Projects (Electrical)

Autocut Stabilizer 

Introduction:

There are huge varieties of voltage stabilizers available in the market, and surely it's not a big deal to procure one, according to the needs. But off course it can be very amusing to build one at home all by you and see it actually working. The circuit of an Automatic Voltage Stabilizer (AVS) described in this article is in fact very simple in design, reasonably precise and will give a good protection to the electronic gadget that is connected to it. It will particularly guard them against the dangerous high voltages and also from the possible brownouts (low voltages).The output will stay in the range of 200VAC – 255VAC with an input voltage of 175VAC – 280VAC.

How does a Voltage Stabilizer Work?

In one of my previous articles you must have learnt regarding the functioning of an auto transformer. There we have studied how an auto transformer may be used to produce voltages higher and lower than the input supply mains AC voltage. An auto transformer in fact plays the most important part in a voltage stabilizer circuit.

The circuit of a voltage stabilizer basically consists of a voltage sensor. It is configured to detect the rise or fall of the AC mains voltage to dangerous levels. As soon it senses a risky input voltage, it immediately energizes the relays connected to it. These relays in turn swaps and switches the appropriate winding terminals of the auto transformer to correct and stabilize the output voltage. Thus the appliance which is connected to the output of the voltage stabilizer circuit always receives a safe, tolerable voltage and is able to function reliably, irrespective of the fluctuating input voltages.

Let’s proceed to know what are the parts required to build it and also its construction details.

Parts Required

You will require the following parts for the circuit:

Resistor ¼ watt, CFR R1 = 2 K 7,

Preset P1 = 10 K Linear,

Transistor T1 = BC 547,

Zener diode Z1 = 3 V / 400 mW,

Diode D1, D2 = 1N4007,

Capacitor = 220uF / 25 V

Relay RL1 = 12 V / DPDT mini (double pole, double throw),

Transformer T1 = 12 – 0 – 12 V / 5 amps. T2 = 0 – 12 volts / 500 mA (input as per country specifications)

General purpose board = 3" by 3"

Construction Clues

With the help of the given circuit schematic (on the next page) the construction of this simple AVS circuit may be completed through the following easy steps:

In the given piece of general purpose board, insert the transistor, solder and cut its leads.

Proceed by fixing and soldering the rest of the associated parts along with the relay around the transistor.

Interlink all of them as per the circuit schematic.

Finally connect the primary and the secondary wires of the transformer to the relay contacts as shown in the diagram.

The next page covers the circuit and the construction details of this automatic voltage stabilizer circuit.

A simple voltage stabilizer circuit to protect your home appliances can be built by using just a handful of electronic components and a couple of transformers. It will keep the output within 200 and 250 or 100 and 125 against input extreme variations between 180 and 260 or 90 and 130 volts respectively as per country specifications.

Circuit Description

The functioning of this simple voltage stabilizer circuit may be understood from the following points:

Referring to the figure (Click to Enlarge) we see that Transistor T1 forms the main active part of the entire circuit.

The voltage from smaller transformer is rectified by D1 and filtered by C1 to produce the required operating power for the control circuit comprising of transistor T1, preset P1, zener diode Z1 and the DPDT relay.

The above voltage is also used as the basic reference or the sensing voltage. Because this voltage will vary proportionately with the applied input voltage variations.

For example, if normally the operating DC voltage is around 12 volts, an increase or decrease of the input AC mains voltage by say 25 volts would proportionately increase or decrease the DC volts to 14 or 10 volts respectively.

Preset P1 is set such that the transistor conducts and operates the relay whenever the input AC mains tends to deviate above the exact normal voltage (110 or 225 volts) and vice versa.

If the input voltage crosses the above limit, T1 conducts and activates the relay. The relay contacts connect the relevant connections of the power stabilizer transformer to deduct 25 volts from the input i.e. bring the output to about 205 volts. From here on if the mains voltage keeps on increasing, the ouput to the appliances will be 25 volts below it. It means, even if the voltage reaches as high as 260 V, the output will reach only up to260 - 25 = 235 volts.

Exactly opposite will happen in case the input AC drops below the normal level, i.e. in this case 25 volts will be added to the output, and even if the input keeps on dropping and reaches 180 volts, the output will reach only up to 180 + 25 = 205 volts.

The present design is very simple and basic, therefore the stabilization cannot be very precise. But certainly it will keep the output within 200 and 250 volts against input extreme voltages of 180 to 275 volts (or within 100 and 125 against 90 and 130 volts).

How to Test it?

The completed circuit board of simple voltage stabilizer may be tested in the following method:

For the testing procedure you will require a 0 – 12 volts universal DC variable power supply.

You can assume the maximum 12 volts of the power supply to be equivalent to an input of approximately 230 VAC. We will take this voltage as the trip or the change-over voltage of the stabilizer.

