Friday, May 24

What Is Synchronous Motor


Introduction to what is synchronous motor

A synchronous motor (electric) is the another name of alternating current motor which converts the electrical energy into some mechanical energy. In the working of the  synchronous motor the rotor is spinning with the coils and then develops the magnetic field which is used to rotates the motor. Synchronous motor’s speed is determined by  pair numbers of the magnetic poles and the number of oscillations of the electric current (a.c) which is the alternating source of electricity.


Description of Synchronous Motor


The availability of the synchronous motors are in the sub fractional and self excited sizes to very high power and operating on the direct current also. The two types of the synchronous motors, which are used generally: one is non excited synchronous motor and the other is direct current excited synchronous motor. The non excited synchronous motors are constructed on the basis of the idea of reluctance and hysteresis designs, and they starts by the are self circuits and they do not require no any excitation supply of the energy. The reluctance design motors have 30 horse power efficiency. In the synchoronous motors there is a need of low torque and we can use these in the instrumentation applications. Synchronous motors are having the toothed rotors in some designs. The main parts of the synchronous motor are:

(i) the startor is the outer part as a shell of the motor which carries the armature windings, this winding is distributed for poly phase alternating current. The armature creates the rotating magnetic field.

(ii) the rotor is the moving part of the synchronous motor. The permanent magnet is produced by the field due to the windings.

(iii) the function of the slip rings in rotor is to supply the direct current to the windings of the wires in the direct current excited type synchronous motors.


Uses of synchronous Motor


Almost the synchronous motors of low horse power are used to provide the constant speed. The synchronous motors of high horse power are used for converting the energy  alternating current in the work which is useful for the different purposes in the heavy industries and the important use is that it work on power factor having value unity, that means the power loss is negligible.

Energy From The Sun Is Called


Introduction on energy from the sun is called:

The energy from sun is called Solar Energy. In fact, the best form of energy available to us is “SOLAR ENERGY”. The sun is the source of all energy. The sun provides us heat and light energy free of cost. The energy obtained from the sun is called solar energy. The nuclear fusion reactions taking place inside the sun keep on liberating enormous amounts of heat and light energy. This heat and light energy is radiated by the sun in all directions in the form of solar energy. The sun has been radiating an enormous amount of energy at the present rate for nearly 5 billions years and will continue radiating energy at that rate for nearly 5 billion years more. Since, the sin is very far away only a small fraction of the solar energy radiated by the sun reaches the outer layer of the earth’s atmosphere. A little less than half of the atmosphere actually reaches the surface of earth. The rest of solar energy is reflected back into space by the atmosphere and also absorbed by the atmosphere as it comes down through it towards the surface of the earth.


Advantages of solar energy


The best form of energy,solar energy which reaches the earth is absorbed by land and water-bodies as well as by plants. The solar energy trapped by land and water-bodies causes many phenomena in nature like winds, storms, rain, snowfall and sea-waves. The plants utilize solar energy to prepare food by the process of photosynthesis. The various sources of energy derive their energy from the sun, the best source of energy.

1. Non-renewable sources of energy, fossil fuels also derive their energy from sun. It is solar energy, which is converted into petroleum and oil.

2. Solar energy does not cause any pollution as compared to non-renewable sources of energy.

3. The solar energy is best form of energy because it is available in a diffused form so it is available to almost everyone on the earth.


Conclusion to solar energy


Finally ,the best source of energy, that is , solar energy is clean. It is a clean alternative to fossil fuels and nuclear power and it will never run out. It’s silent. Solar power can be captured anywhere without creating noise pollution that might otherwise up set neighbours and wildlife. It works wherever the sun shines. It doesn’t matter how remote, solar can generate energy where no other form of power can be obtained. Thus, no danger of damaging our already damaged environment further and you can be part of the Green initiative, lower your carbon footprint, and save our planet from harmful greenhouse gases.

Regular and Diffuse Reflection


Introduction to Regular and Diffused Reflection

When light traveling in one medium strikes a boundary leading to another medium, a part of incident light is through back into the original medium one. This phenomenon is called reflection of light.

