------------------------------------------------------------
COMPONENTS AND DESCRIPTION---------------------------------------------------------------------------------------
CHAPTER-3COMPONENTS AND DESCRIPTION
1. Single acting Hydraulic Cylinder
2. Oil Tank
3. Hydraulic Pump with Motor
4. Solenoid Valve with Control Unit
5. Dash pad and
6. Connectors
7. HOSE COLLAR AND CONNECTOR
8. BEARING WITH BEARING CAP9. WHEEL ARRANGMENT10. TRAILER BODY
1. SINGLE ACTING HYDRAULIC CYLIMDER:
Piston:
The piston is a cylindrical member of certain length which reciprocates inside the cylinder. The diameter of the piston is slightly less than that of the cylinder bore diameter and it is fitted to the top of the piston rod. It is one of the important parts which convert the pressure energy into mechanical power.
The piston is equipped with a ring suitably proportioned and it is relatively soft rubber which is capable of providing good sealing with low friction at the operating pressure. The purpose of piston is to provide means of conveying the pressure of air inside the cylinder to the piston of the oil cylinder.
Generally piston is made up of
Aluminium alloy-light and medium work.
Brass or bronze or CI-Heavy duty.
The piston is single acting spring returned type. The piston moves forward when the high-pressure air is turned from the right side of cylinder. The piston moves backward when the solenoid valve is in OFF condition. The piston should be as strong and rigid as possible. The efficiency and economy of the machine primarily depends on the working of the piston. It must operate in the cylinder with a minimum of friction and should be able to withstand the high compressor force developed in the cylinder and also the shock load during operation.
The piston should posses the following qualities.
a. The movement of the piston not creates much noise.
b. It should be frictionless.
c. It should withstand high pressure.
Piston Rod
The piston rod is circular in cross section. It connects piston with piston of other cylinder. The piston rod is made of mild steel ground and polished. A high finish is essential on the outer rod surface to minimize wear on the rod seals. The piston rod is connected to the piston by mechanical fastening. The piston and the piston rod can be separated if necessary.
One end of the piston rod is connected to the bottom of the piston. The other end of the piston rod is connected to the other piston rod by means of coupling. The piston transmits the working force to the oil cylinder through the piston rod. The piston rod is designed to withstand the high compressive force. It should avoid bending and withstand shock loads caused by the cutting force. The piston moves inside the rod seal fixed in the bottom cover plate of the cylinder. The sealing arrangements prevent the leakage of air from the bottom of the cylinder while the rod reciprocates through it.
Cylinder Cover Plates
The cylinder should be enclosed to get the applied pressure from the compressor and act on the pinion. The cylinder is thus closed by the cover plates on both the ends such that there is no leakage of air. An inlet port is provided on the top cover plate and an outlet ports on the bottom cover plate. There is also a hole drilled for the movement of the piston.
The cylinder cover plate protects the cylinder from dust and other particle and maintains the same pressure that is taken from the compressor. The flange has to hold the piston in both of its extreme positions. The piston hits the top plat during the return stroke and hits the bottom plate during end of forward stroke. So the cover plates must be strong enough to withstand the load.
Cylinder Mounting Plates:
It is attached to the cylinder cover plates and also to the carriage with the help of L bends and bolts.
Cylinder Tube Materials:
LIGHT DUTY
MEDIUM DUTY
HEAVY DUTY1. Plastic
Hard drawn brass tube
hard drawn brass tube.
2. Hard drawn Aluminium Hard drawn steel tube
Aluminium tube Castings tube.
4. Hard drawn Brass, Bronze, Iron or
Brass tube Castings, welded steel tube
End Cover Materials:
LIGHT DUTY MEDIUM DUTY HEAVY DUTY
1. Aluminium stock
Aluminium stock
Hard tensile
(Fabricated)
(Fabricated)
Castings2. Brass stock
Brass stock
(Fabricated)
(Fabricated)
3. Aluminium
Aluminium, Brass,
Castings
iron or steel Castings.
Piston Materials:
LIGHT DUTYMEDIUM DUTYHEAVY DUTY
1.Aluminium
CastingsAluminium Castings
Brass (Fabricated)Aluminium Forgings,
Aluminium Castings.
2.Bronze (Fabricated)Bronze (Fabricated)
3.Iron and Steel
CastingsBrass, Bronze, Iron or
Steel Castings.
Mount Materials:
LIGHT DUTYMEDIUM DUTYHEAVY DUTY
1. Aluminium
CastingsAluminium, Brass
And Steel CastingsHigh Tensile
Steel Castings
2. Light Alloy
(Fabricated)High Tensile
Steel Fabrication
Piston Rod Materials:
MATERIALFINISHREMARKS
MILD STEELGround and polished hardened, ground and polished.Generally preferred chrome plated
STAINLESS STEELGround and PolishedLess scratch resistant than chrome plated piston rod
2. OIL TANK:
The hydraulic system requires the oil to work the system. So we have to provide the oil tank.
Hydraulic fluids Almost any free-flowing liquid is suitable as a hydraulic fluid, as long as it will not chemically injure the hydraulic equipment. For example, an acid, although free-flowing, would obviously be unsuitable because it would corrode the metallic parts of the system. Water, except for its universal availability, suffers from a number of serious defects as a possible hydraulic fluid. One such defect is that it freezes at a relatively high temperature, and, in freezing, expands with tremendous force, destroying pipes and other equipment. Also, it rusts steel parts; and it is rather heavy, creating considerable amount of inertia in a system of any size.The hydraulic fluid used in submarine hydraulic systems is a light, fast-flowing lubricating oil, which does not freeze or even lose its fluidity to any marked degree even at low temperatures, and which possesses the additional advantage of lubricating the internal moving parts of the hydraulic units through which it circulates. Since this oil, a petroleum derivative, causes rapid deterioration of natural rubber, synthetic rubber is specified for use in these systems as packing and oil seals.
3. HYDRAULIC PUMP WITH MOTOR:
In our project, the rotary vacuum pump with motor is used.
The Rotary vacuum pump
The widely used type of pump is the rotary vacuum pump whose operating principle is illustrated bellow. Here the mechanical action which moves the fluid is furnished by the vacuum force.
The oil is trapped by the pump and carried by them around the inside channels of the pump body. This sucks in oil at the inlet port (the left-hand port), and discharges it at the outlet port (the right-hand port). The oil cannot get back through the outer channels to the inlet side of the pump because the vacuum pump is rotating by giving 230Volt A.C supply
Therefore a continuous flow of oil is set up in the direction. This flow continues as long as the vacuum pump continues to rotate. Pumps using the vacuum principle are popular because of their quiet performance and because their simplicity of design results in relative freedom from service troubles.4. SOLENOID VALVE (OR) CUT OFF VALVE:
The Solenoid control valve is used to control the flow direction is called cut off valve or solenoid valve. This solenoid cut off valve is controlled by the electronic control unit which is attached in the dash pad itself.