Connect the power supply to the supply terminals of the completed circuit board.

Keep the voltage of the power supply to its maximum position of 12 volts.

Carefully adjust the preset so that the relay just gets activated.

Now on decreasing the power supply voltage by 1 volt i.e. to 11 volts should restore the relay back to its deactivated position.

REFERENCES:

1- DIPAK KUMAR RAI

2- ALOK KUMAR RAI

3- HARSHITA SRIVASTAV

4- JAYA CHAUDHARY

5- PINKY VERMA

6- HIRA LAL BIND

(all students are from Town polytechnic Ballia)

Under Project-

Er S K SINHA

HOD-Er S K SRIVASTAV

Lect Er J P PANDEY

(From TOWN POLYTECHNIC BALLIA)

Projects (Mechanical)

DESIGN AND FABRICATION OF MOTORIZED SCREW JACK FOR A FOUR WHEELER A PROJECT REPORT Submitted in partial fulfillment for the award of the degree of BACHELOR OF TECHNOLOGY IN MECHANICAL ENGINEERING By Vikas Kumar Rai

Abstract:

With the increasing levels of technology, the efforts being put to produce any kind of work has  been continuously decreasing. The efforts required in achieving the desired output can be effectively and economically be decreased by the implementation of better designs. Power screws are used to convert rotary motion into translatory motion. A screw jack is an example of a power screw in which a small force applied in a horizontal plane is used to raise or lower a large load. The principle on which it works is similar to that of an inclined plane. The mechanical advantage of a screw jack is the ratio of the load applied to the effort applied. The screw jack is operated by turning a lead screw. The height of the jack is adjusted by turning a lead screw and this adjustment can be done either manually or by integrating an electric motor. In this project, an electric motor will be integrated with the screw jack and the electricity needed for the operation will be taken from the battery of the vehicle and thereby the mechanical advantage will be increased.

Power Screw:

A power screw is a mechanical device used for converting rotary motion into linear motion and transmitting power. A power screw is also called translation screw. It uses helical translatory motion of the screw thread in transmitting power rather than clamping the machine components.

2.1 Applications

The main applications of power screws are as follows:

(i) To raise the load, e.g. screw-jack, (ii) To obtain accurate motion in machining operations, e.g. lead-screw of lathe, (iii) To clamp a workpiece, e.g. vice, and (iv) To load a specimen, e.g. universal testing machine. There are three essential parts of a power screw, viz.screw, nut and a part to hold either the screw or the nut in its place. Depending upon the holding arrangement, power screws operate in two different ways. In some cases, the screw rotates in its bearing, while the nut has axial motion. The lead screw of the lathe is an example of this category. In other applications, the nut is kept stationary and the screw moves in axial direction. Screw-jack and machine vice are the examples of this category.

2.2 Advantages

Power screws offer the following advantages: (i) Power screw has large load carrying capacity. (ii) The overall dimensions of the power screw are small, resulting in compact construction. (iii) Power screw is simple to design (iv) The manufacturing of power screw is easy without requiring specialized machinery. Square threads are turned on lathe. Trapezoidal threads are manufactured on thread milling machine. (v) Power screw provides large mechanical advantage. A load of 15 kN can be raised by applying an effort as small as 400 N.Therefore, most of the power screws used in various applications like screw-jacks, clamps, valves and vices are usually manually operated. (vi) Power screws provide precisely controlled and highly accurate linear motion required in machine tool applications. (vii) Power screws give smooth and noiseless service without any maintenance. (viii) There are only a few parts in power screw. This reduces cost and increases reliability.

Screw jack:

A screw jack is a portable device consisting of a screw mechanism used to raise or lower the 

load. The principle on which the screw jack works is similar to that of an inclined plane. There

are mainly two types of jacks-hydraulic and mechanical. A hydraulic jack consists of a cylinder 

and piston mechanism. The movement of the piston rod is used to raise or lower the load. 

Mechanical jacks can be either hand operated or power driven.

Jacks are used frequently in raising cars so that a tire can be changed. A screw jack is commonly 

used with cars but is also used in many other ways, including industrial machinery and even 

airplanes. They can be short, tall, fat, or thin depending on the amount of pressure they will be

under and the space that they need to fit into. The jack is made out of various types of metal, but 

the screw itself is generally made out of lead.

While screw jacks are designed purposely for raising and lowering loads, they are not ideal for 

side loads, although some can withstand side loads depending on the diameter and size of the 

lifting screw. Shock loads should also be avoided or minimized. Some screw jacks are built with 

anti-backlash. The anti-backlash device moderates the axial backlash in the lifting screw and nut 

assembly to a regulated minimum.

