EAEP-Electrical and Electronics Portal

Star-Delta starter Introduction: According to electromagnetic induction principle, once a supply is connected to a three phase induction motor a rotating magnetic field will be set up in the stator, this will link and cut the rotor bars which in turn will induce rotor currents and create a rotor field which will interact with the stator field and starts rotating. Of course this means that the three phase induction motor is entirely capable of self-starting. Need of starter: The need for a starter therefore is not, but in case of three phase induction motor starter is to provide smooth starting, to reduce Heavy starting currents, provide overload and no-voltage protection.

Scheme: Fluorescent lamp What is Fluorescent lamp? A fluorescent lamp , or fluorescent tube , is a low-pressure mercury-vapor gas-discharge lamp that uses fluorescence to produce visible light. An electric current in the gas excites mercury vapor, which produces short-wave ultraviolet light that then causes a phosphor coating on the inside of the lamp to glow. A fluorescent lamp converts electrical energy into useful light much more efficiently than incandescent lamps. The typical luminous efficacy of fluorescent lighting systems is 50–100 lumens per watt, several times the efficacy of incandescent bulbs with comparable light output.                                (by Wikipedia)

Tariff and Economic Considerations Economic Motive:  In all engineering projects with the exception of the construction of works of art or memorial buildings, the question of cost is of first importance. In fact, in most cases the cost decides whether a project will be undertaken or not although political and other considerations may intervene sometimes. However, the design and construction of an electric power system is undertaken for the purpose of producing electric power to be sold at a profit. Hence, every effort is made to produce the power as cheaply as possible. The problem of calculating the cost of any scheme is often difficult because the cost varies considerably with time, tariffs and even with convention. In general, the cost of producing electric power can be roughly divided into the following two portions:

  History of paper a brief: Paper was first discovered in ancient China, and the first material used for writing was a "tree" called papyrus. These papyrus materials are not defined as real paper. It was first documented in China during the Eastern Han period (25-220 CE), usually told to a court official. Spread to the Islamic world during the 8th century. The algorithm of the 11th century was brought to medieval Europe. Later in the 19th century came the Western developments in the field of paper with the invention of wood-based papers.

As for the electrician's kit, the most essential thing for every electrician is that they cannot do without the kit, and the kit is essential to complete the biggest tasks easily and on time. Electrical work cannot be done without the right tools, and some basic tools are essential for every electrician to do their job safely and efficiently. So, we have prepared a short list that they are ‘very essential tools’ that every electrician should have in their tool box. 1. Combination Plier Combination plier source_Taparia It is made of steel and its size is given according to its length. It has a cutter for cutting the wires. It is so named because it is used for multi-purpose, such as cutting, twisting of wire sand holding round and flat jobs. They are either insulated or non-insulated. An insulated combination plier is specially used to work on live conductors where it prevents the current from leaking to the human body.

  Definition of a Logic Gate: "A logic gate is an electronic circuit which makes logic decisions". It has one output and one or more inputs. The output signal appears only for certain combinations of input signals. Logic gates are the basic building blocks from which most of the digital systems are built up. They implement the hardware logic function based on the logical algebra developed by George Boole which is called Boolean algebra in his honour. A unique characteristic of the Boolean algebra is that variables used in it can assume only one of the two values i.e. either 0 or 1. Hence, every variable is either a 0 or a 1.

  What Is a Level Controller? A Conductive Level Controller electrically detects the level of a liquid. Conductive Level Controllers are electronic liquid level detectors used in a wide range of applications such as water and sewer services for office and apartment buildings, industrial applications for iron and steel, food, chemical, pharmaceutical, and semiconductor industries, and liquid level control for agricultural water, water treatment plants, and wastewater plants. When the electrodes are in contact with liquid, the circuit is closed (the liquid completes the path for electricity to flow) and the electrical current that flows in this circuit is used to detect the level of the liquid. A variety of conductive liquids can be controlled using this method. Detecting the resistance between the electrodes and comparing it to see if it is larger or smaller than a reference resistance is used to detect the surface of the liquid.

1.Ohm´s law: The ratio of potential difference (V) between any two points on a conductor to the current (I)  flowing between them, is constant, provided the temperature of the conductor does not change.                               In other words, V/I= constant or V/I= R 2.Kirchhoff´s law´s:  a. Kirchhoff’s Point Law or Current Law (KCL) In any electrical network, the algebraic sum of the currents meeting at a point (or junction) is zero.                               i.e incoming currents = outgoing currents  b. Kirchhoff’s Mesh Law or Voltage Law (KVL) The algebraic sum of the products of currents and resistances in each of the conductors in  any closed path (or mesh) in a network plus the algebraic sum of the e.m.fs. in that path is zero.