Introduction A transformer is one of the most vital electrical machines used in power systems. Its primary role is to step up or step down voltage levels, making power transfer more reliable and economical. Transformers ensure smooth and efficient power transmission from generating stations to end users, reducing waste and maintaining system stability. The transformer’s performance … Read more
When a transformer is supplied with a fixed applied voltage at its primary winding, the secondary terminal voltage does not always remain constant. If the magnitude or power factor of the load connected to the secondary side changes, a corresponding change in is observed. This change occurs due to the voltage drops across the winding … Read more
1. Introduction Transformers are vital components in electrical power systems, used to step up or step down voltages efficiently. However, a real transformer is not perfect — it has losses and non-idealities. The equivalent circuit is a simplified model that represents these imperfections, helping engineers analyze and design transformers effectively. 2. What is an Equivalent … Read more
1. Introduction A transformer is a key device in electrical power systems. It moves electrical energy from one circuit to another using electromagnetic induction. In an ideal world, transformers would work perfectly with no losses or voltage drops. But in real life, they have limits. One important factor is leakage reactance. This affects how well … Read more
Operation of Transformer in On-Load Condition To understand the operation of a transformer in load, let us first recall its on-load condition. In the on-load state, when an input voltage is applied across the primary winding, a small on-load current flows. This current establishes a magnetic flux in the transformer core. What is a Transformer? … Read more
Difference Between Ideal and Practical Transformer When it comes to learning about transformers, two terms often pop up: ideal transformer and practical transformer. They sound similar, but there’s a big difference between them. Let’s explore it in a way that’s easy to understand. What is a Transformer? A transformer is an electrical device that transfers … Read more
Understanding the brake test of dc motor: Imagine trying to find out how well a DC motor is working—how much of the electrical power it uses turns into useful mechanical work. One easy and direct way to check this in a lab is by do something called a Brake Test. Let’s break it down in … Read more
Two-Point Starter A two-point starter is used for starting DC series motors. It is a simple device that helps control the starting current to prevent damage to the motor. A Two-Point Starter is a simple device used FOR safely starting a DC series motor. When a motor starts, it can draw a large amount of … Read more
Three-Point Starter A three-point starter is commonly used to safely start DC shunt motors. Just like the two-point starter, it controls the high inrush of current when the motor is switched on. But this one comes with an added feature—overload and no-voltage protection, making it more reliable. What is a Three-Point Starter? The name “three-point” … Read more
DC Motor Starter: DC motors, especially those below 1 HP (0.746 kW), can often be directly connected to a power supply. This is possible because smaller motors have a relatively high armature resistance (Ra), which naturally limits the starting current. Some examples include: However, this direct online starting method cannot be used with larger motors … Read more
What Is Speed Regulation? Think about riding a bicycle. When you’re going downhill with no backpack, it’s super fast and smooth. But going uphill with a heavy bag? How to calculate the speed regulation of DC motors? DC motors act the same way. When there’s no load, they run fast. When there’s a heavy load, … Read more
Introduction Electrical outlets form an essential part of residential and commercial electrical infrastructure. They provide the interface between electrical devices and a building’s power distribution system. For students pursuing electrical engineering or a related field, understanding the principles and practices of electrical outlet wiring is crucial not only for practical installations but also for developing … Read more
Brushless DC (BLDC) Motor Brushed DC motors are older types of motors that utilize small components called brushes and a commutator to facilitate the flow of electricity. But these parts rub against each other and cause sparks, which makes them wear out quickly. They also have wires on both the inside and outside parts of … Read more
Complete Guide to Swinburne Test DC Machine The Swinburne Test is a simple and useful method to check the performance of DC motors. It helps us know how much energy the motor uses and how efficient it is. This guide will explain everything in a very simple way. Let’s learn step by step! 1. Step-by-Step … Read more
How to Speed Control of DC Shunt Motors: While controlling the speed of a DC shunt motor may seem like a daunting task, with a little bit of guidance, it can be very simple. This tutorial will break this down step by step with simple language and relevant illustrations. 🔌 A DC Shunt Motor: A … Read more
Applicable Groups: UP Polytechnic Counseling Group A, B, C, D, F, G, H, I, K1 to K8, and L UP Polytechnic Counseling Date 2025 Main Online Counseling (1st Phase) Eligible Candidates: Uttar Pradesh Candidates Round 1 Choice Filling: 27 June to 2 July 2025 Seat Allotment Result: 3 July 2025 Freeze/Float Option + Fee Payment: … Read more
What is DC Motor Speed Control? Every electric motor has a fixed speed written on its nameplate. This is called the rated speed. It tells us how fast the motor is supposed to run when it’s working normally. But in real life, things keep changing. When the load on the motor changes — like if … Read more
अगर आप यूपी के छात्र हैं और 2025 में स्कॉलरशिप के लिए आवेदन करना चाहते हैं, तो ये जानकारी आपके बहुत काम की है। हम यहां आपको बिलकुल साफ, आसान और असली भाषा में बताएंगे कि इस बार स्कॉलरशिप कब शुरू हो रही है, कैसे आवेदन करना है, और कौन-कौन छात्र इसके लिए पात्र हैं। … Read more
What is a Water Treatment Plant (WTP)? Water is one of the most essential elements of life, but not all water is suitable for use in homes, industries, or agriculture. In many regions, natural water contains dissolved minerals, dust, microbes, and other harmful substances. These impurities can cause damage to pipelines, reduce the efficiency of … Read more
Electricity is the invisible energy that powers almost everything around us. From the smallest home appliance to the most advanced hospital life-support system—modern life relies entirely on electricity. But electricity is not always reliable. Power failures, voltage fluctuations, or even short interruptions can cause data loss, machine damage, or even life-threatening situations in critical areas … Read more
