Author: John Mulindi
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The Principle of Operation of a Vortex Flowmeter
If a bluff (non-streamlined) body is placed in a flow, vortices detach themselves at regular intervals from the downstream side as illustrated in the diagram below: In flow measurement the vortex shedding frequency is usually a few hundred hertz (Hz). At Reynolds numbers over 103 the volumetric flowrate, Q, is directly proportional to the observed…
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Basic Steps to Consider in Designing a Control System
Typically a control system should be designed to work together with an already existing process. The control design problem can be stated at local, supervisory or even plant-wide level. If we consider the local level, the typical steps in designing the control are: Most of these activities should be performed iteratively. For example, if the…
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Fuzzy Controller and its Industrial Applications
Fuzzy logic is a human model, potentially applicable to a wide range of processes and tasks that require human instinct and experience. In computer, truth-values are either 1 or 0, which corresponds to true/false duality. In fuzzy logic, truth is the matter of degree, hence truth-values ranges between 1 and 0 in a continuous manner.…
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The Principle of an Optical Pyrometer Temperature Sensor
A heated object emits electromagnetic radiation. At temperatures below approximately 400 °C this radiation can be felt as heat. As the temperature rises, the object starts to emit visible radiation passing from red through yellow to white. Intuitively we can use this radiation to qualitatively measure temperature as illustrated in the table below: Temperature Colour…
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Data Acquisition and Telemetering in Power Systems
To be able to manage and control a power system, the network engineer requires reliable and current information about the state of the network. He obtains this information from power flows, bus voltages, frequency and load levels along with the position of circuit breakers and isolators, the source of these data being in the power…
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AC vs DC Power & Motors – Differences and Benefits
AC and DC power isn’t new and yet it has been two main types of power we are taking advantage of even in the modern age we live in. But did you ever understand the difference between AC and DC power, did you know how we use it, and what is the preferred power type…
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What is the difference between a Power transformer and a Distribution Transformer?
Introduction The transformer, in simple terms can be defined as the voltage regulator. It helps in stepping up and stepping down of the voltages. We all have seen transformers in our locality, where the current is passed from higher voltage to the lower voltages. In this blog, we will discuss about the differences between the…
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Supervisory Control and Data Acquisition in Power Systems
The term supervisory control and data acquisition (SCADA) refers to the network of computer processors that provide control and monitoring of remote electrical or mechanical operation e.g. management of power distribution grid or the control of mechanical processes in a manufacturing plant. Typical the old SCADA systems would encompass computers and network links that manage…
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The Principle of Operation of Optical Encoders
An encoder is a device that provides a digital output as a result of an angular or linear displacement. The position encoders can be grouped into two categories: Incremental Encoders Let’s consider the basic form of an incremental encoder for the measurement of angular displacement of shaft shown below: The incremental encoder shown above consists…
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Transfer Functions and Block Diagrams of Control Systems
Transfer Functions A transfer function is a mathematical formulation that relates the output variable of a device to the input variable. For linear devices, the transfer function is independent of the input quantity and solely dependent on the parameters of the device together with any operations of time, such as differentiation and integration that it…