Indepth Electrical engineering

Comparison of Motor Starters: Advantages and Disadvantages Motor starters are essential in controlling the starting current, voltage, and torque of induction motors. Each type of starter has its own application area, benefits, and limitations . Below is a detailed comparison of commonly used starters: 1. Direct-On-Line (DOL) Starter Advantages Very simple design and operation . Low maintenance due to minimal components. Low initial cost . Ease of installation with straightforward circuitry. Suitable for small motors (up to ~10 kW) . Disadvantages Very high inrush starting current (6–8 times full load current). Causes voltage dips in weak supply systems. Not suitable for larger motors (>10 kW) . No power saving during operation. Short acceleration period , making it unsuitable for heavy loads. 2. Star-Delta Starter Advantages Reduces starting current to about 1/3 of DOL value . Prov...

Power Plant Everyone electrical engineer has very much interest in power generation. Now let's study 1st what is power plant??? A power plant is that industry where power get generated. Power generation usually takes place in Megawatts. From there power is power transmission is done and provided at palaces as per requirements. Power plants requires huge land and water that is why power plants are usually located at a far away distance from main city. For this reason, a power generating station has to not only take care of efficient generation but also the fact that the power is transmitted efficiently over the entire distance. And that’s why, the transformer switch yard to regulate transmission voltage also becomes an integral part of the power plant. At the center of it, however, nearly all power generating stations has an A.C. generator or an alternator, which is basically a rotating machine that is equipped to convert energy from the mechanical domain (rotating tu...

Chemical Earthing: Working, Treatment Methods, and Benefits Introduction Earthing is one of the most critical safety measures in any electrical system. Traditional earthing methods often require regular maintenance and may not provide consistently low resistance in high-resistivity soil conditions. To overcome these limitations, Chemical Earthing has become increasingly popular in industrial, commercial, and residential installations due to its long life, minimal maintenance, and reliable performance . Why Chemical Earthing is needed? In conventional earthing systems, multiple rods or electrodes may still fail to achieve a low resistance path to ground—especially in rocky or high-resistivity soil. This problem can be solved by artificial treatment of earthing pits , where the soil resistivity around the electrode is reduced by mixing it with conductive substances. Traditional Earthing Treatment Materials In conventional practice, substances like the following are a...

Miniature Circuit Breakers (MCBs) – Working & Internal Parts What is an MCB? An MCB (Miniature Circuit Breaker) is an electromechanical device that protects an electrical circuit from over-current. The over-current in a circuit may occur due to: Short circuit Overload Faulty design Unlike fuses, MCBs do not need replacement after tripping. Instead, they can be reset manually, offering better safety, convenience, and cost-effectiveness . MCBs are widely used in domestic and industrial applications , particularly for lighting loads and small motor loads . Working Principle of MCB The working of an MCB is straightforward: An MCB acts like a switch that turns off automatically when the current exceeds the permissible limit. It is designed to protect against over-current and over-temperature faults . How it works: There are two contacts: fixed and movable . When the current exceeds the set value, the solenoid pushes the movable contact to open ...

Vacuum Circuit Breaker (VCB): Working Principle, Operation, and Maintenance Guide A Vacuum Circuit Breaker (VCB) is one of the most reliable and widely used switchgear technologies for medium-voltage applications. It extinguishes arc inside a vacuum , where no medium (oil, gas, or air) is required, making it safer and more eco-friendly compared to conventional circuit breakers. Working Principle of VCB The main function of any circuit breaker is to quench the arc that forms when contacts open under load. In a VCB: The arc quenching medium is vacuum , with pressure maintained around 10⁻⁶ bar . When contacts separate, a metal vapor arc is formed at the last contact point. At current zero, the arc is extinguished as the vapor condenses back on the contacts. The high dielectric strength of vacuum (8× air, 4× SF₆) prevents re-ignition. This ensures fast arc extinction and minimizes contact erosion. Construction of Vacuum Interrupter A typical vacuum interrupter c...

Percentage Impedance of a Transformer (Z%) The percentage impedance (Z%) of a transformer is one of the most important parameters marked on its nameplate. It influences voltage regulation, fault levels, and load sharing when transformers are connected in parallel. Definition The percentage impedance of a transformer is: The voltage drop at full load caused by the resistance and leakage reactance of the windings, expressed as a percentage of the rated voltage. Alternatively, it can be defined as the percentage of rated terminal voltage required to circulate full-load current under short-circuit conditions. Measurement of Transformer Impedance Transformer impedance is measured by performing a short-circuit test : One winding of the transformer is short-circuited. A reduced voltage (at rated frequency) is applied to the other winding. The voltage is gradually increased until the rated full-load current flows through the windings. The percentage impedance ...

Strain Insulator Strain insulators working principle is same as that of suspension insulators and they have only difference is that when insulator used in vertical position then it is known as suspension insulator and when used in horizontal position then it is known as strain insulator.  When there is a dead end or there is a sharp corner in transmission line, the line has to sustain a great tensile load of conductor or strain. A   strain insulator   must have considerable mechanical strength as well as the necessary electrical insulating properties. Rated System Voltage Number of disc insulator used in strain type tension insulator string Number of disc insulator used in suspension insulator string 33KV 3 3 66KV 5 4 132KV 9 8 220KV 15 14 Stay Insulator   For low   voltage   lines, the stays are t...