The following animation shows how the “rotating” magnetic field of a three-phase AC induction…
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A simple control system drawn in block diagram form looks like this: Information from the measuring device…
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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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Modern DC and AC motor drives provide features useful when using electric motors as final control elements.…
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An electric motor is often used as a discrete control element in a control system if driving a pump, conveyor…
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DC electric motors generate torque by a reaction between two magnetic fields: one field established by…
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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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The simplest form of 4-20 mA current loop is the type used to represent the output of a process controller,…
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The key to understanding how three-phase electric motors work is to have an accurate mental picture of the…
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AC induction motors are based on the principle of a rotating magnetic field produced by a set of stationary…
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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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The simple PLC ladder diagram (LD) commands consist of contacts and coils, arranged in sequences that mimic…
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Modern DC and AC motor drives provide features useful when using electric motors as final control elements.…
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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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Imagine a liquid-level control system for a vessel, where the position of a level-sensing float sets the…
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The simplest form of 4-20 mA current loop is the type used to represent the output of a process controller,…
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Virtually any mass above absolute zero temperature emits electromagnetic radiation (photons, or light) as a…
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In order for any PID controller to be practical, it must be able to do more than just implement the PID…
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Perhaps the most important rule of controller tuning is to know the process before attempting to adjust the…
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Negative feedback systems, in general, tend to cause confusion for those first learning their fundamental…
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In the United States, the most common language used to program PLCs is Ladder Diagram (LD), also known as…
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Non-dispersive analysis, while newer in discovery than dispersive analysis (Isaac Newton’s 17th-century…
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The purpose of a control valve actuator is to provide the motive force to operate a valve mechanism. Both…
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In addition to directly performing logic functions, electromechanical relays may also be used as interposing…
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Perhaps the most basic and necessary protective relay function is overcurrent: commanding a circuit breaker to…
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A bridge circuit is basically a pair of voltage dividers where the circuit output is taken as the difference…
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As discussed at the beginning of this chapter, instrumentation safety may be broadly divided into two…
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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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The reason why a pneumatic control valve’s stem position corresponds linearly to the amount of air…
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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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A technological advance introduced in the late 1980’s was HART, an acronym standing for Highway…
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DC electric motors generate torque by a reaction between two magnetic fields: one field established by…
Textbook
AC induction motors are based on the principle of a rotating magnetic field produced by a set of stationary…
Textbook
There are several different methods useful for causing an AC induction motor to brake, or slow down: DC…
Textbook
Modern DC and AC motor drives provide features useful when using electric motors as final control elements.…
Textbook
Two extremely important principles in electric circuits were codified by Gustav Robert Kirchhoff in the year…
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Circuit breakers used in residential, commercial, and light industrial service are self-tripping devices: they…
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The majority of flowmeter technologies operate on the principle of interpreting fluid flow based on the…
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Perhaps the most important rule of controller tuning is to know the process before attempting to adjust the…
Textbook
A simple control system drawn in block diagram form looks like this: Information from the measuring device…
Textbook
The simple PLC ladder diagram (LD) commands consist of contacts and coils, arranged in sequences that mimic…
Textbook
Many traditional flowmeter technologies respond to the volumetric flow rate of the moving fluid.…
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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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“Radio” systems use electromagnetic fields to communicate information over long distances through…
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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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Control strategies such as cascade, ratio, feedforward, and those containing limit and selector functions can…
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Fieldbus devices require far more attention in their initial setup and commissioning than their analog…
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Much has been written about the benefits of robust PID control. Increased productivity, decreased equipment…
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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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