Author: John Mulindi
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Techniques used in Stopping DC Motors
Stopping of a motor is actually a form of speed control. Methods used to stop DC motors are in a way similar to speed control techniques. To stop a motor, you must accelerate in the direction opposite to that in which it is moving. There are two techniques of electrically stopping a DC motor, namely:…
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Microwave Spectroscopy: Features, Types & Applications
Microwave Spectroscopy The section of the electromagnetic spectrum extending approximately from 1 mm (300,000 MHz) to 30 cm (1000 MHz) is referred to as the microwave region. Spectroscopic applications of microwaves consist of almost exclusively of absorption work in gaseous samples. With some exceptions, the various types of spectra are distinguished by their energy origins.…
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Vision Sensors: Features, Concepts & Applications in Manufacturing
Vision Sensors A vision sensor is basically a TV camera connected to a computer, usually a PC. Special vision software analyzes the video image and makes specific recommendation to the work area. Vision systems require computing power to process thousands of pixels of information continuously in order to arrive at a go/no-go decision about what…
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Steam Sampling for Conductivity: Instrumentation Structure
Sampling Systems The Purpose of Sampling Systems The objective of a sampling system is to obtain a truly sample of the solid, liquid or gas to be analyzed, at an adequate and steady rate, and transport it without change to the analysis instrument, while ensuring that all the necessary precautions are taken to make this…
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How Cascade Control System Enhances Dynamic Response to Load Changes
The major limitation of a conventional feedback control system is that the correction for disturbances does not start until the process output deviates from the setpoint. Feedforward control provides big improvements in processes with large time constraints or time delays. But, feedforward control requires that the disturbances be measured explicitly and a model must be…
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Cable Screens: Types & Connections
Electromagnetic Compatibility (EMC) is one of the key factors of consideration in the design, construction, manufacture and installation of electrical and electronic equipment and systems. Electrical equipment must be designed not only to meet a functional technical performance specification but due consideration must also be given to the interaction the equipment has with the electromagnetic…
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AC to AC Power Converters with Intermediate DC Link: Types, Features & Applications
This category of AC drives that is often referred to as “Variable Frequency Inverters” is one of the most extensively used drives in industrial motor control applications. Generally, the concept of these inverter drives can be summarized into three parts: We have two main classifications of these AC drives that are based on the aforementioned…
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Instrumentation Systems Installation: Precautions to Take
Analog systems are normally based on low voltages and as a result, they are vulnerable to electrical noise. In most plants, a PLC may be controlling 415 V high power motors at 100 A, and at the same time, reading thermocouple signals of a few mA. Great care must therefore be taken to avoid interference…
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Vacuum Circuit Breakers: Features, Operation & Applications
In vacuum circuit breakers, vacuum typically at pressures ranging from 10-9 to 10-6 bar is used as the quenching medium. At such pressures, high dielectric strength can be achieved. The contact separation needed at such low pressures is only 0-20 mm and low energy mechanisms may be employed to operate the contacts through expendables bellows.…
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DC to DC Power Converters: Function, Types, Operation & Applications
DC to DC power converters also referred to as choppers provide the means to change one DC voltage to another. Normally the conversion is to a lower voltage however, we also have step-up converters. DC to DC power converters are fed from a DC supply usually comprising an uncontrolled AC to DC converter or alternatively…