Basic Electrical Engineering

Switchgear: The apparatus used for switching, controlling and protecting the electrical circuits and equipment is known as switchgear. Classification of Switchgear: Switchgear can be classified on the basis of voltage level into the following:  1. Low voltage (LV) Switchgear: up to 1 KV   2. Medium voltage (MV) Switchgear:  3 KV to 33 KV   3. High voltage (HV) Switchgear: Above 33 KV . Components of LT Switchgear: The term LT Switchgear includes low voltage Circuit Breakers, Switches, off load electrical isolators, HRC fuses, Earth Leakage Circuit Breaker, Miniature Circuit Breakers (MCB) and Molded Case Circuit Breakers (MCCB) etc i.e. all the accessories required to protect the LV system. The most common use of LV switchgear is in LV distribution board. FUSE: Fuse is the simplest and cheapest device used for interrupting an electrical circuit under short circuit, or excessive overload, current magnitudes. The action of a fuse is based upon the heating...

Earthing is defined as “the process in which the instantaneous discharge of the electrical energy takes place by transferring charges directly to the earth through low resistance wire.” Low resistance earthing wire is chosen to provide the least resistance path for leakage of fault current. In simple words  The process of sharing the charges with the earth is called earthing.  Mostly, the galvanized iron is used for the earthing. The  earthing provides the simple path to the leakage current . The short-circuit current of the equipment passes to the earth which has zero potential. Thus, protects the system and equipment from damage. In homes, there shall be three types of wires, live, neutral, and earth. Live and  neutral   carry electric current from the power station and the earth is connected to the buried metal plate. Electric appliances like refrigerators, iron boxes, and TV are connected to the earth wire while operating. Hence, these devices are ...

It is  the process of compensating for the lagging current by creating a leading current by connecting capacitors to the supply . A sufficient capacitance is connected so that the power factor is adjusted to be as close  as possible  to unity . When dealing with direct current (DC) circuits, the power dissipated by the connected load is simply calculated as the product of the DC voltage times the DC current, that is V*I, given in watts (W). For a fixed resistive load, current is proportional to the applied voltage so the electrical power dissipated by the resistive load will be linear. But in an alternating current (AC) circuit the situation is slightly different as  reactance  affects the behavior of the circuit. For an AC circuit, the power dissipated in watts at any instant in time is equal to the product of the volts and amperes at that exact same instant, this is because an AC voltage (and current) is sinusoidal so changes continuously in both mag...

  Types of batteries All the electrochemical cells and batteries are classified into two types: Primary batteries (non-rechargeable) Secondary batteries (rechargeable) A Primary Battery is one of the simple and convenient sources of power for several portable electronic and electrical devices like lights, cameras, watches, toys etc. As they cannot be recharged electrically, they are of “use and throw” type. Usually, primary batteries are Inexpensive  light weight small and very convenient to use with relatively no or less maintenance. Majority of the primary batteries that are used in domestic applications are single cell type and usually come in cylindrical configuration (although, it is very easy to produce them in different shapes and sizes). A Secondary Battery is also called as Rechargeable Battery as they can be electrically recharged after discharge. The chemical status of the electrochemical cells can be “recharged” to their original status by passing a current throu...

E nergy calculation is straightforward. The unit of electrical energy is the kilowatt-hour (kWh), found by multiplying the power use (in kilowatts, kW) by the number of hours during which the power is consumed. Multiply that value by the cost per kWh, which gives the total energy cost.         Total energy cost = (Power in watts/1000) × hours operating × cost per kWh While the energy calculation is straightforward, there are variables to consider.           -Varying electric rates           -Differences between labeled and actual power           -How many hours a day the device operates           -Different operating modes   *Varying Rates In most communities, energy costs are not constant. Residential rates are often "layered." The more you use, the more you pay. Some utilities even charge by time of day, with lower rates during off-peak hours. *Po...