Sometimes we encounter a diversity of instrument signal standards in one control system. Such is the case with…
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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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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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While 50 and 51 (instantaneous and time overcurrent) relay functions monitor line current magnitude and guard…
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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 term “grid” refers to the conductors and equipment interconnecting power sources to power…
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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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DC electric motors generate torque by a reaction between two magnetic fields: one field established by…
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Three-phase AC is the dominant mode of electric power generation and distribution in modern societies.…
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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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Those familiar with industrial instrumentation will find much within the electric power industry remarkably…
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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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“Polyphase” means “many phases,” describing a form of AC electrical system where…
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The two “process variables” we rely on most heavily in the field of electrical measurement and…
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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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Electrical power grids primarily consist of three-phase AC circuits. This means most power lines (transmission…
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Classical mechanics (often called Newtonian mechanics in honor of Isaac Newton) deal with forces and motions…
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Every flow-measuring instrument exploits a physical principle to measure the flow rate of fluid stream.…
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Filled-bulb systems exploit the principle of fluid expansion to measure temperature. If a fluid is enclosed in…
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When a high-energy photon strikes an atom, it may eject one of the lower-level electrons from its shell,…
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In addition to directly performing logic functions, electromechanical relays may also be used as interposing…
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PID control can be a confusing concept to understand. Here, a brief summary of each term within PID (P. I, and…
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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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In order to provide an interface between the internal (digital) world of a computer and the external (analog)…
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“As to methods there may be a million and then some, but principles are few. The man who grasps…
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Any physical location in an industrial facility harboring the potential of explosion due to the presence of…
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A damper (otherwise known as a louvre) is a multi-element flow control device generally used to throttle large…
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Suppose we wished to measure the consumption of propane over time for a large propane storage tank supplying a…
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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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Solids tend to expand when heated. The amount that a solid sample will expand with increased temperature…
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A completely different way of measuring liquid level in vessels is to bounce a traveling wave off the surface…
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Many years ago, when I was first learning about electricity, I happened to discover a length of coaxial…
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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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What is Calibration? To calibrate an instrument means to check and adjust (if necessary) its response so the…
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There are several different methods useful for causing an AC induction motor to brake, or slow down: DC…
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Programmable logic controllers are essentially nothing more than special-purpose, industrial computers. As…
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