In our project separate solenoid valve is used for flow direction. One is used to control the oil direction from oil tank to the hydraulic cylinder. Another one is used to return the oil from the hydraulic cylinder to the reservoir.
5. DASH PAD:
The Dash pad contains the Electronic control circuit, and Buttons. The button is activated at the time of we required, the control circuit gives the control signal to the solenoid valve, so that the solenoid valve operate.
6. CONNECTORS:
In our system there are two types of connectors used; one is the hose connector and the other is the reducer.
Hose connectors normally comprise an adapter (connector) hose nipple and cap nut. These types of connectors are made up of brass or Aliminium or hardened steel.
Reducers are used to provide inter connection between two pipes or hoses of different sizes. They may be fitted straight, tee, V or other configurations. These reducers are made up of gunmetal or other materials like hardened steel etc.
7. BEARING WITH BEARING CAP:
The bearings are pressed smoothly to fit into the shafts because if hammered the bearing may develop cracks. Bearing is made upof steel material and bearing cap is mild steel.
INTRODUCTION Ball and roller bearings are used widely in instruments and machines in order to minimize friction and power loss. While the concept of the ball bearing dates back at least to Leonardo da Vinci, their design and manufacture has become remarkably sophisticated. This technology was brought to its present state of perfection only after a long period of research and development. The benefits of such specialized research can be obtained when it is possible to use a standardized bearing of the proper size and type. However, such bearings cannot be used indiscriminately without a careful study of the loads and operating conditions. In addition, the bearing must be provided with adequate mounting, lubrication and sealing. Design engineers have usually two possible sources for obtaining information which they can use to select a bearing for their particular application: a) Textbooks b) Manufacturers Catalogs Textbooks are excellent sources; however, they tend to be overly detailed and aimed at the student of the subject matter rather than the practicing designer. They, in most cases, contain information on how to design rather than how to select a bearing for a particular application. Manufacturers catalogs, in turn, are also excellent and contain a wealth of information which relates to the products of the particular manufacturer. These catalogs, however, fail to provide alternatives which may divert the designers interest to products not manufactured by them. Our Company, however, provides the broadest selection of many types of bearings made by different manufacturers. For this reason, we are interested in providing a condensed overview of the subject matter in an objective manner, using data obtained from different texts, handbooks and manufacturers literature. This information will enable the reader to select the proper bearing in an expeditious manner. If the designers interest exceeds the scope of the presented material, a list of references is provided at the end of the Technical Section. At the same time, we are expressing our thanks and are providing credit to the sources which supplied the material presented here. Construction and Types of Ball Bearings A ball bearing usually consists of four parts: an inner ring, an outer ring, the balls and the cage or separator. To increase the contact area and permit larger loads to be carried, the balls run in curvilinear grooves in the rings. The radius of the groove is slightly larger than the radius of the ball, and a very slight amount of radial play must be provided. The bearing is thus permitted to adjust itself to small amounts of angular misalignment between the assembled shaft and mounting. The separator keeps the balls evenly spaced and prevents them from touching each other on the sides where their relative velocities are the greatest. Ball bearings are made in a wide variety of types and sizes. Single-row radial bearings are made in four series, extra light, light, medium, and heavy, for each bore, as illustrated in Fig. 1-3(a), (b), and (c).
100 Series 200 Series 300 Series Axial Thrust Angular Contact Self-aligning Bearing Fig. 1-3 Types of Ball BearingsThe heavy series of bearings is designated by 400. Most, but not all, manufacturers use a numbering system so devised that if the last two digits are multiplied by 5, the result will be the bore in millimeters. The digit in the third place from the right indicates the series number. Thus, bearing 307 signifies a medium-series bearing of 35-mm bore. For additional digits, which may be present in the catalog number of a bearing, refer to manufacturers details.
Some makers list deep groove bearings and bearings with two rows of balls. For bearing designations of Quality Bearings & Components (QBC), see special pages devoted to this purpose. The radial bearing is able to carry a considerable amount of axial thrust. However, when the load is directed entirely along the axis, the thrust type of bearing should be used. The angular contact bear- ing will take care of both radial and axial loads. The self-aligning ball bearing will take care of large amounts of angular misalignment. An increase in radial capacity may be secured by using rings with deep grooves, or by employing a double-row radial bearing. Radial bearings are divided into two general classes, depending on the method of assembly. These are the Conrad, or nonfilling-notch type, and the maximum, or filling-notch type. In the Conrad bearing, the balls are placed between the rings as shown in Fig. 1-4(a). Then they are evenly spaced and the separator is riveted in place. In the maximum-type bearing, the balls are a (a) (b) (c) (d) (e) (f) 100 Series Extra Light 200 Series Light 300 Series Medium Axial Thrust Bearing Angular Contact Bearing Self-aligning Bearing Fig. 1-3 Types of Ball Bearings Fig. 1-4 Methods of Assembly for Ball Bearings (a) Conrad or non-filling notch type (b) Maximum or filling notch type8. WHEEL ARRANGEMENT:
The wheels are fitted to the body of the vehicle with the help of end bearing and bearing caps. The wheels are made up of fiber material.
9. TRAILER BODY:-
The trailer body is made up of mild steel sheet metal. This frame is look like a small model trailer. ---------------------------------------------------------------------------------------
Chapter-4---------------------------------------------------------------------------------------
--------------------------------------------------------------------------------------
BATTERY--------------------------------------------------------------------------------------
CHAPTER-4
BATTERY
INTRODUCTION:
In isolated systems away from the grid, batteries are used for storage of excess solar energy converted into electrical energy. The only exceptions are isolated sunshine load such as irrigation pumps or drinking water supplies for storage. In fact for small units with output less than one kilowatt. Batteries seem to be the only technically and economically available storage means. Since both the photo-voltaic system and batteries are high in capital costs. It is necessary that the overall system be optimized with respect to available energy and local demand pattern. To be economically attractive the storage of solar electricity requires a battery with a particular combination of properties:
(1) Low cost
(2) Long life
(3) High reliability(4) High overall efficiency
(5) Low discharge
(6) Minimum maintenance
(A) Ampere hour efficiency
(B) Watt hour efficiencyWe use lead acid battery for storing the electrical energy from the solar panel for lighting the street and so about the lead acid cells are explained below.
LEAD-ACID WET CELL:Where high values of load current are necessary, the lead-acid cell is the type most commonly used. The electrolyte is a dilute solution of sulfuric acid (HSO). In the application of battery power to start the engine in an auto mobile, for example, the load current to the starter motor is typically 200 to 400A. One cell has a nominal output of 2.1V, but lead-acid cells are often used in a series combination of three for a 6-V battery and six for a 12-V battery.
The lead acid cell type is a secondary cell or storage cell, which can be recharged. The charge and discharge cycle can be repeated many times to restore the output voltage, as long as the cell is in good physical condition. However, heat with excessive charge and discharge currents shortends the useful life to about 3 to 5 years for an automobile battery. Of the different types of secondary cells, the lead-acid type has the highest output voltage, which allows fewer cells for a specified battery voltage.
