AC Motor Braking

Textbook

There are several different methods useful for causing an AC induction…

Use of Line Reactors

Textbook

Regulating the electric power sent to an electric motor is a task…

AC Motor Speed Control

Textbook

AC induction motors are based on the principle of a rotating magnetic…

Cascade Control

Textbook

A simple control system drawn in block diagram form looks like this:…

Rotating Magnetic Fields in Three-phase AC Induction Motors

Textbook

The following animation shows how the “rotating” magnetic…

DC Motor Speed Control

Textbook

DC electric motors generate torque by a reaction between two magnetic…

On/off Electric Motor Control Circuits

Textbook

An electric motor is often used as a discrete control element in a…

Understanding How Three-phase Electric Motors Work

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The key to understanding how three-phase electric motors work is to…

VSD and VFD Motor Drive Features

Textbook

Modern DC and AC motor drives provide features useful when using…

Controller Output Current Loops

Textbook

The simplest form of 4-20 mA current loop is the type used to…

Introduction to Capacitors and Capacitance

Textbook

Any two electrical conductors separated by an insulating medium…

Understanding Area, Volume and Common Geometry

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Area refers to the size of two-dimensional surface. Volume refers to…

Proximity Switches

Textbook

A proximity switch is one detecting the proximity (closeness) of some…

Comparison of Op-Amp Circuits With Analogous Pneumatic Mechanisms

Textbook

Self-balancing pneumatic instrument mechanisms are very similar to…

Fluid Mechanics

Textbook

A fluid is any substance having the ability to flow: to freely change…

Numerical Differentiation

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As we have seen, the concept of differentiation is finding the…

Ethernet networks: Repeaters, Cabling and Switching Hubs

Textbook

An engineer named Bob Metcalfe conceived the idea of Ethernet in 1973,…

Non-contact Temperature Sensors

Textbook

Virtually any mass above absolute zero temperature emits…

Level Sensor Accessories

Textbook

Disturbances in the liquid tend to complicate liquid level…

Difference Between Calibration and Re-ranging

Textbook

To calibrate an instrument means to check and adjust (if necessary)…

Derivative (Rate) Control

Textbook

The final element of PID control is the “D” term, which…

Ions in Liquid Solutions

Textbook

Many liquid substances undergo a process whereby their constituent…

Differential Pressure Transmitters

Textbook

One of the most common, and most useful, pressure measuring…

Pressure Switches

Textbook

A pressure switch is one detecting the presence of fluid pressure.…

Laser Spectroscopy

Textbook

A laser is a light source emitting waves of light that not only…

ANSI/IEEE Function Number Codes

Textbook

In the United States, the ANSI and IEEE organizations have…

Valve Seat Leakage

Textbook

In some process applications, it is important that the control valve…

Pressure Sensor Accessories

Textbook

Multiple accessories exist for pressure-sensing devices to function…

Calibration Errors and Testing

Textbook

The efficient identification and correction of instrument calibration…

Filled-bulb Temperature Sensors

Textbook

Filled-bulb systems exploit the principle of fluid expansion to…

Solenoid Valves

Textbook

A very common form of on/off valve used for pneumatic and hydraulic…

4 to 20 mA Analog Current Signals

Textbook

The most popular form of signal transmission used in modern industrial…

Proportional-only Control

Textbook

Imagine a liquid-level control system for a vessel, where the position…

Displacement and Displacer Level Instrumentation

Textbook

Displacer level instruments exploit Archimedes’ Principle to…

Process/Instrument Suitability

Textbook

Every flow-measuring instrument exploits a physical principle to…

Understanding Electrical Power Grids

Textbook

The term “grid” refers to the conductors and equipment…

Fluorescence Measurement

Textbook

When a high-energy photon strikes an atom, it may eject one of the…

The s Variable: Euler’s Relation and Phasor Expressions of Waveforms

Textbook

A powerful mathematical concept useful for analyzing practically any…

Periodic Table of the Ions

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EIA/TIA-232, 422, and 485 Networks

Textbook

Some of the simplest types of digital communication networks found in…

Control Valve Sizing

Textbook

When control valves operate between fully open and fully shut, they…

LRV and URV Settings, Digital Trim (Digital Transmitters)

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The advent of “smart” field instruments containing…

Positive Displacement Flowmeters

Textbook

A positive displacement flowmeter is a cyclic mechanism built to pass…

Overpressure Protection Devices

Textbook

Fluid pressure exerts force on any surface area it contacts, as…

Quantitative PID Tuning Procedures

Textbook

A quantitative PID tuning procedure is a step-by-step approach leading…

What is Electrical Power?

Textbook

Since we often use electricity to convey energy from one location to…

Examples of PLC Systems

Textbook

Programmable logic controllers are essentially nothing more than…

Physics and Chemistry Terminology and Definitions

Textbook

Atom: the smallest unit of matter that may be isolated by chemical…

Vibration Monitoring Hardware

Textbook

The following photograph shows a large air blower in a wastewater…

On/off Electric Motor Control Circuits

Textbook

An electric motor is often used as a discrete control element in a…