Tag: Industrial control
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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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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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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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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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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…
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6 Types of Machine Guards
What is Machine Guarding? Most machines have cutting blades or rotating/moving parts that can cause bodily harm if they come in contact with plant workers operating the equipment or working nearby. To protect workers from hazards related to machinery, machine guards are used. Machine guarding is a safety mechanism that typically comprises of a shield…
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Single-Phase & Three-Phase Inverters: Function and Operation
What is the Purpose of Inverters? Whereas dc machines are controlled by varying the voltage and current, ac machines are often controlled by varying the voltage and frequency. One way of accomplishing this is by using inverters. The process of converting ac from dc is referred to as inversion. Some of the reasons why ac…
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Insulated Gate Bipolar Transistor (IGBT) – Structure, Operation & Applications
IGBT is a voltage controlled device. It has high input impedance like a MOSFET and low on-state conduction losses like a BJT. In other words, this power device combines the voltage control of the MOSFET gate with the superior conduction characteristics of the bipolar device. Nonetheless, the IGBT utilizes injected-charge modulation in the base region…
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Telemetry in Instrumentation Systems
Telemetry can be defined as the science of gathering information at some remote location and transmitting the data to a convenient location to be examined and recorded. Importance of Telemetry Within instrumentation there is usually a requirement for telemetry in order to transmit data or information between two geographical locations. The transmission may be needed…
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Optothyristors: Features & Principle of Operation
Silicon Controlled Rectifiers (SCRs), Triacs and other solid-state devices used for switching larger voltages and currents ON and OFF are referred to as thyristors. Thyristors control switching in an ON-OFF way, in the same way to a light switch which is different from a transistor that can vary the amount of current in its emitter-collector…