CONSTRUCTION:
Inside a lead-acid battery, the positive and negative electrodes consist of a group of plates welded to a connecting strap. The plates are immersed in the electrolyte, consisting of 8 parts of water to 3 parts of concentrated sulfuric acid. Each plate is a grid or framework, made of a lead-antimony alloy. This construction enables the active material, which is lead oxide, to be pasted into the grid. In manufacture of the cell, a forming charge produces the positive and negative electrodes. In the forming process, the active material in the positive plate is changed to lead peroxide (pbo). The negative electrode is spongy lead (pb).
Automobile batteries are usually shipped dry from the manufacturer. The electrolyte is put in at the time of installation, and then the battery is charged to from the plates. With maintenance-free batteries, little or no water need be added in normal service. Some types are sealed, except for a pressure vent, without provision for adding water.
The construction parts of battery are shown in figure (6).CHEMICAL ACTION:Sulfuric acid is a combination of hydrogen and sulfate ions. When the cell discharges, lead peroxide from the positive electrode combines with hydrogen ions to form water and with sulfate ions to form lead sulfate. Combining lead on the negative plate with sulfate ions also produces he sulfate. There fore, the net result of discharge is to produce more water, which dilutes the electrolyte, and to form lead sulfate on the plates.As the discharge continues, the sulfate fills the pores of the grids, retarding circulation of acid in the active material. Lead sulfate is the powder often seen on the outside terminals of old batteries. When the combination of weak electrolyte and sulfating on the plate lowers the output of the battery, charging is necessary.On charge, the external D.C. source reverses the current in the battery. The reversed direction of ions flows in the electrolyte result in a reversal of the chemical reactions. Now the lead sulfates on the positive plate reactive with the water and sulfate ions to produce lead peroxide and sulfuric acid. This action re-forms the positive plates and makes the electrolyte stronger by adding sulfuric acid. At the same time, charging enables the lead sulfate on the negative plate to react with hydrogen ions; this also forms sulfuric acid while reforming lead on the negative plate to react with hydrogen ions; this also forms currents can restore the cell to full output, with lead peroxide on the positive plates, spongy lead on the negative plate, and the required concentration of sulfuric acid in the electrolyte. The chemical equation for the lead-acid cell is
Charge
Pb + pbO + 2HSO 2pbSO + 2HO
Discharge
On discharge, the pb and pbo combine with the SO ions at the left side of the equation to form lead sulfate (pbSO) and water (HO) at the right side of the equation. One battery consists of 6 cell, each have an output voltage of 2.1V, which are connected in series to get an voltage of 12V and the same 12V battery is connected in series, to get an 24 V battery. They are placed in the water proof iron casing box.
CARING FOR LEAD-ACID BATTERIES:
Always use extreme caution when handling batteries and electrolyte. Wear gloves, goggles and old clothes. Battery acid will burn skin and eyes and destroy cotton and wool clothing.The quickest way of ruin lead-acid batteries is to discharge them deeply and leave them stand dead for an extended period of time. When they discharge, there is a chemical change in the positive plates of the battery. They change from lead oxide when charge out lead sulfate when discharged. If they remain in the lead Sulfate State for a few days, some part of the plate dose not returns to lead oxide when the battery is recharged. If the battery remains discharge longer, a greater amount of the positive plate will remain lead sulfate. The parts of the plates that become sulfate no longer store energy. Batteries that are deeply discharged, and then charged partially on a regular basis can fail in less then one year. Check your batteries on a regular basis to be sure they are getting charged. Use a hydrometer to check the specific gravity of your lead acid batteries. If batteries are cycled very deeply and then recharged quickly, the specific gravity reading will be lower than it should because the electrolyte at the top of the battery may not have mixed with the charged electrolyte. Check the electrolyte level in the wet-cell batteries at the least four times a year and top each cell of with distilled water. Do not add water to discharged batteries. Electrolyte is absorbed when batteries are very discharged. If you add water at this time, and then recharge the battery, electrolyte will overflow and make a mess.
Keep the top of your batteries clean and check that cables are tight. Do not tighten or remove cables while charging or discharging. Any spark around batteries can cause a hydrogen explosion inside, and ruin one of the cells, and you.
On charge, with reverse current through the electrolyte, the chemical action is reversed. Then the pb ions from the lead sulfate on the right side of the equation re-form the lead and lead peroxide electrodes. Also the SO ions combine with H ions from the water to produce more sulfuric acid at the left side of the equation.
CURRENT RATINGS:
Lead-acid batteries are generally rated in terms of how much discharge currents they can supply for a specified period of time; the output voltage must be maintained above a minimum level, which is 1.5 to 1.8V per cell. A common rating is ampere-hours (A.h.) based on a specific discharge time, which is often 8h. Typical values for automobile batteries are 100 to 300 A.h.
As an example, a 200 A.h battery can supply a load current of 200/8 or 25A, used on 8h discharge. The battery can supply less current for a longer time or more current for a shorter time. Automobile batteries may be rated for cold cranking power, which is related to the job of starting the engine. A typical rating is 450A for 30s at a temperature of 0 degree F.Note that the ampere-hour unit specifies coulombs of charge. For instance, 200 A.h. corresponds to 200A*3600s (1h=3600s). the equals 720,000 A.S, or coulombs. One ampere-second is equal to one coulomb. Then the charge equals 720,000 or 7.2*10^5C. To put this much charge back into the battery would require 20 hours with a charging current of 10A.The ratings for lead-acid batteries are given for a temperature range of 77 to 80F. Higher temperature increase the chemical reaction, but operation above 110F shortens the battery life.Low temperatures reduce the current capacity and voltage output. The ampere-hour capacity is reduced approximately 0.75% for each decreases of 1 F below normal temperature rating. At 0F the available output is only 60 % of the ampere-hour battery rating. In cold weather, therefore, it is very important to have an automobile battery unto full charge. In addition, the electrolyte freezes more easily when diluted by water in the discharged condition.
SPECIFIC GRAVITY:Measuring the specific gravity of the electrolyte generally checks the state of discharge for a lead-acid cell. Specific gravity is a ratio comparing the weight of a substance with the weight of a substance with the weight of water. For instance, concentrated sulfuric acid is 1.835 times as heavy as water for the same volume. Therefore, its specific gravity equals 1.835. The specific gravity of water is 1, since it is the reference.
In a fully charged automotive cell, mixture of sulfuric acid and water results in a specific gravity of 1.280 at room temperatures of 70 to 80F. As the cell discharges, more water is formed, lowering the specific gravity. When it is down to about 1.150, the cell is completely discharged.
Specific-gravity readings are taken with a battery hydrometer. Note that the calibrated float with the specific gravity marks will rest higher in an electrolyte of higher specific gravity. The decimal point is often omitted for convenience. For example, the value of 1.220 is simply read twelve twenty. A hydrometer reading of 1260 to 1280 indicates full charge, approximately 12.50 are half charge, and 1150 to 1200 indicates complete discharge.