A large amount of heat is generated in the screw jack and long lifts can cause serious 

overheating. To retain the efficiency of the screw jack, it must be used under ambient 

temperatures, otherwise lubricants must be applied. There are oil lubricants intended to enhance 

the equipment‟s capabilities. Apart from proper maintenance, to optimize the capability and 

usefulness of a screw jack it is imperative to employ it according to its design and 

manufacturer‟s instruction. Ensure that you follow the speed, load capacity, temperature 

recommendation and other relevant factors for application

3.1 The Screw

The screw has a thread designed to withstand an enormous amount of pressure. This is due to the 

fact that it is generally holding up heavy objects for an extended amount of time. Once up, they 

normally self lock so that they won't fall if the operator lets go, and they hold up well to the wear 

of repeated use. If they are made with a ball nut, they will last longer because there is less 

friction created with this type of jack. However, they will not self lock. This can be dangerous 

and handled carefully.

3.2 Operation

The jack can be raised and lowered with a metal bar that is inserted into the jack. The operator 

turns the bar with his hands in a clockwise direction. This turns the screw inside the jack and 

makes it go up. The screw lifts the small metal cylinder and platform that are above it. As the 

jack goes up, whatever is placed above it will raise as well, once the jack makes contact. The bar 

is turned until the jack is raised to the level needed. To lower the jack the bar is turned in opposite direction. An automatic screw jack has gears inside the jack that are connected to the 

screw. Theses gears are connected by other gears and bars that are turned by a power source to 

raise and lower the jack.

Although a jack is a simple and widely used device, the use of any lifting device is subject to 

certain hazards. In screw-jack applications, the hazards are dropping, tipping or slipping of 

machines or their parts during the operation. These hazards may result in serious accidents. The

main reasons of such accidents are as follows:

(i) The load is improperly secured on the jack

(ii) The screw-jack is over loaded.

(iii) The centre of gravity of the load is off centre with respect to the axis of the jack

(iv) The screw-jack is not placed on hard and level surface.

(v) The screw-jack is used for a purpose, for which it is not designed.

Proper size, strength and stability are the essential requirements for the design of the screw-jack 

from safety considerations.

3.3 Construction of Screw Jack

Screw jack consists of a screw and a nut. The nut is fixed in a cast iron frame and remains 

stationary. The rotation of the nut inside the frame is prevented by pressing a set screw against it. 

The screw is rotated in the nut by means of a handle, which passes through a hole in the head of 

the screw. The head carries a platform, which supports the load and remains stationary while the 

screw is being rotated. A washer is fixed to the other end of the screw inside the frame, which 

prevents the screw to be completely turned out of the nut.

3.4 Function

The basic function of a screw jack is to lift a portion of a vehicle. Typically this is used to change 

a tire although other maintenance is sometimes performed.

3.5 Features

All jacks have safety features to protect the user from accidental injury. Wide bases help to 

stabilize a jack and prevent tilting or sinking into soft soil. Most car jacks also come equipped 

with their own handle or cranking mechanism, but alternately many of these also will accept the 

flat end of a tire tool to jack up a vehicle. When in the extended position, jacks will have a stop 

point that prevents the user from overextending the jack beyond its rated capabilities. When in 

the contracted position, jacks that are provided by the manufacturer will have a storage area 

specially formed or designed for the jack to rest in when not in use.

Construction:

A scissor jack has four main pieces of metal and two base ends. The four metal pieces are all 

connected at the corners with a bolt that allows the corners to swivel. A screw thread runs across 

this assembly and through the corners. As the screw thread is turned, the jack arms travel across 

it and collapse or come together, forming a straight line when closed. Then, moving back the 

other way, they raise and come together. When opened, the four metal arms contract together, 

coming together at the middle, raising the jack. When closed, the arms spread back apart and the 

jack closes or flattens out again.

Design and Lift:

A scissor jack uses a simple theory of gears to get its power. As the screw section is turned, two 

ends of the jack move closer together. Because the gears of the screw are pushing up the arms, 

the amount of force being applied is multiplied. It takes a very small amount of force to turn the 

crank handle, yet that action causes the brace arms to slide across and together. As this happens 

the arms extend upward. The car's gravitational weight is not enough to prevent the jack from 

opening or to stop the screw from turning, since it is not applying force directly to it. If you were 

to put pressure directly on the crank, or lean your weight against the crank, the person would not 

be able to turn it, even though your weight is a small percentage of the cars.

Introduction:

The motorized screw jack has been developed to cater to the needs of small and medium 

automobile garages, which are normally man powered with minimum skilled labor. In most of 

the garages the vehicles are lifted by using screw jack. This needs high man power and skilled 

labour.

In order to avoid all such disadvantages, the motorized jack has been designed in such a way that 

it can be used to lift the vehicle very smoothly without any impact force. The operation is made 

simple so that even unskilled labour can use it with ease.

