In initial stages DC used to be employed for Generation, Transmission and distribution of electric power. First DC 110 Volt Central Electric Station was installed by Edison in New York in the year 1882. After Introduction of Transformer and single phase, Three Phase AC system the situation changed, in favor of AC.
For many reason such as facility of transformation of voltage from one to another, better performance AC power become popular and starts to use widely in all cases transmission, generation, distribution.
Benjamin Franklin performed a famous experiment of FLYING KITE in thunder cloud in the year 1745. Before his discovery the lightning used to be considered to be “ACT OF GOD”. He also proved that the lightning stroke is because of the discharge of electricity. He also invented protection of lightning. Lightning rods for fixation on tall buildings and grounding for their protection from lightning stroke. Thus Benjamin Franklin is a great scientist in this field.
WHAT IS LIGHTNING?
Lighting is a huge spark which is due to electrical discharge taking place between the clouds within the same cloud or between the cloud and earth or ground. Large number of discharge occur between or within clouds than earth. And enough of them terminate on to the earth and result in serious hazards. This discharge occurs between electrically charged regions of a cloud (called intra-cloud lightning or IC), between two clouds (CC lightning), or between a cloud and the ground (CG lightning). Continue reading “MECHANISM OF LIGHTNING”
Power Transformer are used for stepping-up the voltage for transmission at generating stations and for stepping-down for further distribution at substation. Usually naturally cooled, oil immersed, On type, two winding. three phase transformer are used up to the rating of 10 MVA. The transformers of rating higher than 10 MVA are usally Air-blast cooled. For very high rating transformer the forced oil, water cooling or air blast cooling may used.
For regulating the voltage the transformers used are provided with on load tap changer. They are put in operation during load hours and disconnect during light load hour, that is they are usually operated at approximately full load condition. This is possible because they are arranged in bank and parallel with other unit or disconnected at will.
Design: Power Transformer
So power transformer are designed to have maximum efficiency at or near full load condition. that is iron loss to full load copper loss ration is 1:1.
Power Transformer are designed to have consider leakage reactance than permissible in distribution transformers because in power transformers inherent voltage regulation is not as much important as current limiting effect of the higher leakage reactance.
Power Transformer usually make use of flux density of 1.5 to 1.77, have percentage impedance ranging from 6-18% and regulation 6-10%.
SPECIFICATION OF TRANSFORMER :
Number of phase (single phase or three phase)
Type of Core ( shell type or core type )
Tapping – if any
Frequency (in INDIA 50hz, USA- 60hz)
Construction ( Delta type or Star Type in case of three phase)
Type of cooling ( air cooling, oil cooling)
Ambient Temperature ( Average 40° C)
No-load Current in ampere or percentage of rated current at at rated voltage and rated frequency.
Efficiency in percent at full load, half load, 3/4 load at unity or 0.8 pf (power factor).
Power Transformer are generally installed upon lengths of rail fixed on concrete slab having foundation 1 to 1½ meter deep.
With the help of some software you can easily do that but without any software you can do it very easily. you can do it in any windows operating system ( i.e.- windows 7, 8, 10, xp, vista)
just follow those step and you can do it yourself…
firstly open your command prompt on administrator mode- for that search command prompt and right click on it and choose RUN AS ADMINISTRATOR or you can go to start>>all programs>>accessories >> command prompt then right click on it and choose run as administrator.
after that type a command – netsh wlan set hostednetwork mode=allow ssid=”your network name” key=”password” hit enter [this step for just one time]
then type a another command to start hosted network- netsh wlan start hosted hit enter
then go to network sharing center- go to control panel>> choose network & sharing center
then choose connection you want to share (click on connected network)
then a box open- click on properties >> click on sharing tab and click on allow check box, a dialog box open click on OK. then below home network connection a selection presents click on it and choose the network you want to share ( connected network)
click on setting tab – advance setting open and check all the boxes ( ftp server, remote desktop, internet mail sever, and many other). if you check one box a dialog open click OK each time.
We know that when an electric current flowing though a conductor a magnetic
field is brought into existence in the space surrounding the conductor. it can
say that when electrons are in motion they produce magnetic field. when a magnetic field embracing a conductor moves relative to the conductor it produces a flow electrons in the conductor. This phenomenon whereby an e.m.f and current is induced in any conductor which cut across or cut by a magnetic flux is known as ELECTROMAGNETIC INDUCTION.
HISTORY OF MAGNETIC INDUCTION:
After discovery of that electric current produces magnetic field, scientist are trying to search for the converse phenomenon from about 1821. The problem they put themselves was – how to convert Magnetism to Electricity. It is recorded that Michael Faraday ( A English Physicist and Chemist) was in the habit of walking about with magnets in his pocket so as constantly remind him of the problem to solve.
After Nine year of continuous full phase research and experiment he succeeded in the producing electricity by converting magnetism. In 1831 he formulated basic laws underlying the phenomenon of electromagnetic induction, after that these know by Faraday’s Law. Motor, Generator, Transformer, Induction cooker and many other apparatus based on this law.
At first Bruner (1967) states that “The threshold of perception of electric shock is about 1 mA.” At this level a tingling sensation is felt by the subject when there is a contact with an electrified object through skin. If the magnitude of electric increase the sensation of tingling gives way to contraction of muscles. The muscular contraction increase as current is increase. Finally a value current is reached at a point that the subject cannot release his grip on the current carrying conductor.
The maximum current at which the subject is still capable of releasing a conductor by using muscles directly simulated by the current is called LET GO CURRENT.
In dc circuit when large current are to be measured its normally use low range ammeter with suitable (low resistance) shunt connected in parallel. when large voltage are to be measured use low range voltmeter with high resistance connected in series. But this method is not convenient for practical use for AC voltage and current instruments.
For this purpose specially constructed with high accuracy Instrument Transformer or Measurement Transformer are used. Their purpose is to reduce line current or voltage to a value small to be easily measured with meters of moderate capacity.
Electric battery consists of a number of electro-chemical cells, which may connected in either parallel or series. electrical battery is a source of DC voltage,
DEFINATION OF CELL:
a cell is a basic unit of a battery. it is defined as power generating device, which can converts storage chemical energy into electrical energy.
PRIMARY BATTERY: NON RECHAREABLE
If the stored chemical energy is constitutionally or inherently present in the chemical substances, its called primary cell or non-rechargeable cell. if the battery made up with these kinds of cells the battery is call PRIMARY BATTERY.