The importance of the specific gravity can be seen from the fact that the open-circuit voltage of the lead-acid cell is approximately equal to
V=Specific gravity + 0.84
For the specific gravity of 1.280, the voltage is 1.280 = 0.84 = 2.12V, as an example. These values are for a fully charged battery.
CHARGING THE LEAD-ACID BATERY:
The requirements are illustrated in figure. An external D.C. voltage source is necessary to produce current in one direction. Also, the charging voltage must be more than the battery e.m.f. Approximately 2.5 per cell are enough to over the cell e.m.f. so that the charging voltage can produce current opposite to the direction of discharge current. Note that the reversal of current is obtained just by connecting the battery VB and charging source VG with + to + and to-, as shown in figure. The charging current is reversed because the battery effectively becomes a load resistance for VG when it higher than VB. In this example, the net voltage available to produce charging currents is 15-12=3V. A commercial charger for automobile batteries is essentially a D.C. power supply, rectifying input from the AC power line to provide D.C. output for charging batteries.
Float charging refers to a method in which the charger and the battery are always connected to each other for supplying current to the load. In figure the charger provides current for the load and the current necessary to keep the battery fully charged. The battery here is an auxiliary source for D.C. power.
It may be of interest to note that an automobile battery is in a floating-charge circuit. The battery charger is an AC generator or alternator with rectifier diodes, driver by a belt from the engine. When you start the car, the battery supplies the cranking power. Once the engine is running, the alternator charges he battery. It is not necessary for the car to be moving. A voltage regulator is used in this system to maintain the output at approximately 13 to 15 V.
The constant voltage of 24V comes from the solar panel controlled by the charge controller so for storing this energy we need a 24V battery so two 12V battery are connected in series. It is a good idea to do an equalizing charge when some cells show a variation of 0.05 specific gravity from each other. This is a long steady overcharge, bringing the battery to a gassing or bubbling state. Do not equalize sealed or gel type batteries. With proper care, lead-acid batteries will have a long service life and work very well in almost any power system. Unfortunately, with poor treatment lead-acid battery life will be very short.
---------------------------------------------------------------------------------------
Chapter-5---------------------------------------------------------------------------------------
--------------------------------------------------------------------------------------
MICRO CONTROLLER--------------------------------------------------------------------------------------
CHAPTER-5
MICRO CONTROLLER
INTRODUCTION
A Micro controller consists of a powerful CPU tightly coupled with memory (RAM, ROM or EPROM), various I/O features such as serial ports, parallel ports, Timer / Counters, Interrupt Controller, Data Acquisition interfaces-Analog to Digital Converter (ADC), Digital to Analog Converter (DAC), everything integrated into a single silicon chip.
It does not mean that any micro controller should have all the above said features on chip, Depending on the need and area of application for which it is designed, the on chip features present in it may or may not include all the individual section said above.
Any Microcomputer system requires memory to store a sequence of instruction making up a program, parallel port or serial port for communicating with an external system, timer / counter for control purposes like generating time delays, Baud rate for the serial port, apart from the controlling unit called the Central Processing Unit.
PIN DIAGRAM OF IC AT89C52:
PIN DESCRIPTION:
VCC ---- Supply voltage.
GND ---- Ground.
Port 0
Port 0 is an 8-bit open-drain bi-directional I/O port. When 1s are written to port 0 pins, the pins can be used as high impedance inputs.
Port 1
Port 1 is an 8-bit bi-directional I/O port with internal pull-ups. When 1s are written to Port 1 pins they are pulled high by the internal pull-ups and can be used as inputs. Port 1 also receives the low-order address bytes during flash programming and verification.
Port 2
Port 2 is an 8-bit bi-directional I/O port with internal pull-ups. Port 2 emits the high-order address byte during fetches from external program memory and during accesses to external data memory that use 16-bit addresses (MOVX @ DPTR).
Port 3
Port 3 is an 8-bit bi-directional I/O port with internal pull-ups. The Port 3 output buffers can sink/source four TTL inputs. When 1s are written to Port 3 pins they are pulled high by the internal pull-ups and can be used as inputs. These ports can be used as following various features.
Port Pin
Alternate Functions
P3.0
RXD (serial input port)
P3.1
TXD (serial output port)
P3.2
INT0 (external interrupt 0)
P3.3
INT1 (external interrupt 1)
P3.4
T0 (timer 0 external input)
P3.5
T1 (timer 1 external input)
P3.6
WR (external data memory
Write strobe)
P3.7
RD (external data memory
Read strobe)
RST
Reset input. A high on this pin for two machine cycles while the oscillator is running resets the device.
ALE/PROG
(PROG) during Flash programming. Address Latch Enable output pulse for latching the low byte of the address during accesses to external memory. This pin is also the program pulse input
PSEN
Program Store Enable is the read strobe to external program memory. When the AT89C51 is executing code from external program memory, PSEN is activated twice each machine cycle, except that two PSEN activations are skipped during each access to external data memory.
EA/VPP
External Access Enable. EA must be strapped to GND in order to enable the device to fetch code from external program memory locations starting at 0000H up to FFFFH. Note, however, that if lock bit 1 is programmed, EA will be internally latched on reset. EA should be strapped to VCC for internal program executions. This pin also receives the 12-volt programming enable voltage (VPP) during Flash programming, for parts that require 12-volt VPP.
XTAL1
Input to the inverting oscillator amplifier and input to the internal clock operating circuit.
XTAL2
-Output from the inverting Oscillator amplifier.
INTERNAL RAM STRUCTURE:
The programming model of the 89C51 of the 89C51 as a collection of 8 and 16-bit registers and 8-bit memory locations. These registers and memory locations can be made to operate using the software instructions that are incorporated as part of the design. The program instructions have to do with the control of the registers and digital data paths that are physically located outside the 89C51.
The number of special-purpose registers that must be present to make a microcomputer a micro controller complicates the model. A cursory inspection of the model is recommended for the first time viewer, return to the model as needed while progressing through the remainder of the text.
Most of the registers have a specific function, those that do occupy an individual block with a symbolic name, such as A or TH0 or PC, others, which are generally indistinguishable from each other, are grouped in a larger block, such as internal ROM or RAM memory.
Each register, with the exception of the program counter, has an internal 1-byte address assigned to it.
Some registers marked with an asterisk are both byte and bit addressable. That is, the entire byte of data at such register address may be read or altered, or individual bits may be read or altered. Software instructions are generally able to specify a register by its address, its symbolic name, or both.
A pin out of the 89C51 packaged in a 40-pin DIP. It is important to note that many of the pins are used for more than one function. Not all of the possible 89C51 features may be used at the same time.
Programming instructions or physical pin connections determine the use of any multifunction pins. For example, port 3 bit 0 may be used as a general-purpose I/O pin, or as an input (RXD) to SBUF, the serial data receiver register.
The system designers decide which of these two functions is to be used and design the hardware and software affecting that pin accordingly.
THE 89C51 OSCILLATOR AND CLOCK:
The heart of the 89C51 is the circuitry that generates the clock pulses by which all internal operations are synchronized. Pins XTAL1 and XTAL2 are provided for connecting resonant network to form an oscillator.