Reflection is of two types:

Regular reflection
Irregular reflection or diffuse reflection


Description to regular and diffuse reflection


1.    Regular reflection: When the reflection surface is smooth and well polished, the parallel rays falling on it are reflected parallel to another one, the reflected light goes in one particular direction. This is regular reflection. The smooth and well polished surface is called mirror. Silver metal is one of the best reflectors of light. So, ordinary mirrors are made by depositing a thin layer of silver metal on one side of a plane glass sheet. The silver layer is protected by a coat of red paint. The reflection of light in a mirror takes place at the silver surface. A plane mirror is represented by a straight line, with a number of short, oblique lines showing back of the mirror.

2.    Diffuse reflection: When the reflecting surface is rough, the parallel rays falling on it are reflected in different direction. Such a reflection is known as diffuse reflection or irregular reflection or even scattering of light. In this, a surface will behave as a smooth surface as long as the surfaces variations are small as compared to the wavelength of incident light. As wavelength of visible light is very small therefore, every surface acts as a rough surface and scattering of light or irregular reflection is more common. For example, any object in a room can be seen from all the parts of the room. This is because surface of the object is rough and it scatters or reflects light in all directions.



Regular and Diffused Reflection : Summary


Reflection of light is the phenomenon of bouncing back of light in the same medium on striking the surface of any object.

Different Ways to Conserve Energy


Introduction to different ways of conserving energy:

When energy is saved, the demand for fossil fuels as oil, coal and natural gas is reduced. Less use of fossil fuels means less pollution, lower emissions of carbon dioxide and less global warming.Below is a house that uses various renewable energy and acts as an example for various ways to conserve energy.


Ways of conserving energy


Plant large, shady trees and paint a dark color to a house in a cold climate or a light color to a house in a warm climate. Trees absorb carbon dioxide from the air and give out oxygen.

Do not leave house hold appliances like Air Conditioner, computer, television, radio etc. on while you are out or when not needed.

Do not cool or warm areas that people are not in and close doors and windows in unused rooms.

Replace light bulbs with energy saving fluorescent bulbs.

Air dishes and clothes whenever possible.

Set lower temperature for the thermostat in the water heater, refrigerator and other heating or cooling devices to reduce electricity consumption. This cuts off the current supply sooner than; this is more efficient than using very hot water and then mixing it with cold water before for use.


Use solar water heaters.

Clean air filters regularly in the air conditioners. Free passage of air doesn't stress the device and thus reduce current.

Insulate doors, roofs and windows to reduce leakage of hot or cool air.

Use dishwasher and clothes washer at full capacity to as multiple usage increases electricity consumption.

Whenever possible get a walk, use mass transit or car pool than using your car daily. This reduces fuel consumption.

Use energy efficient appliances- with energy star label; though expensive, they use less current and reduce pollution and over a period of time save money.

Recycle and reuse whenever possible. Avoid packaged products and go for recyclable ones as they reduce pollution.

ways of conserving energy


Conclusion to different ways to conserve energy


From the discussion on conserving energy, we conclude that besides conserving energy, think of ways to use alternative sources of energy like, solar power, wind power, human powered mechanical energy etc.

Diffuse Reflection


Introduction to diffuse reflection:

The light rays travels in the straight line. The ray of light travels with the velocity of 3 × 108 metre per second. If the ray of light travels from one medium to another medium it suffers refraction due to the change in the velocity of light in different mediums. If the ray of light falls on the smooth and polished surface it suffers reflection. Here we discuss about reflection.I like to share this Fundamentals of Fluid Mechanics with you all through my article.


