Microgrid: Advantages, Structure, & Applications

A microgrid is a small electricity generation and distribution system containing distributed generation, energy storage systems, loads and monitoring and protection devices.  It is an autonomous system that is self-controlled and self-managed. An energy microgrid provides users thermal energy for heating and cooling in addition to electricity. A fundamental feature …

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Magnetic Motor Starter Control Circuit

Magnetic motor starters are used to turn motors on and off and provide overload protection. A magnetic motor starter also provides additional control contacts (NO and NC auxiliary contacts) in addition to power contacts (L1/T1, L2/T2, L3/T3) used to switch the motor on and off. Magnetic motor starters work well …

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AC and DC Contactor Working Principle

AC or DC contactors

AC contactor assemblies may have several sets of contacts. DC contactor assemblies typically have only one set of contacts. See Figure 1. In three AC contactors, all three power lines must be broken. This creates the need for several sets of contacts. For multiple contact control, a T-bar assembly allows …

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Manual Motor Starter: Working & Applications

A manual starter is a contactor with an added overload protective device. Manual starters are used only in electrical motor circuits. The primary difference between a manual contactor and a manual starter is the addition of an overload protective device. See Figure 1. Figure 1. A manual starter is a …

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Manual Contactor: Working Principle & Wiring Diagram

A manual contactor is a control device that uses pushbuttons to energize or de-energize the load connected to it. See Figure 1. A manual contactor manually opens and closes contacts in an electrical circuit. Manual Contactor Working Manual contactors cannot be used to start and stop motors because they have …

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Single & Three Phase Transformer Connections

Figure 3. Functional operation of a single-phase isolation transformer

Transformers may be connected in various configurations depending on the application. Configurations consist of single-phase and three-phase connections. Single-phase connections are typically found in residential applications, while three-phase connections are found in commercial and industrial applications. High voltage transformer windings are marked H1, H2, etc., and low voltage transformer windings …

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Solar Tracking System: Cost & Benefits

Heliostat Measurement

Many solar systems are designed to track, or follow, the sun’s movement across the sky. Tracking devices are categorized by the number of axes (either single-axis or dual-axis) that turn. Both types can follow the daily east-west motion of the sun, but only dual-axis trackers can track the seasonal north-south …

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Grid Energy Storage Systems: Basics & Characteristics

Energy Storage Systems (ESSs) are evolving as a viable technical and economical solution for improving both short-term and long-term grid operations. Increased peak power demand, limited generation capacity, the variability of renewable energy generation, and transmission and distribution issues can be addressed, in principle, with ESSs.  Different types of ESSs …

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Fuel Cell: Characteristics Curve & Losses

Typical characteristic curves of a PEMFC

In this section, the properties and control characteristic curve of the fuel cells are examined for designing the overall power conversion system to obtain the required voltage and power output for various applications. Fuel Cell Losses Several sources contribute to irreversible losses in a practical fuel cell. The losses, which …

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Wind Turbine Components and Functions

Wind turbine components

Wind turbines are categorized based on the orientation of their spin axis into horizontal-axis wind turbines (HAWT) and vertical-axis wind turbines (VAWT). VAWT have their rotor shaft transverse to the wind (but not necessarily vertical), and the main components are located at the base of the turbine; that is, the …

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Residential Photovoltaic (PV) System Design

The task of designing Photovoltaic (PV) systems is a very tricky process due to the fact that PV panels are still relatively expensive and energy production is very sensitive to atmospheric conditions and the physical location. In the case of ground-mounted PV systems, one can choose the optimum tilt angle …

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Photovoltaic (PV) Cell: Characteristics and Parameters

I-V Characteristics of a PV Cell

PV cell characterization involves measuring the cell’s electrical performance characteristics to determine conversion efficiency and critical parameters. The conversion efficiency is a measure of how much incident light energy is converted into electrical energy. The optimum operating point for maximum output power is also a critical parameter, as is a …

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Transformer: Definition, Working, Losses, Efficiency

Transformers are used today in almost every electrical system to either step up, step down, or isolate one voltage level from another. The extensive use of transformers started after what is known in the electrical field as the “War of Currents.” Thomas Edison believed that the U.S. power distribution system …

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