Typically, a quartz crystal and capacitors are employed. The crystal frequency is the basic internal clock frequency of the micro controller. The manufacturers make available 89C51 designs that can run at specified maximum and minimum frequencies, typically 1 MHz to 16 Mhz. Minimum frequencies imply that some internal memories are dynamic and must always operate above a minimum frequency or data will be lost.
Serial data communication needs often dictate the frequency of the oscillator because of the requirement that internal counters must divide the basic clock rate to yield standard communication bit per second rates. If the basic clock frequency is not divisible without a remainder, then the resulting communication frequency is not standard.
Ceramic resonators may be used as a low cost alternative to crystal resonators. However, decreases in frequency stability and accuracy make the ceramic resonator a poor choice if high speed serial data communication with other systems, or critical timing, is to be done.
The oscillator formed by the crystal, capacitors, and an on-chip inverter generates a pulse train at the frequency of the crystal. The clock frequency, f, establishes the smallest interval of time within the micro controller, called the pulse, p, time.
The smallest interval of times within the complies any simple instruction, or part of a complex instruction, however, is the machine cycle. The machine cycle is itself made up of micro controller such as fetching an output code byte, decoding an output code, executing an output code, or writing a data byte. Two oscillator pulses define each state.
Program instructions may require one, two or four machine cycles to be executed, depending on the type of instruction will take to be executed find the number of cycles, C, from the list in Appendix A. The time to execute that instruction is then found by multiplying C by 12 and dividing the product by the crystal frequency.
Tinst = C x 12d / Crystal frequency
For example, if the crystal frequency is 16MHz, then the time to execute an ADD A, R1 one cycle instruction is 75 microseconds. A 12MHz crystal yields the convenient time of 1 microsecond per cycle. An 11.0592MHz crystal, although seemingly an odd value, yields a cycle frequency of 921.6 KHz, which can be divided evenly by the standard communication baud rates of 19200, 9600, 4800, 2400 and 300Hz.
Note, there are two ALE pulses per machine cycle. The ALE pulse, which is primarily used as a timing pulse for external memory access, indicates when every instruction byte is fetched. Two bytes of a single instruction may thus be fetched, and executed, in one machine cycle. Single byte instructions are not executed in a half cycle, however. Single byte instructions throw away the second byte. The next instruction is then fetched in the following cycle.
PROGRAM COUNTER AND DATA POINTER:
The 89C51 contains two 16-bit registers: the program counters (PC) and the data pointer (DPTR). Each is used to hold the address of a bute in memory.
Program instruction bytes are fetched from locations in memory that are addressed by the PC. Program ROM may be on the chip at addresses 0000h to 0FFFh, external to the chip for addresses that exceed 0FFFh, or totally external by certain instructions. The PC is the only register that does not have an internal address.
The DPTR register is made up of two 8-bit registers, named DPH and DPL, which are used to furnish memory addresses for internal and external code access and external data access.
The DPTR is under the control of program instructions and can be specified by its 16-bit name, DPTR, or by each individual byte name, DPH and DPTR does not have a single internal address, DPH and DPL are each assigned an address.
ADVANTAGES OF MICRO CONTROLLERS:
1. If a system is developed with a microprocessor, the designer has to go for external memory such as RAM, ROM, or EPROM and peripherals and hence the size of the PCB will be large enough to hold all the peripheral facilities on a single chip so development of a similar system with a micro controller reduces PCB size and cost of the design.
2. One of the major difference between a Micro controller and a Micro controller and a Micro processor is that a controller often deals with bits, not bytes as in the real world application, for example switch contacts can only be open or close, indicators should be lit or dark and motors can be either turned on or off and so forth.
3. The Micro controller has two 16 bit timer / counters built within it, which makes it more suitable to this application since we need to produce some accurate timer delays. It is even advantageous that the timers also act as interrupt.
The Major Features of 8-bit Micro Controller ATMEL 89C51
1. 8 bit CPU optimized for control applications
2. Extensive Boolean processing (single-bit logic) capabilities.
3. On-chip flash program memory.
4. On-chip data RAM
5. Bi-directional and individually addressable I/O Lines
6. Multiple 16-bit timer/counters
7. On-chip Oscillator and clock circuitry
8. On-chip EEPROM
9. SPI serial bus interface
10. Watch Dog Timer
POWER MODES OF ATMEL 89C51 MICRO CONTROLLER:
To exploit the power savings available in CMOS circuitry. Atmels Flash micro controllers have two software-invited reduced power modes.
IDLE MODE:
The CPU is turned off while the RAM and other on-chip peripherals continue operating. In this mode current draw is reduced to about 15 percent of the current drawn when the device is fully active.
POWER DOWN MODE:
All on-chip activities are suspended while the on-chip RAM continues to hold its data. In this mode, the device typically draws less than 15 A and can be as low as 0.6 A.
POWER ON RESET:
When power is turned on, the circuit holds the RST pin high for an amount of time that depends on the capacitor value and the rate at which it charges.
To ensure a valid reset, the RST pin must be held high long enough to allow the oscillator to start up plus two machine cycles.
PROGRAM MEMORY:
The map of the lower part of the program memory, after reset, the CPU begins execution from location 0000h.
As shown each interrupt is assigned a fixed location in program memory. The interrupt causes the CPU to jump to that location, where it executes the service routine. External interrupt 0 for examples assigned to location 00003h. If the interrupt in not used its service location is available as general-purpose program memory.
The interrupt service locations are spaced at 8 byte intervals 00003h for external interrupt 0, 000Bh for Timer 0, 0013h for external interrupt 1,001Bh for Timer 1, and so on. If an interrupt service routine is short enough (as is often the case in control applications) it can reside entirely within that 8-byte interval. Longer service routines can use a jump instruction to skip over subsequent interrupt locations if other interrupts are in use.
The lowest addresses of program memory can be either in the on-chip flash or in an external memory. To make this selection, strap the External Access (EA) pin to either VCC or GND.
For example, in the AT89C51 with 4K bytes of on-chip Flash, if the EA pin is strapped to Vcc, program fetches to addresses 0000h through 0FFFh are directed to internal flash program fetches to addresses 0000h through 0FFFFh are directed to internal flash program fetches to addresses 10000h through FFFFh are directed to external memory.
DATA MEMORY
The internal data memory is divided into three blocks namely,
1. The lower 128 bytes of internal RAM
2. The upper 128 bytes of internal RAM
3. Special function registers.
Internal data memory addresses are always 1 byte wide, which implies an address space of only 256 bytes. However, the addressing modes for internal RAM can in fact accommodate 384bytes. Direct addresses higher than 7FH access one memory space and indirect addresses higher 7FH access a different memory space.
The lowest 32 bytes are grouped into 4 banks of 8 registers. Program instructions call out these registers as R0 through R7. Two bits in the program status word (PSW) select, which register bank, is in use. This architecture allows more efficient use of code space, since register instructions are shorter than instructions that use direct addressing.
