Relays and Production Process Automation

Everyone is very familiar with the "switch", and we often use it in our daily life. For example, electric lights, radios, and electric fans are equipped with various "pull switches", "button switches", "toggle switches", etc. They are operated several times by us almost every day. The role of these switches is also very clear to everyone. The so-called switch is the "on", "off" circuit! You turn the switch "on," and the circuit it controls is "connected" to the power source, the light turns on, and the fan turns. When you turn the switch "off" again, the circuit is cut off, the lights go out, and the fans stop. However, many power consumption problems in actual production and even daily life are often much more complicated. For example, the start and stop of a motor can be controlled by a knife switch. But for a large gantry planer or a rolling mill, in order to complete the complex work process, more than ten, dozens or even hundreds of motors are required. It is practically impossible for so many motors to be controlled by knife switches and directly controlled by humans. To this end, a "switch" that does not require direct operation by humans, but can automatically switch circuits according to various signals reflected in the production process, is required to make up for the above-mentioned shortage of manual switches. Such switches are called "automatic operation switches" or "automatic appliances". There are many types of automatic appliances. For example, in the power system, there are high-voltage air circuit breakers, oil circuit breakers, isolating switches, and various relays used for system protection, which are used to switch high-voltage lines; in industrial and mining enterprises, there are low-voltage automatic circuit breakers used to control various circuits and electrical equipment. Air circuit breakers (also known as automatic switches), contactors, relays, etc. It can be said that any place where electricity is generated and used is inseparable from electrical appliances of various types and functions. In particular, relays are widely used in industrial and mining enterprises, transportation, farmland water conservancy, national defense, and space technology as basic automation components for automation, telecontrol, remote control, and telemetry.

You may feel a little unfamiliar when it comes to relays. In fact, its "switching" function in the circuit, or more broadly speaking, the "controlling" function, is often seen. For example, whenever the car turns a corner, an "eye" on its head, an indicator light, flickers on and off, which is the relay at work. In the control box on the head of the trolleybus, there is always a crackling sound, that is, many relays (of course there are other automatic electrical appliances in it) are busy working, controlling the speed and start and stop of the tram. You pick up the phone, dial a number, and you're immediately connected to the person you're talking to. Whose role is this? Relay! Take the fluorescent lamps we often use, where the starter is actually a relay! We also know that the most characteristic feature of modern industry is the high degree of electrification and automation of the production process. This kind of modern production can continuously improve labor productivity, improve product quality, reduce product cost, and free people from a lot of heavy manual labor. This kind of automation in production cannot be accomplished by mechanical devices alone, but must be realized with the help of various electrical automatic devices. In these automatic devices, relays and various other electrical components occupy an important position and play an active role. For example, hundreds of relays will be used in an automatic telephone exchange with a capacity of 100 doors, and thousands or even tens of thousands of relays will be used when the capacity is 1000 doors. Every time we make a call, dozens or even hundreds of relays in the switch are working to connect the objects we designate. For a large-scale gantry creation machine, dozens of relays are needed to realize the automatic advance and retreat of the workpiece at different speeds, and the automatic tool movement, advance and retraction of the tool holder. Production of highly automated workshops or factories requires only a few people to take care of raw materials and finished products, mainly by means of various automatic devices, of which relays are indispensable components. As for the fields of national defense and space technology, the application of relays is also very prominent. Whether it is tanks, warships, aircraft, or missiles, satellites and spacecraft, a certain number of relays of various types are used in their ground or air control systems. For example, there are usually as many as ten or hundreds of relays used in aircraft landing, driving, fire control, lighting and heating. It can be seen that the relay and the automation of the production process are inseparable.