Category: Mechatronics, Industrial Control & Instrumentation
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DC Motor Power Op-amp Speed Controller
Let’s consider the functional diagram below: Figure 1 DC motor power op-amp speed controller functional diagram The D/A converter outputs a voltage directly related to the potentiometer position. However, the D/A converter’s output current is limited and not enough to … Read more
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Basic Features of Power Semiconductor Controlled Drives
Power electronics deals with the applications of solid state electronics for the control and conversion of electric power. The conversion systems require switching power semiconductor devices on and off. The key components of an electric drive controlled by a power … Read more
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How to calibrate a dc voltmeter
An instrument may be calibrated by comparing its reading with that of a more accurate instrument when both are measuring the same quantity. The more accurate instrument is used as a standard for comparison purposes. The figure below illustrates the … Read more
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How to calibrate a dc ammeter
The figure below shows two dc ammeters connected in series, so that they are both measuring the same current. Figure: DC Ammeter Calibration An ammeter may be calibrated by comparing it to a more accurate (standard) ammeter measuring the same … Read more
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What are PLC-Based Water Treatment Plants?
Most of the water treatment plants in the previous decade were manually operated. However, they were automated to a certain degree using relays or electrical control panels but the system was not reliable and required a lot of space. In … Read more
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Toggle Switches
Toggle switches are available in various contact configurations. Each switch consists of one or more poles, where each pole is actually a separate switch. The switch contact configurations include: Single-pole/single-throw switch (SPST) This is the simplest switch. It has a … Read more
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Electric Solenoid Actuator – Features & Operation
A typical electric solenoid actuator consists of a coil, armature, spring, and stem. This is illustrated in the figure below: Figure: Electric solenoid actuator The coil is connected to an external current supply. The spring rests on the armature to … Read more
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Pressure Control Valve Operation
A pressure control valve is a spring-loaded valve that is capable of maintaining a constant pressure in a system regardless of the flow rate. This is important, since most pumps e.g. gear pumps are constant-displacement types – a constant volume … Read more
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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: Figure: Vortex shedding flowmeter In flow measurement the vortex shedding frequency is usually a … Read more
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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 … Read more