The d.c motor is coupled with the screw jack by gear arrangement. The screw jack shaft‟s 

rotation depends upon the rotation of D.C motor. This is a simple type of automation project.

This is an era of automation where it is broadly defined as replacement of manual effort by 

mechanical power in all degrees of automation. The operation remains to be an essential part of 

the system although with changing demands on physical input, the degree of mechanization is 

increased.

Need for Automation:

Automation can be achieved through computers, hydraulics, pneumatics, robotics, etc. 

Automation plays an important role in mass production.

For mass production of the product, the machining operations decide the sequence of 

machining. The machines designed for producing a particular product are called transfer 

machines. The components must be moved automatically from the bins to various machines 

sequentially and the final component can be placed separately for packaging. Materials can also 

be repeatedly transferred from the moving conveyors to the work place and vice versa.

Nowadays, almost all the manufacturing processes are being atomized in order to deliver the 

products at a faster rate. The manufacturing operation is being atomized for the following 

reasons:

 To achieve mass production

 To reduce man power

 To increase the efficiency of the plant

 To reduce the work load

 To reduce the production cost

 To reduce the production time 

 To reduce the material handling

 To reduce the fatigue of workers

 To achieve good product quality

 Less Maintenance

CONCLUSION:

Screw Jacks are the ideal product to push, pull, lift, lower and position loads of anything from a 

couple of kilograms to hundreds of tonnes.The need has long existed for an improved portable 

jack for automotive vehicles. It is highly desirable that a jack become available that can be 

operated alternatively from inside the vehicle or from a location of safety off the road on which 

the vehicle is located. Such a jack should desirably be light enough and be compact enough so 

that it can be stored in an automobile trunk, can be lifted up and carried by most adults to its 

position of use, and yet be capable of lifting a wheel of a 4,000-5,000 pound vehicle off the 

ground. Further, it should be stable and easily controllable by a switch so that jacking can be 

done from a position of safety. It should be easily movable either to a position underneath the 

axle of the vehicle or some other reinforced support surface designed to be engaged by a jack.

Thus, the product has been developed considering all the above requirements. This particular 

design of the motorized screw jack will prove to be beneficial in lifting and lowering of loads.

To download this project  click here.download this file in pdf

Infrastructure of Engineering

Skill:

There are many qualities
and skills an individual
needs to become an
effective engineer and to
have a successful career.
Engineering is dynamic so
it needs people who can
work across disciplines,
with others, and continually
adapt to new challenges.
Good technical skills are of
course also essential. In
preparation for an
engineering career you
should focus on developing
a variety of skills,
including

Technical Competence: 

The
focus is on having the
necessary technical skills
and ability to carry out your
job. While an engineering
education will provide the
foundation of this
knowledge, as technology is
constantly advancing you
will be expected continue to
learn throughout your
career.

Communications Skills: 

To

be in effective engineer you
must have the ability to
communicate, both in
writing and orally. Focus
on your writing skills,
consider developing a
competency in a second
language and also develop
your public speaking skills.
A good communicator has
influence and most
importantly, gets noticed.

Leadership Skills:

Leadership is more than
just the position you’re in,
it’s about action. An
example where you will
need leadership skills is
during project management
where you will need to plan,
set priorities, delegate,
make decisions and to
influence people. To help
you develop these skills get
involved in a civic, school,
professional or church
group as a volunteer.

Teamwork: 

To be an
effective engineer you will
need the ability to work in a
team environment.
Volunteer activities will
also allow you to gain
experience of team
working. Problem solving:
As an engineer your job will
be to come up with the
answers and to do that you
need the ability to think, to
look at the issues and
come up with a solution.
Good engineers are
therefore to be able to think
critically, analyze options
and to create great
solutions to problems that
they have not encountered
before.

Summary:

 To be an
effective engineer you don’t
need to master each of
these qualities and skills.
The successful engineer is
well-rounded, with
knowledge of the key skills
and an ability to apply
them when needed. It will
take effort on your part, but
the fun is in the learning
and the reward is
accomplishing your tasks
and seeing the impact your
work will have on society.

Contact Us

VIKAS KUMAR RAI
Email- vkr0253@gmail.com

ABOUT US

It is a non profit organizationand registered society for propagating the profession of industrial engineering in world .it was founded in 2016 .
A member can join seminars ,workshops,training,programs,industry visits, and other professional activities of institution.
This group brings out a monthly journal entitled "Industrial engineering journal". It publishes papers and articles relating to application as industrial engineering and management technique, including research work.

 Mr. VIKAS KUMAR RAI 

(A.M.I.E. FROM West Bengal &Diploma in Mechanical engineering Production from Govt Polytechnic Moradabad)

 More detail