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# Electric Power

It covers articles related to single and three phase power.

## Power Quality Problems in Power Distribution System

Correcting power quality problems requires an understanding of all power distribution system components and how a problem in one component can cause problems in other components. Distribution system components include transformers, distribution lines, switchboards, and panel boards, disconnects, circuit breakers, fuses, and receptacles to deliver, control, and protect the system. …

## What is a Smart Grid | Components

An electrical grid is a network that delivers electrical power from the power plants where it is generated to customers. See Figure 1. An electrical grid includes wires, substations, transformers, and switches. Definition: A smart grid is an electrical grid that uses computer-based remote control and automation to deliver electrical …

## Electrical Elementary Diagrams

When the circuit components are either large, remote from each other, or numerous in a given electrical-power distribution system or control process drawing, the pictorial wiring diagram is an ineffective way to relay the required information. A different type of drawing, called the elementary diagram, which displays only the electrical …

## Electrical Safety Precautions for Working With Electrical Equipment

In order to avoid the harmful effects of possible electrical shock or electrocution, it is necessary for you or for the practicing electrician to be cautious and follow closely these safety practices: Rule 1: Always consider safety first Safety must be considered first when working with any type of electrical …

## Circuit Breaker Ratings and Specifications | Circuit Breaker Nameplate

A circuit breaker is an electrical device that opens and closes a circuit by non-automatic means and automatically opens a circuit when a predetermined current overload is reached, without damage to itself. Circuit breakers provide protection to circuits, and their function is similar to fuses. A fuse is an electrical …

## Circuit Breaker Types and Their Uses

Low-voltage circuit breakers are typically used in applications such as lighting circuits, motor control centers, feeder circuits and any application in which electrical power needs to be turned on and off and overcurrent protection is required. Medium-voltage circuit breakers are used in many of the same types of applications as …

## Molded Case Circuit Breaker (MCCB) Working Principle

A molded-case circuit breaker (MCCB) is a circuit breaker that uses a molded case to house and supports its current-carrying components as well as to be a part of the insulation system. The working principle of MCCB is discussed in detail in this article. The most common type of MCCB …

## Air Circuit Breaker (ACB): Construction & Working Principle

Low-voltage power circuit breakers (LVPCB) are often referred to as air circuit breakers (ACB). Air circuit breakers are typically of the draw-out design, although they can be bolted directly to the bus. Air circuit breakers are used for applications in which there is a requirement for a more sturdy design …

## Medium Voltage Circuit Breakers Operation

Low- and medium-voltage Vacuum circuit breakers are similar in construction and operation. One of the primary differences between them is that the OCPDs on LVPCBs are mounted on the circuit breakers, while medium-voltage circuit breakers use protective relays, which are typically mounted on the enclosure door. Medium-voltage circuit breakers have …

## Circuit Breaker Schematic Diagram

A schematic diagram is a drawing that shows electrical system circuitry with symbols that depict electrical devices and lines representing conductors. Only qualified persons should review schematic diagrams and perform work on circuit breakers. A qualified person is a person who has special knowledge, training, and experience in the installation, …

## Phase Sequence in Three-Phase System

In a three-phase service supplied by an electrical utility company, all three line voltages have the same magnitude and are displaced from one another by 120°. We can measure the magnitude of these voltages quite readily. However, the magnitudes do not tell us whether VBN leads VAN by 120° or …

The two-phase alternator in Figure 1(a) has two identical loops mounted on the same rotor. Since both loops have the same number of turns and rotate at the same angular velocity, the voltages induced in them have the same magnitude and frequency. Loop A is mounted on the rotor 90° …

## Power Triangle and Power Factor in AC Circuits

Power Triangle The real power in the circuit of Figure 1 can be found from the product of VR and I, and the reactive power from the product of VL and I. Since VL leads VR by 90°, $\begin{matrix}{{V}_{T}}=\sqrt{V_{R}^{2}+V_{L}^{2}} & {} & \left( 1 \right) \\\end{matrix}$ Figure 1 AC circuit …