Author: John Mulindi
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Impeller Flowmeters: Features, Installation Considerations & Uses
Impeller flowmeters at times referred to as paddlewheel meters are one of the frequently utilized flowmeters for industrial flow measurement applications. Impeller flowmeters are cost effective compared to turbine meters and can be used in applications that are challenging to handle with other types of flow metering instruments. They are related to turbine meters in…
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The Effects of Low Power Factor on Electrical Equipment
The cosine of the angle between voltage and current in an AC circuit is referred to as the power factor. In a typical AC circuit, there is a phase difference Φ between the voltage and current. The term cos Φ is termed to as the power factor of the circuit; if the current is inductive,…
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Fundamental Communication & Networking Terminology
To be able to choose the right network technology, it is essential to understand some key terminology so that the features and capabilities of various networks and technologies can be categorized and compared. Some of the basic communication and networking terminology includes: Station A station represents a single communication element on a network system. Each…
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Synchronous Compensators, What is their Purpose in Power Systems?
When designing a transmission or distribution system, the engineer must take into account not only the power requirement of the loads, but also the fact that they consume reactive power and to the same degree key, that networks include inductive and capacitive components which themselves absorb or generate reactive power. Power is generated and consumed…
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What is the Function of Unified Power Flow Controller?
In a number of cases, it may be possible to increase the grid’s capacity through enhanced control of the active and reactive power flow in the transmission network independently of busbar voltage. The Unified Power Flow Controller (UPFC) provides the reactive shunt compensation, active and reactive series compensation and phase shifting. It is thus capable…
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Absolute vs. Secondary Instruments
Measuring instruments may be classified as either absolute instruments or secondary instruments. Absolute Instruments This type of instruments gives the value of the measurand in terms of instrument constant and its deflection; this instrument type doesn’t require comparison with any other standard. For instance, the tangent galvanometer gives the value of the current to be…
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How to Measure Pressure using a U-tube Manometer
There are three categories of pressure measurement, namely absolute pressure, gauge pressure and differential pressure. The absolute pressure is the differences between the pressure at a particular point in a fluid and the absolute zero of pressure, that is, a complete vacuum. When the pressure measuring device measures the difference between the unknown pressure and…
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Basic Features of Numerical Control
Numerical control is a form of digital control that is employed on machine tools such as milling machines and lathes to automatically cut and shape the work-piece without a human operator. Each machine has its own set of axes or parameters that must be controlled; case in point is a milling machine as illustrated in…
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How to Size a Control Valve
Control valve sizing refers to the procedure determining the correct size of a valve body. A valve sizing equation for incompressible fluids is given by: Which is the same as: Where Cv is the valve flow coefficient/valve capacity P1 = Upstream fluid pressure P2 = Downstream fluid pressure ρ = Mass density of fluid Q…
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Process Control System Design for a Distillation Unit
The aim of a typical control system is to force a given set of process variables to act in some desired and prescribed way by either fulfilling some requirements of the time or frequency domain or achieving the best performances as expressed by an optimization index. The scope of the control tasks varies widely. The…