Indepth Electrical engineering

Locked Rotor Current and Torque in Induction Motors What is Locked Rotor Current? Locked rotor current (LRC) is the maximum current drawn by an induction motor when its rotor is not rotating (locked condition) . At startup, since the motor speed is zero, the slip is 1 (100%), and the motor draws its highest current. This current is usually 3–8 times the full load current (FLC) . As the motor accelerates, the current gradually reduces until it stabilizes at the rated full load current. LRC depends on the motor design, type, and supply voltage (higher supply voltage → lower current for the same power). 👉 In other words, "locked rotor current" is the current drawn if the motor is energized but prevented from turning. Equivalent Circuit at Locked Rotor Condition At locked rotor, each stator phase behaves like a series R–L circuit . Resistance (R): Copper loss component. Inductance (L): Reactance due to leakage ...

Transmission Towers: Parts, Design, and Types Explained High-voltage power transmission is the backbone of modern electricity networks. To transmit power over long distances, transmission lines are laid, and these lines are supported by transmission towers , also known as pylons. Transmission towers serve two primary purposes: To safely separate high-voltage conductors from surroundings and from each other. To keep conductors at sufficient height above the ground, ensuring safety and reliability. Most overhead transmission lines carry three-phase power using three conductors or bundles of conductors. Typically, ACSR (Aluminum Conductor Steel Reinforced) is used: a steel core provides strength, while surrounding aluminum wires offer high conductivity with low resistance. Key Parts of a Transmission Tower A transmission tower is an engineered steel structure designed to withstand natural calamities, wind loads, and conductor tensions . It is made of several essentia...

Cable Selection Guide: Voltage, Current Capacity, Insulation, and Installation Methods  Learn how to select the right electrical cables based on voltage level, current carrying capacity, insulation type, installation method, number of cores, and environmental conditions. Introduction Selecting the right power cable is crucial in electrical systems to ensure safety, efficiency, and long-term reliability. Cable selection depends on various factors such as voltage level, current carrying capacity (ampacity), insulation type, number of cores, installation method, and environmental conditions . Using the wrong cable can lead to overheating, excessive voltage drop, or even failure of the electrical system. 1. Cable Selection According to Voltage Level Cables are categorized based on their nominal voltage ratings. The classification is as follows: Low Tension (LT) Cables : Up to 1000 V High Tension (HT) Cables : Up to 11 kV Super Tension Cables : From 22 kV to 33 kV Ex...

High Tension (HT) Cables: Types, Components, and Insulation Levels High Tension (HT) cables are the backbone of modern electrical power systems. Electricity is transmitted and distributed over long distances using HT cables or conductors , making them an indispensable part of power networks. The most commonly used HT cables are XLPE (Cross-Linked Polyethylene) cables , which offer high insulation strength, thermal stability, and longer service life compared to traditional PVC cables. 🔹 Types of HT Cables HT cables are classified mainly into two types: Single Conductor HT Cable Contains a single conductor per cable. For a three-phase system, three separate cables are required. Three Conductor HT Cable Contains three conductors within a common jacket. Compact design, often used where space is limited. 🔹 Components of HT Cables Although HT cables may look different externally, they all share five essential parts : Conductor (Copper or Aluminum) ...

Cable Glands: Types, Applications, and Industrial Standards Cable glands are an essential component in electrical and instrumentation installations. They provide mechanical support, environmental protection, and safety for cables entering panels or enclosures. Functions of Cable Glands Cable glands are used for the following purposes: 1.       Strain relief – Prevents tension and stress at cable termination points. 2.       Earthing and grounding – In case of armored cables, they ensure effective bonding. 3.       Cable entry – Provides safe and sealed entry into electrical panels, junction boxes, and enclosures. Types of Cable Glands Different types of glands are used based on cable type and application: 1.       Indoor Glands (Brass material) – For general indoor use. 2.       Outdoor Glands (Brass material) – With wea...

Earth Leakage Circuit Breaker (ELCB) – Types, Working, and Difference from RCCB 🔹 Introduction E lectrical safety is one of the most crucial aspects of any power system. A significant share of accidents occur due to leakage currents that remain undetected by conventional circuit breakers. To overcome this risk, Earth Leakage Circuit Breakers (ELCBs) were developed. Over time, however, the traditional Voltage-operated ELCBs have been replaced by modern Current-operated devices (RCCB/RCD), which are more effective in protecting human life and installations. This article explains: What is an ELCB? Types of ELCB (Voltage vs. Current) Why Voltage-operated ELCBs are obsolete Differences between ELCB and RCCB Applications and rating selection 🔹 What is an Earth Leakage Circuit Breaker (ELCB)? An ELCB is a safety device designed to disconnect the supply when leakage currents are detected. Leakage current may occur due to insulation fail...