The term “grid” refers to the conductors and equipment interconnecting power sources to power…
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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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Disconnect Switches Disconnects are switches designed to isolate sections of a power system in case of damage…
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The two “process variables” we rely on most heavily in the field of electrical measurement and…
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Those familiar with industrial instrumentation will find much within the electric power industry remarkably…
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“Polyphase” means “many phases,” describing a form of AC electrical system where…
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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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Electrical power grids primarily consist of three-phase AC circuits. This means most power lines (transmission…
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Three-phase AC is the dominant mode of electric power generation and distribution in modern societies.…
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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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While 50 and 51 (instantaneous and time overcurrent) relay functions monitor line current magnitude and guard…
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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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Circuit breakers used in residential, commercial, and light industrial service are self-tripping devices: they…
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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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Since we often use electricity to convey energy from one location to another, it is important to be able to…
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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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Valve actuators provide force to move control valve trim. For precise positioning of a control valve, there…
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Much of our knowledge about atomic structure comes from experimental data relating the interaction between…
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A level switch is one detecting the level of liquid or solid (granules or powder) in a vessel. Level switches…
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This section shows some of the many instrument symbols found in different types of technical diagrams used to…
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Perhaps the most basic and necessary protective relay function is overcurrent: commanding a circuit breaker to…
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An important type of “accessory” relay, especially for legacy electromechanical protective relays,…
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Classical mechanics (often called Newtonian mechanics in honor of Isaac Newton) deal with forces and motions…
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A limitation inherent to pneumatic valve actuators is the amount of air flow required to or from the actuator…
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A technological advance introduced in the late 1980’s was HART, an acronym standing for Highway…
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A pressure switch is one detecting the presence of fluid pressure. Pressure switches often use diaphragms or…
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A variety of problem-solving techniques have been presented for students over the years which are all helpful…
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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 proximity switch is one detecting the proximity (closeness) of some object. By definition, these switches…
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A design-based fortification is one rooted in technical details of system architecture and functionality. Some…
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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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The reason why a pneumatic control valve’s stem position corresponds linearly to the amount of air…
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Regardless of valve type, all stem-actuated control valves require some form of seal allowing motion of the…
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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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Imagine a liquid-level control system for a vessel, where the position of a level-sensing float sets the…
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Electrical power grids primarily consist of three-phase AC circuits. This means most power lines (transmission…
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Layer 1 of the OSI Reference Model is where we define the “physical” elements of a digital data…
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To better understand the design and operation of self-balancing pneumatic mechanisms, it is helpful to examine…
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Mechanical pressure-sensing elements include the bellows, the diaphragm, and the bourdon tube. Each of these…
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In order to provide an interface between the internal (digital) world of a computer and the external (analog)…
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An important design parameter of a control valve is the position it will “fail” to if it loses…
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Learning PLC programming is a very important skill. If your job involves programming, then you will likely…
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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 photograph shows a large air blower in a wastewater treatment facility equipped with a…
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A great many precision instruments use the principle of balance to measure some quantity. Perhaps the simplest…
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As described earlier in this chapter, calibration refers to the adjustment of an instrument so its output…
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Recall that an exothermic chemical reaction is one that releases a net sum of energy, as opposed to an…
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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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In November of 2007 a new computer virus was submitted to a virus scanning service. The purpose of this new…
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The final step in treating wastewater before releasing it into the natural environment is to kill any harmful…
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Certain types of nuclear radiation easily penetrates the walls of industrial vessels, but is attenuated by…
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Process analyzers measure the concentration of specific substances for the purpose of measuring and/or…
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(Will be addressed in future versions of this book)
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Constructing PID control systems using discrete components is a fairly simple method involving operational…
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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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Solids tend to expand when heated. The amount that a solid sample will expand with increased temperature…
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