Thermocouples, of T.C. for short, is a device that is used to convert heat into electricity. It can also work reversely by converting electric current into heat.
How do Thermocouples Work?
There are 2 wires made of dissimilar metals connected at one end to form a junction. When the said junction is heated, electricity will flow through the wire. Heated electrons will begin to cross the junction on their own. The electrons will lose potential energy and gain kinetic energy because of the properties of the different metals. Thermocouple creates a very small voltage but many thermocouples can be combined together in order to produce a larger voltage. This is also known as thermopile.
Thermocouples do not only produce electricity from heat; they can also produce heat from electricity, and even cold from electricity like a refrigerator. When 2 dissimilar wires are connected at both ends, some voltage source will make current flow through the loop and this will lead to one junction getting hot and the other becoming cold. The electrons gain kinetic energy as they cross the hot junction. This is why the metal is hot. On the other hand, the electrons lose kinetic energy as they cross the cold junction and this is what makes the junction cold.
It is indeed not easy to measure the accurate voltage that a thermocouple produces when heat is applied to the junctions, because the voltmeter wires that are connected to the thermocouple is definitely made of a different metal than the thermocouple’s wires. This means the connection between a voltmeter and thermocouple is another thermocouple itself.
Uses of Thermocouples
One of the most popular examples for the use of thermocouples is gas heaters with pilot flames. The thermocouples are stacked in order to form a thermopile so that it can generate sufficient voltage from the heat of the pilot flame to keep the gas valve open so that it can supply gas to the pilot flame. Once the gas runs out, the flame will extinguish and the voltage across the thermopile decreases tremendously, which brings about the closing of the electric gas valve. Other ways in which thermocouples are used are CPUs, as well as to monitor temperatures in freezers and air conditioners.
Frequency inverters, or frequency converters, are a power control conversion device that is commonly used to control electric motors in wide ranges of speed operations. Frequency inverters change the frequency supply to the motor stator windings to achieve variable speed control purposes. Frequency inverters consist mainly of a rectifier (to change AC to DC), an inverter (to change DC to AC), drive unit, braking unit, filter and many more. The main circuit is controlled by the control circuit; AC power is changed into DC power by the rectifier, the rectifier circuit output is smoothened out by the DC intermediate circuit and then the DC power is converted by the inverter circuit into AC power again.
Frequency Inverter Troubleshooting
Frequency inverters are powerful tools in maintaining processes to solve frequency inverter performance issues using diagnostics and trouble shoot other related processes at the same time. By understanding how frequency inverters interact with the whole process, you can improve the overall production and quality of the product. The misapplication of the frequency inverter can cause many faults such as power issues, variation in the speed, the utility’s capacity switching and other mistakes which can bring about the failure of the frequency inverter. Make sure to evaluate the consistency as well as the condition of the processes when trying to determine the factors of the failure.
Frequency Inverter Basic Theory
When you understand the requirements of the load, applying a frequency inverter to a specific application is not a tough job. The frequency inverter should have good current capabilities for the motor so that it can produce the required torque for the load. Machine torque is typically independent of the speed of motor. You must constantly keep in mind that the load horsepower increases linearly with rpm.
Frequency Inverter Saves Energy Efficiently
Frequency inverters are one of the most successful equipment used by strategy managers to control the usage of electrical energy and minimize cost of utility. Energy use can reduce up to 50% when frequency inverters are incorporated into applications like pumps, fans and cooling towers by matching the speed of motor to the changing load requirements.