The next 16-bytes above the register banks form a block of bit addressable memory space. The micro controller instruction set includes a wide selection of single-bit instruction set includes a wide selection of single-bit instructions and this instruction can directly address the 128 bytes in this area. These bit addresses are 00h through 7Fh.
PROGRAM STATUS WORD:
CYACFORS1RS0OV---P
Program status word register in ATMEL 89C51 is given below
S
PSW0:
Priority of accumulator is set by hard ware to 1 if it contains and odd number of 1s; otherwise it is reset to zero.
PSW1:
User definable flag.
PSW2:
Over flow flag set by arithmetic operations
PSW3 & PSW 4:
Register bank select
PSW5:
General purpose flag
PSW6:
Auxiliary carries flag
PSW7:
Parity bit.
---------------------------------------------------------------------------------------
Chapter-6---------------------------------------------------------------------------------------
---------------------------------------------------------------------------------------
D.C MOTOR---------------------------------------------------------------------------------------
CHAPTER-6
D.C MOTORThe electrical motor is an instrument, which converts electrical energy into mechanical energy. According to faradays law of Electro magnetic induction, when a current carrying conductor is placed in a magnetic field, it experiences a mechanical force whose direction is given by Flemings left hand rule.Constructional a dc generator and a dc motor are identical. The same dc machine can be used as a generator or as a motor. When a generator is in operation, it is driven mechanically and develops a voltage. The voltage is capable of sending current through the load resistance. While motor action a torque is developed.
The torque can produce mechanical rotation. Motors are classified as series wound, shunt wound motors.
Principles of operation:
The basic principle of Motor action lies in a sample sketch.
Movement of
Conductor
Magnetic flux
Current carrying
Conductor
The motor runs according to the principle of Flemings left hand rule. When a current carrying conductor is placed in a magnetic field is produced to move the conductor away from the magnetic field.
The conductor carrying current to North and South poles is being removed. In the above stated two conditions there is no movement of the conductors. Whenever a current carrying conductor is placed in a magnetic field. The field due to the current in the conductor but opposes the main field below the conductor. As a result the flux density below the conductor. It is found that a force acts on the conductor to push the conductor downwards.
If the current in the conductor is reversed, the strengthening of the flux lines occurs below the conductor, and the conductor will be pushed upwards.
As stated above the coil side A will be forced to move downwards, where as the coil side B will be forced to move upwards. The forces acting on the coil sides A and B will be the same coil magnitudes, but their directions will be opposite to one another. In DC machines coils are wound on the armature core, which is supported by the bearings, enhances rotation of the armature. The commutator periodically reverses the direction of current flow through the armature. Thus the armature rotates continuously.
An electric motor is all about magnets and magnetism: a motor uses magnets to create motion. If you have ever played with magnets you know about the fundamental law of all magnets: Opposites attract and likes repel. So if you have 2 bar magnets with their ends marked north and south, then the North end of one magnet will attract the South end of the other. On the other hand, the North end of one magnet will repel the North end of the other (and similarly south will repel south). Inside an electric motor these attracting and repelling forces create rotational motion. In the diagram above and below you can see two magnets in the motor, the armature (or rotor) is an electromagnet, while the field magnet is a permanent magnet (the field magnet could be an electromagnet as well, but in most small motors it is not to save power). Electromagnets and Motors:
To understand how an electric motor works, the key is to understand how the electromagnet works. An electromagnet is the basis of an electric motor. You can understand how things work in the motor by imagining the following scenario. Say that you created a simple electromagnet by wrapping 100 loops of wire around a nail and connecting it to a battery. The nail would become a magnet and have a North and South pole while the battery is connected. Now say that you take your nail electromagnet, run an axle through the middle of it, and you suspended it in the middle of a horseshoe magnet as shown in the figure below. If you were to attach a battery to the electromagnet so that the North end of the nail appeared as shown, the basic law of magnetism tells you what would happen: The North end of the electromagnet would be repelled from the north end of the horseshoe magnet and attracted to the south end of the horseshoe magnet. The South end of the electromagnet would be repelled in a similar way. The nail would move about half a turn and then stop in the position shown.
You can see that this half-turn of motion is simple and obvious because of the way magnets naturally attract and repel one another. The key to an electric motor is to then go one step further so that, at the moment that this half-turn of motion completes, the field of the electromagnet flips. The flip causes the electromagnet to complete another half-turn of motion. You flip the magnetic field simply by changing the direction of the electrons flowing in the wire (you do that by flipping the battery over). If the field of the electromagnet flipped at just the right moment at the end of each half-turn of motion, the electric motor would spin freely. The Armature:
The armature takes the place of the nail in an electric motor. The armature is an electromagnet made by coiling thin wire around two or more poles of a metal core. The armature has an axle, and the commutator is attached to the axle. In the diagram above you can see three different views of the same armature: front, side and end-on. In the end-on view the winding is eliminated to make the commutator more obvious. You can see that the commutator is simply a pair of plates attached to the axle. These plates provide the two connections for the coil of the electromagnet.The Commutator and brushes:
The "flipping the electric field" part of an electric motor is accomplished by two parts: the commutator and the brushes. The diagram at the right shows how the commutator and brushes work together to let current flow to the electromagnet, and also to flip the direction that the electrons are flowing at just the right moment. The contacts of the commutator are attached to the axle of the electromagnet, so they spin with the magnet. The brushes are just two pieces of springy metal or carbon that make contact with the contacts of the commutator. Putting It All Together:When you put all of these parts together, what you have is a complete electric motor:
In this figure, the armature winding has been left out so that it is easier to see the commutator in action. The key thing to notice is that as the armature passes through the horizontal position, the poles of the electromagnet flip. Because of the flip, the North pole of the electromagnet is always above the axle so it can repel the field magnet's North pole and attract the field magnet's South pole. If you ever take apart an electric motor you will find that it contains the same pieces described above: two small permanent magnets, a commutator, two brushes and an electromagnet made by winding wire around a piece of metal. Almost always, however, the rotor will have three poles rather than the two poles as shown in this article. There are two good reasons for a motor to have three poles:
It causes the motor to have better dynamics. In a two-pole motor, if the electromagnet is at the balance point, perfectly horizontal between the two poles of the field magnet when the motor starts; you can imagine the armature getting "stuck" there. That never happens in a three-pole motor. Each time the commutator hits the point where it flips the field in a two-pole motor, the commutator shorts out the battery (directly connects the positive and negative terminals) for a moment. This shorting wastes energy and drains the battery needlessly. A three-pole motor solves this problem as well. It is possible to have any number of poles, depending on the size of the motor and the specific application it is being used in. ---------------------------------------------------------------------------------------
Chapter-7---------------------------------------------------------------------------------------
---------------------------------------------------------------------------------------
BLOCK DIAGRAM---------------------------------------------------------------------------------------
CHAPTER-7BLOCK DIAGRAM
---------------------------------------------------------------------------------------
Chapter-8---------------------------------------------------------------------------------------
---------------------------------------------------------------------------------------
WORKING PRINCIPLE---------------------------------------------------------------------------------------
CHAPTER-8WORKING PRINCIPLEPRINCIPLE:
Some of the general properties of liquids in open containers have been described. It remains to discuss how a liquid will behave when confined, for, example, in an enclosed hydraulic system.
