Introduction
Electrical power can be generated through speed breaker by using special mechanical arrangement. The generated power can be stored in batteries for further use. The kinetic energy of a moving vehicle is converted into mechanical energy to run the generator and the mechanical arrangement occupies its previous state due to the restoring force in the spring. That means when the wheels of a moving vehicle press the speed breaker, the generator rotates in forward direction and after that when the wheels of the vehicle cross the speed breaker, the speed breaker moves upward due to the spring force. Here each vehicle contributes to a small amount of power production and this process goes on.
Components required
DC generator
Aluminium plate
Paper punching machine
Wood frame
Sun mica cover
Digital multimeter
1 watt LED
6 volt DC filament type bulb
Rechargeable battery.
Component description
DC generator
It is a shunt DC generator with permanent magnet field provided with metal gear and metal casing. If we use this generator in motoring mode supplying 12 volt DC its revolution per minute will be 30.
Aluminium plate
The thickness of the aluminium plate is approximately 1mm. Actually we have derived the plate from an aluminium frame which are generally used in making frames for doors and windows. It should be thick enough so that the crank should be strong without bending and squeezing. There should not be any deformation of the crank during operation.
Paper punching machine
We have used two paper punching machines as speed breakers. It is very useful due to its metal body and inbuilt spring. Its return mechanism is mostly suitable for our project.
Wood frame
The wood frame used in this project are available in a photo binding shop. Those are almost linear and ready to use. There cutting process is very easy with a mini hacksaw.
Sun mica cover
Sun mica cover comes in various sizes and are easily available in any electrical shop. We have used 11*13, 4*4 and 4*8 three sun mica covers.
Digital multimeter
A digital multimeter is one of the most widely used pieces of measuring instrument now a days. It is used by every professional electrical and electronics engineers. it has several applications in all electrical and electronics laboratory. Its operation is very easy and simple. Here we have used it to measure the DC voltage produced by the generator.
1 watt LED
We have used a 1 Watt Light Emitting Diode of white type to test the output of generator. It has two terminals one is positive terminal and other is negative terminal. These terminals are joined with crocodile clips followed by supporting wires to be connected with generator terminals directly. Voltage range applied between anode and cathode is 3.0 V to 3.5 V. The typical operating voltage is generally 3.3 V. It can conduct a maximum current of 350mA through it.
6 volt DC filament type bulb
Although it is a very traditional bulb and consuming a comparatively higher current as compared to LED, I have always found it fascinating, glowing a such type of bulb by rotating a generator. The filament’s increasing and decreasing strength of light in a rhythm of generators speed is really interesting.
Rechargeable battery
We have used here a 4 volt and 1.5Ah rechargeable lead acid battery. These are easily available in markets and suitable for project works.
Law of conservation of energy
In physics the law of conservation of energy states that the total energy of an isolated system remains constant. That means energy can neither be created nor destroyed. It can only be transformed or transferred from one form to another.
Here the law of conservation of energy is followed. We are just transforming the kinetic energy of a vehicle into electrical energy. Otherwise the kinetic energy will be wasted as friction and heat. Here in this particular arrangement for every single press of the speed breaker we are generating approximately 7V dc. This is sufficient to charge a 4 volt lead acid battery if the process continues.
This mechanical arrangement is similar to first type of lever action. The effort and the load are in either side of the fulcrum. The special spring arrangement always engages the metal hook with the crank fitted to the generator shaft.
The crank and the hook arrangement rotates the generator in forward direction only. The mechanical arrangement is somehow similar to pawl and ratchet mechanism. The ratchet is the toothed wheel fitted to the generator shaft. The aluminium hook acts like pawl.
The inertia of moving armature of generator is sufficient to drive the generator in only one direction. Due to the presence of pawl, ratchet can’t rotate in other direction. The entire mechanism is fitted underground.
Pawl and ratchet mechanism
A ratchet mechanism is based on a gear wheel and a pawl is always engaged to follow the rotating wheel. The pawl is then jammed against the depression between the gear teeth, preventing any backward rotation. Ratchet mechanisms are very useful devices for allowing linear or rotary motion in only one direction. These applications are found in wrist watch, bicycle wheel, lifting jack while repairing a punctured tyre and in many machineries. The main purpose of a ratchet and pawl is to allow a shaft to rotate in one direction only just like in our project. A ratchet fits onto a shaft and is locked onto the shaft by a “key”. The key fits into slots in the shaft and ratchet wheel. These slots are called “keyways”. A pawl is a metal part that rests on the ratchet. Pawl may be itself a spring type material or a metal hook like structure provided with spring. In a pawl and ratchet mechanism generally the ratchet rotates and the pawl is assigned to rotate the ratchet in a single direction. But in this particular case the pawl is pulling the ratchet and tries to rotate it as well as blocking it to rotate it in opposite direction. This arrangement is intentionally set here because a generator can rotate in both the directions and in this way polarity can be changed but we have to continuously charge the battery with one time connection.
For more facts watch the video in our YOU TUBE channel.
