While 50 and 51 (instantaneous and time overcurrent) relay functions monitor line current magnitude and guard…
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The transformer is one of the most important components in all of AC circuitry. Principally used to…
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By definition, a source is a device delivering energy into a system, while a load is a device extracting…
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A form of protection against faults on long-distance power lines is called distance relaying, so named because…
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Three-phase AC is the dominant mode of electric power generation and distribution in modern societies.…
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Electrical power grids primarily consist of three-phase AC circuits. This means most power lines (transmission…
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One of the fundamental laws of electric circuits is Kirchhoff’s Current Law, which states the algebraic…
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The term “grid” refers to the conductors and equipment interconnecting power sources to power…
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Circuit breakers used in residential, commercial, and light industrial service are self-tripping devices: they…
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“Polyphase” means “many phases,” describing a form of AC electrical system where…
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Disconnect Switches Disconnects are switches designed to isolate sections of a power system in case of damage…
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Those familiar with industrial instrumentation will find much within the electric power industry remarkably…
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Current is the name we give to the motion of electric charges from a point of high potential to a point of low…
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Since we often use electricity to convey energy from one location to another, it is important to be able to…
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The two “process variables” we rely on most heavily in the field of electrical measurement and…
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In the United States, the ANSI and IEEE organizations have standardized a set of numerical codes referring to…
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The Law of Mass Conservation states that matter can neither be created nor destroyed. The Law of Energy…
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A limit switch detects the physical motion of an object by direct contact with that object. An example of a…
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Learning is not merely a process of information transfer. It is first and foremost a transformation of…
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Any conductor possesses a characteristic called inductance: the ability to store energy in the form of a…
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Most pneumatic instruments use a simple but highly sensitive mechanism for converting mechanical motion into…
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Phasors are to AC circuit quantities as polarity is to DC circuit quantities: a way to express the…
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Regulating the electric power sent to an electric motor is a task performed by high-speed switching…
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The two “process variables” we rely on most heavily in the field of electrical measurement and…
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A fluid is any substance having the ability to flow: to freely change shape and move under the influence of a…
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The dispersion of visible light into its constituent colors goes all the way back to the 17th century with…
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One of the simplest classes of temperature sensor is one where temperature effects a change in electrical…
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Labwork is an essential part of any science-based curriculum. Here, much improvement may be made over the…
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Fluid pressure exerts force on any surface area it contacts, as described by the formula \(F = PA\). One…
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Flow, by definition, is the passage of material from one location to another over time. So far this chapter…
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Since we often use electricity to convey energy from one location to another, it is important to be able to…
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There is much to be said for neatness of assembly in electrical signal wiring. Even though the electrons…
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A machine in the broad sense of the word is any device designed to translate some form of energy into useful…
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Displacer level instruments exploit Archimedes’ Principle to detect liquid level by continuously…
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A hand switch is exactly what the name implies: an electrical switch actuated by a person’s hand motion.…
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The fundamental principle of electromagnetism is that an electric current will create a magnetic field at…
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A chemical reaction resulting in a net release of energy is called exothermic. Conversely, a chemical reaction…
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The following photograph shows a large air blower in a wastewater treatment facility equipped with a…
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The following animation shows how a radio-energy pulse travels down and then up the waveguide of a guided-wave…
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The following animation shows a rotating phasor in three-dimensional form. The phasor rotates in a complex…
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As a general rule, high achievement only takes place in an atmosphere of high expectations. Sometimes these…
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Once while working as an instrument technician in an aluminum foundry, a mechanic asked me what it was that I…
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Flow, by definition, is the passage of material from one location to another over time. So far this chapter…
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Feedback Control System Components Before we begin our discussion on process control, we must define a few key…
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Electromechanical relays may be connected together to perform logic and control functions, acting as logic…
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Much of our knowledge about atomic structure comes from experimental data relating the interaction between…
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A 4 to 20 mA current signal represents some signal along a 0 to 100 percent scale. Usually, this scale is…
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A limit switch detects the physical motion of an object by direct contact with that object. An example of a…
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Mechanical pressure-sensing elements include the bellows, the diaphragm, and the bourdon tube. Each of these…
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Level gauges are perhaps the simplest indicating instrument for liquid level in a vessel. They are often found…
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Learning is not merely a process of information transfer. It is first and foremost a transformation of…
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A design-based fortification is one rooted in technical details of system architecture and functionality. Some…
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Area refers to the size of two-dimensional surface. Volume refers to the size of a three-dimensional space. To…
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Self-balancing mechanisms consisting solely of a baffle/nozzle detector coupled to a feedback bellows, while…
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Electrical Resistance Resistance (\(R\)) is the dissipative opposition to an electric current, analogous to…
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Programmable logic controllers are essentially nothing more than special-purpose, industrial computers. As…
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