Liquids are practically incompressible. The following two basic principles will help to explain the behavior of liquids when enclosed: Liquids are practically incompressible in the pressure ranges being considered. Stated simply, this means that a liquid cannot be squeezed into a smaller space than it already occupies.
Therefore, an increase in pressure on any part of a confined liquid is transmitted undiminished in all directions throughout the liquid (Pascal's principle). For example, if pressure is applied at one end of a long pipe, the liquid, being practically incompressible, will transmit the pressure equally to every portion of the pipe.
WORKING OPERATION:-
The dash pad switch was activated at the time of any unloading condition. The control signal is given to the solenoid valve, when the button is activated. The same time, the motor is started which is coupled with rotary hydraulic pump. The oil is suctioned from the oil tank and compressed oil goes to the solenoid valve.
The solenoid valve is activated at the time of dash pad button ON. The compressed fluid (oil) goes to the hydraulic cylinder. The compressed oil pusses the hydraulic cylinder piston and move forward. The RAM is fixed at the end of the single acting hydraulic cylinder. The piston moves towards upward and the ram is lifting the tray.
The solenoid valve is deactivated at the time of dash pad button OFF. The hydraulic cylinder fluid (oil) goes to the solenoid valve. Then the oil returns back to the oil tank, by the time of deactivating the solenoid valve. Thus the extra oil not required to maintain the oil level in the oil tank. ---------------------------------------------------------------------------------------
Chapter-9---------------------------------------------------------------------------------------
---------------------------------------------------------------------------------------
FACTORS DETERMINING THE CHOICE OF MATERIALS---------------------------------------------------------------------------------------
CHAPTER-9FACTORS DETERMINING THE CHOICE OF MATERIALS
The various factors which determine the choice of material are discussed below.
1. Properties:
The material selected must posses the necessary properties for the proposed application. The various requirements to be satisfied can be weight, surface finish, rigidity, ability to withstand environmental attack from chemicals, service life, reliability etc.
The following four types of principle properties of materials decisively affect their selection
a. Physical
b. Mechanical
c. From manufacturing point of view
d. Chemical
The various physical properties concerned are melting point, Thermal Conductivity, Specific heat, coefficient of thermal expansion, specific gravity, electrical Conductivity, Magnetic purposes etc.
The various Mechanical properties Concerned are strength in tensile, compressive shear, bending, torsional and buckling load, fatigue resistance, impact resistance, elastic limit, endurance limit, and modulus of elasticity, hardness, wear resistance and sliding properties.
The various properties concerned from the manufacturing point of view are.
Cast ability,
weld ability,
Brazability,
forge ability,
merchantability,
surface properties,
shrinkage,
Deep drawing etc.
2. Manufacturing Case:
Sometimes the demand for lowest possible manufacturing cost or surface qualities obtainable by the application of suitable coating substances may demand the use of special materials.
3. Quality Required:
This generally affects the manufacturing process and ultimately the material. For example, it would never be desirable to go for casting of a less number of components which can be fabricated much more economically by welding or hand forging the steel.
4. Availability of Material:
Some materials may be scarce or in short supply. It then becomes obligatory for the designer to use some other material which though may not be a perfect substitute for the material designed.
The delivery of materials and the delivery date of product should also be kept in mind.
5. Space Consideration:
Sometimes high strength materials have to be selected because the forces involved are high and the space limitations are there.
6. Cost:
As in any other problem, in selection of material the cost of material plays an important part and should not be ignored.
Some times factors like scrap utilization, appearance, and non-maintenance of the designed part are involved in the selection of proper materials.
---------------------------------------------------------------------------------------
Chapter-10---------------------------------------------------------------------------------------
---------------------------------------------------------------------------------------
ADVANTAGES , DISADVANTAGES AND APPLICATIONS---------------------------------------------------------------------------------------
CHAPTER-10ADVANTAGES, DISADVANTAGES AND APPLICATIONSADVANTAGES It requires simple maintenance cares
Checking and cleaning are easy, because of the main parts are screwed.
Handling is easy.
Manual power not required
Repairing is easy.
Replacement of parts is easy.
DISADVANTAGES
1. Initial cost is high.
2. Separate air tank or compressor is required.APPLICATIONS All hydraulic trailers---------------------------------------------------------------------------------------
Chapter-11------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
LIST OF MATERIALS---------------------------------------------------------------------------------------
CHAPTER-11LIST OF MATERIALS
Sl. No.PARTSQty.Material
i.Hydraulic Double Acting Cylinder2M.S
ii.3/2 solenoid Direction Control Valve2Aluminium
iii.Microcontroller Unit1Electronics
iv.Wheel4Rubber
v.Bearing with Bearing Cap4Fiber
vi.Polyethylene Tube-Polyurethene
vii.Hose Collar and Reducer-Brass
viiiStand (Frame)1Mild steel
IxDash Pad1Plastic
XD.C Motor1Aluminum
XiBattery1Lead-Acid
---------------------------------------------------------------------------------------
Chapter-12------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
COST ESTIMATION---------------------------------------------------------------------------------------
CHAPTER-12COST ESTIMATION
1. MATERIAL COST: Sl. No.PARTSQty.MaterialAmount (Rs)
i.Hydraulic Double Acting Cylinder2M.S
ii.3/2 solenoid Direction Control Valve2Aluminium
iii.Microcontroller Unit1Electronics
iv.Wheel4Rubber
v.Bearing with Bearing Cap4Fiber
vi.Polyethylene Tube-Polyurethene
vii.Hose Collar and Reducer-Brass
ViiiStand (Frame)1Mild steel
IxDash Pad1Plastic
XD.C Motor1Aluminum
XiBattery1Lead-Acid
TOTAL
=2. LABOUR COSTLATHE, DRILLING, WELDING, GRINDING, POWER HACKSAW, GAS CUTTING:
Cost = 3. OVERHEAD CHARGES
The overhead charges are arrived by Manufacturing cost
Manufacturing Cost=Material Cost + Labour cost
=
=
Overhead Charges=20% of the manufacturing cost
=
TOTAL COST
Total cost=Material Cost + Labour cost + Overhead Charges
=
=
Total cost for this project=
---------------------------------------------------------------------------------------
Chapter-13---------------------------------------------------------------------------------------
---------------------------------------------------------------------------------------
CONCLUSION---------------------------------------------------------------------------------------
CHAPTER-13CONCLUSION
This project work has provided us an excellent opportunity and experience, to use our limited knowledge. We gained a lot of practical knowledge regarding, planning, purchasing, assembling and machining while doing this project work. We feel that the project work is a good solution to bridge the gates between institution and industries.