Diffused reflection:


The bouncing back of the light rays after striking from the highly polished and the smooth surfaces is called reflection. The image formed on retina so the we can see the objects is the very important example of reflection. As the rays of light falls on any object, the rays are reflected from the object and then enter in our eye. Now from the refraction of the eye lens the image of the object is formed on the retina. After that, the optical nerves carry the optical signals to the mind as the mind gives the permission to see the object we can see the image of the object very clearly. The reflection are of two types: one is called the specular or regular reflection and the other is diffused or irregular reflection. In the case of regular reflection, it obeys the laws of reflection completely but in case of the diffused reflection, it does not obey the laws of reflection completely. The diffused reflections are done by the non-polished or the slightly polished and non smooth or rough surfaces. As the rays of light falls on a rough and non-polished surface at any angle of incidence then the angle of reflection is not equal to the angle of incidence. Here the rays of light do not follow the first law of reflection. Similarly, the normal to the reflecting surface, incident ray and the reflected ray are not lie in the same plane, so the rays of light do not follow the second law of reflection.


Examples of the diffused reflection measurement:


The examples of the diffused reflection are the reading of newspaper or reading of a notebook. As we read the newspaper the images of the letters can be produce on the retina. Similarly, the ray of light from our body is reflected but the reflection is diffused so that we cannot see our image on the newspaper.

Thursday, May 23

Rotating Magnetic Field


Introduction to Rotating Magnetic Field:

A rotating magnetic field is a kind of magnetic field which ideally changes its direction at an angular rate which is constant. In the working of a motor that works on alternating current, the rotating magnetic field plays a key role as it is associated with its principle of operation. The concept of rotating magnetic field was introduced by Nikola Tesla in 1882. Galileo Ferrari's has done his research independently to introduce some more features of this concept in 1885.



Production of Rotating Magnetic Field


A rotating magnetic field which is symmetric can be produced using as few as three coils. To produce a rotating magnetic field, three coils should be driven by a symmetric three phase a.c. current and one of the phases is shifted to 120 degrees as compared to the other phase. In this case the magnetic filed should be taken as the linear function of the current which is flowing in the coil. The three phases which are 120 degrees out of phase compare to each other when applied to the axis of the alternating current motor then it produces a single rotating vector. This rotating vector follows the magnetic field in the coil and hence produces a rotating magnetic field .



Application of Rotating Magnetic Field


Rotating magnetic fields can also be used in the induction motors because the magnets, which are used, degrades with time and the induction motor use the short circuited rotor instead of a magnet, which is easily follow the rotating magnetic field produced by a stator, which is multi coiled. In the case of the induction motor, the turns of the rotor which is short circuited, develops the eddy current in the rotating magnetic field of the stator which is used to move the rotor by the developed Lorentz force. Such motors are generally not synchronous but they have involved a necessary degree of the slip by which the current will be produced due to the relative motion of the field and the rotor.

4 Simple Machines


Introduction to Simple Machines:

A simple machine is nothing but a kind of mechanical device which is used to change either the direction of the applied force or the magnitude of the given force. Generally the simple machines are defined in the simple way as the simplest mechanisms which are used to get the mechanical advantage, which is also called the leverage of the applied force in the specific and simpler manner. A simple machine uses the applied force for the work which is being done by the simple machine and the work is done against the single load force. If one ignores the losses that occur due to the friction then the work done by the applied force is equal to the work done on the given load. The simple machines can be used in order to increase the amount of the output force which is done at the cost of the decrease in the distance covered or moved by the load and this decrease is proportional to the increase in the output force.



Types of Simple Machines:


Usually there are six classical simple machines which are given below:

Lever

Wheel and axle

Pulley

Inclined plane

Wedge

Screw


4 Simple Machines


Pulley: The pulley is a simple machine used for the easy holding of the heavy weights. A pulley consists of the grooved wheels and the rope which is used to raise or lower or move any load.

Lever: A lever is nothing but a piece of the wood or the stiff bar of wood which is at rest on a support and the support is called the fulcrum and hence on that support it is used to lift or move the loads.

Wedge: A wedge is the object which has at least one side which is slanting and the same is ending in a sharp edge and this sharp edge is used to cut the materials apart.

Wheel & Axle: A wheel which is there with a rod which is called the axle and the compound system made the simple machine wheel and axle and in this simple machine the load is lifted or moved through the center of the machine.