Retrofit Emission Control Devices: Clean air is not just important. It is life. Every breath we take should be pure and safe. But sadly, the air around us is filled with harmful gases and tiny particles. These come from vehicles, factories, and other machines that burn fuel. One strong and smart solution to reduce this … Read more
What are Measuring Instruments? Measuring instruments are the tools that help us see and understand what’s happening inside an electric circuit. They show us things we can’t see with our eyes – like how much current is flowing or how much voltage is present. Now let’s understand their types. Types of Measuring Instruments There are … Read more
Flushing Cistern A flushing cistern is a simple water tank that stores water and then releases it quickly to clean the toilet or urinal after use. When someone uses the toilet, we need water to wash away the waste. That’s exactly what a flushing cistern does. It holds clean water and, with just one push … Read more
Top 5 Most Popular and Promising Polytechnic Courses In today’s fast-moving world, education is not just about books and classrooms. It’s about skills. It’s about learning something real. And one of the best ways to do that is by joining a diploma course, also known as polytechnic. These diploma courses are short, practical, job-oriented, and … Read more
Compensating Winding When a motor or generator is working, the current inside the armature (the rotating part) keeps changing, especially when the load changes suddenly or becomes too heavy. These changes in current create something called a cross magnetizing effect, which means the magnetic field gets pushed to one side. Now imagine this — every … Read more
Armature Reaction – Definition When a motor or generator is running, there are two types of magnetic fields inside it. One magnetic field comes from the main field winding (which is supposed to be there), and the second one comes from the armature winding (the rotating part). Now, when the armature winding carries current, it … Read more
Commutation in dc machine Let’s imagine the heart of a DC generator — the armature — is always spinning. As it spins, the current in its wires keeps changing direction. That means it actually creates alternating current (AC), not direct current (DC) at first. But we call it a DC generator — why? That’s because … Read more
DC Shunt Generator A DC Shunt Generator is a special type of DC generator that is commonly used because it works on its own without needing any outside power to get started. It gives a stable voltage, whether you’re using it a little or a lot. Let’s understand characteristics of dc shunt generator how it … Read more
Types of Armature Winding When we talk about armature winding in electric machines (like motors or generators), we’re simply talking about how the wires are arranged inside the machine to carry current. These wires connect at a part called the commutator. Now, depending on how these wires are connected at the ends, armature winding is … Read more
A DC machine is an electromechanical device that converts electrical energy into mechanical energy, or vice versa, using direct current (DC). It works on the fundamental principle of electromagnetic induction, which was discovered by Michael Faraday. DC machines are classified into two main types: DC generators and DC motors. A DC generator converts mechanical energy … Read more
What is Transmission Line? A transmission line is like a big electric road. Just like trucks carry goods from one city to another, a transmission line carries electricity from power stations to our homes, schools, offices, and factories. Simple Example: Imagine a water pipe. Water flows through the pipe and reaches your tap. In the … Read more
Electrical Power Distribution System The distribution system is the part of the electric supply network that delivers electricity from the distribution substation to the end consumers (homes, shops, farms, etc.). An electrical distribution system is a network of equipment that carries electricity from high-voltage transmission lines to homes, businesses, and other users. It acts as … Read more
Measurement of Power in Three-Phase Systems A wattmeter is a device used to measure the average or real power in AC circuits. While the method for measuring single-phase power is discussed in Chapter 1, this section focuses on the measurement of three-phase power. There are three main methods used for measuring the active (real) power … Read more
ideal Voltage and Current Sources Electricity is a part of our daily life. We use it to light our homes, run our fans, charge our phones, and power our TVs. But have you ever thought — where does this electricity come from? That’s where voltage sources and current sources come in. Let’s understand them in … Read more
Are you looking for the Top 20 Polytechnic Colleges in UP Government? If yes, then you’ve come to the right place! Whether you’re a student, a parent, or just someone curious about technical education, this guide will help you understand everything in the simplest and clearest way. Polytechnic colleges are a great option for students … Read more
Open circuit and short circuit What is an Open Circuit? | An open circuit means there is a break or gap in the path where electricity should flow. Imagine a road where a bridge is broken — cars can’t pass through it. In the same way, when a wire or part of the circuit is … Read more
Introduction to Magnetic Circuits We all know that magnets can pull things like pins or nails. But have you ever wondered how this invisible pull works inside machines like fans, motors, or transformers? Well, it’s all about something called a magnetic circuit. Just like electric current flows in a loop through wires in an electric … Read more
Magnetic Hysteresis When we take a piece of magnetic material—like iron—and magnetise it first in one direction, and then in the opposite direction, something interesting happens. The magnetic strength inside the material does not follow the applied force exactly. Instead, it lags behind. This delay is called Magnetic Hysteresis. 🔄 What is Magnetic Hysteresis? Magnetic … Read more
Magnetic Flux Density Have you ever seen how magnets pull things without touching them? This invisible force spreads out in space like magic. But how do we measure this magnetic power in a certain area? That’s where Magnetic Flux Density comes in. 🌟 What is Magnetic Flux Density? Magnetic Flux Density is a way to … Read more
Definition of Parallel Plate Capacitor A parallel plate capacitor is a device made of two flat, conductive plates placed parallel to each other with a small gap between them. This gap is usually filled with air or a material called a dielectric. When we connect a battery or voltage source across the plates, one plate … Read more