We are proud that we have completed the work with the limited time successfully. The THREE AXIS HYDRAULIC MODERN TRAILER is working with satisfactory conditions. We are able to understand the difficulties in maintaining the tolerances and also quality. We have done to our ability and skill making maximum use of available facilities. In conclusion remarks of our project work, let us add a few more lines about our impression project work.
Thus we have developed a THREE AXIS HYDRAULIC MODERN TRAILER which helps to know how to achieve low cost automation. The operating procedure of this system is very simple, so any person can operate. By using more techniques, they can be modified and developed according to the applications.
---------------------------------------------------------------------------------------
BIBLIOGRAPHY---------------------------------------------------------------------------------------
BIBLIOGRAPHY
1. G.B.S. Narang, Automobile Engineering, Khanna Publishers, Delhi, 1991, pp 671.
2. William H. Crowse, Automobile Engineering.3. MECHANISMS IN MODERN ENGINEERING DESIGN Vol. V. PART I 4. ELEMENTS OF WORKSHOP TECHNOLOGY VOL II
-S.K. HAJRA CHOUDHURY
-S.K. BOSE
-A.K. HAJRA CHOUDHERY 5. STRENGTH OF MATERIALS
-I.B. PRASAD
Web site:
www.maritime.org
---------------------------------------------------------------------------------------
PHOTOGRAPHY---------------------------------------------------------------------------------------
DESIGN OF HYDRAULIC CYLINDER
Specification:-
Diameter
=40 mm
Stroke Length=100 mm
Shaft Dia
=12 mm
LOAD CALCULATION:
Cylinder bore
=16 Cms
= x (16/2)
=201.06193 cm
Max. Pressure=130 kg/cm
Load
=Area x pressure
=201.06193 x 130
=26138.051 kg
DESIGN OF CYLINDER WALL THICKNESS:
Internal diameter
=16 Cms
Max. Internal Pressure=130 kg/cm
Max. Hoop stress
=360 kg/cm
(Let the external radius be r Cms.
Let the radial pressure and Hoop stress at any radius x be given by,
Px=(b / x) a --------------------- (a)
And Fx=(b / x) + a
At x = 8 Cms
Fx=360 kg/cm
360=(b / 8) + a ------------------ (b)
Subtracting Equation (a) from Equation (b)
360 130=(b/64) + a (b/64) + a
230
=2a
a
=115
Substituting a to Equation (a)
130=(b/64) 115
b=245 x 64
b=15680
; Px = 0(We also know that x = r
0=(b (/ r) 9
(r=b / a
(r=15680 / 130 = 120.61538
(r=10.982504 Cms
Thickness of metal,
t=10.982504 8=2.982504
t=3 Cms (say)
DESIGN OF BALL BEARING
Bearing No. 6202
Outer Diameter of Bearing (D)
=35 mm
Thickness of Bearing (B)
=12 mm
Inner Diameter of the Bearing (d)
=15 mm
r
=
Corner radii on shaft and housing
r
=
1
(From design data book)
Maximum Speed
=
14,000 rpm(From design data book)
Mean Diameter (dm)
=
(D + d) / 2
=
(35 + 15) / 2
dm
=
25 mm
WAHL STRESS FACTOR
Ks
=
4C 1 + 0.65
4C 4 C
=
(4 X 2.3) -1 + 0.65
(4 X 2.3 )-4 2.3
Ks
=
1.85
DESIGN OF BALL BEARING
Bearing No. 6204
Outer Diameter of Bearing (D)
=47 mm
Thickness of Bearing (B)
=14 mm
Inner Diameter of the Bearing (d)
=20 mm
r
=
Corner radii on shaft and housing
r
=
1
(From design data book)
Maximum Speed
=
14,000 rpm(From design data book)
Mean Diameter (dm)
=
(D + d) / 2
=
(47 + 20) / 2
dm
=
33.5 mm
Spring index (C)
=
( D /d )
=
12 / 2
C
=
6
WALL STRESS FACTOR
Ks
=
4C 1 + 0.65
4C 4 C
=
(4 X 6) -1 + 0.65
(4 X 6 )-4 6
Ks
=
1.258
DESIGN OF D.C. MOTOR
Torque in a motor:
By the term torque, it is meant the turning or twisting moment of a force about an axis. It is measured by the product of the force and the radius at which this force acts.
For an armature of a motor, to rotate about its centre, a tangential force is necessary. This force is developed with in the motor itself.
Torque (T)
= ( Ia / A ) BDC Z Newton meters
Using the relation,
B
= / a
= / ( D / P )
= x P / ( D )
T= x (Ia / A) x Z x x {P/ (D) } x D
= Z P Ia / ( 2A ) Newton meters
=0.159 x x Z x Ia X (P/A) Newton meters
=0.162 x x Z x Ia x (P/A) Kg-m
The torque given by the above equation is the developed torque in the machine. But the output torque is less than the developed torque due to friction and windage losses.
#include
void lcd_init(void);
void read(unsigned char);
void write(unsigned char);
void lcd_dis(unsigned char *dis,unsigned char rr);
void delay(unsigned int);
void del();
void del1();
void ser_init();
void ser_out(unsigned char);
void ser_conout(unsigned char*dat,unsigned char );
void delay(unsigned int del);
sbit rs = P1^0;
sbit rw = P1^1;
sbit en = P1^2;
void del();
unsigned char x,acc,KK,ss,ss1;
sbit forward = P1^3;
sbit rev = P1^5;
sbit lft = P1^6;
sbit rit =P1^7;
sbit sen = P1^4;
sbit output1=P2^0;
sbit output2=P2^1;
sbit output3=P2^2;
sbit output4=P2^3;
sbit output5=P2^4;
void main(void)
{
ss=0;
ss1=0;
KK=0;
forward=1;
rev=1;
lft=1;
rit=1;
output1=0;
output2=0;
output3=0;
output4=0;
output5=0;
acc=0;
lcd_init();
read(0x01);
read(0x80);
lcd_dis(" FINGER BASED ",16);
read(0xc0);
lcd_dis(" WHEEL CHAIR ",16);
del();
output1=0;
output2=0;
output3=0;
output4=0;
output5=0;
while(1)
{
if(forward==0 && ss==0)
{
ss=1;
output1=1;
del();
output1=0;
}
if(sen==0 && ss==1)
{
ss=0;
output2=1;
del1();
output2=0;
}
if(sen==0 && ss1==1)
{
ss1=0;
output1=1;
del();
output1=0;
}
if(rev==0 && ss1==0)
{
ss1=1;
output2=1;
del1();
output2=0;
}
}
}
void del()
{
delay(60000);
delay(60000);
delay(50000);
}
void del1()
{
delay(60000);
delay(60000);
delay(60000);
}
void lcd_init()
{
read(0x38);
read(0x06);
read(0x0c);
}
void read(unsigned char y)
{
P0=y;
rs=rw=0;
en=1;
delay(225);
en=0;
}
void write(unsigned char y)
{
P0=y;
rs=en=1;
rw=0;
delay(225);
en=0;
}
void lcd_dis(unsigned char *dis,unsigned char rr)
{
unsigned char m;
for (m=0;m
