Relay designation: principle of operation, types and manufacturers

2024 Author: Howard Calhoun | [email protected]. Last modified: 2023-12-17 10:16

The designation of the relay on the diagrams or in letter form is necessary so that qualified specialists can easily find it. As already mentioned, in the case of a letter designation, K is used. However, it is fair to say here that there are such drawings as electrical principal or simply electrical drawings that do not use letter names. In this case, the symbol of the relay in graphical form is used. Then the relay will be described as a rectangle, from the large sides of which one contact departs.

What is rel

A relay is a switching device, or simply a KU. The main purpose of this item is to connect or disconnect the circuit of an electrical or electronic circuit in the event that the input current values \u200b\u200bare changing in a certain way. As for the scope of use, for the first time this device as a working unit was used in the telegraph. The use in electronic and electrical circuits came much later.

Equipment Arrangement

It is worth saying that the designation of the relay in the letter K is used quite rarely, since today there are many different types of this device, and they have a different designation. However, the initial device of these devices is approximately the same.

A relay is a coil that has a non-magnetic base. A copper wire with fabric or synthetic insulation is wound on this base. However, the most commonly used dielectric varnish coating. Inside the coil, which stands on a non-conductive base, a metal core is placed. In addition, there are parts such as springs, armature, contacts and connectors.

If the letter designation of the relay is only one letter K, then the principle of operation of this device is as follows. When current is applied to the solenoid winding, the core will begin to attract the armature. Since the elements are metal, when they are connected, the circuit will close. If the current strength begins to weaken, then at a certain level the force of the spring will become greater, due to which it will push the armature back and the circuit will open. By itself, the relay will work quite sharply. To increase the smoothness and accuracy of operation, resistors are usually added to the circuit, and capacitors are used to protect the device from any surges.

In short, the designation of the relay with the letter K means that this is the simplest equipment that works on the principle of the simplest electromagnetic induction. Due enoughsimple way of working, it is considered very reliable.

Relay specifications

This device has several main characteristics that you should pay attention to.

1. Such a parameter as sensitivity is very important. It will determine how much current is needed to make the relay work.
2. There is such a characteristic as the resistance of the electromagnet winding.
3. Each device has its own threshold for switching on and off the circuit. In other words, each relay has its own minimum current for tripping and tripping.
4. There is such a characteristic as the time of attraction and the time of repulsion of the anchor.

Relay electromagnetic type

One of the most common varieties is an electromagnetic relay. This KU belongs to the electromechanical type, and the principle of operation is based on the fact that the magnetic field that is created in the static type winding interacts with the armature. Such devices, in turn, are divided into two types. The first is electromagnetic, which respond only to the magnitude of the incoming current. The second is polarized, for which both the incoming current and its polarity are important. As for the letter designation of the relay, the letter K can still be left here. If we talk about the application, then most often they are used in control circuits. In industry, such devices are in an intermediate position between high-current devices and low-current devices.

KU with AC currenttype

As you can see from the name, this type of relay is activated when AC is applied to the input terminals. As for the designation of the voltage relay, it is often referred to as KV. This marking is applicable to almost all types, since almost all of them work with input current and its voltage.

As for the AC KU, this is a device that has control of the phase transition through zero or without it. The equipment is an integral assembly of such modules as a thyristor block, a rectifier diode block and control circuits. It is also worth noting that they can be of two types, differing in the modular base on which they are made. There may be types with transformer or optical isolation. As for the application, then, of course, they are used in variable networks with a maximum voltage of 1.6 kW. As for the current, its value should not exceed 320 A.

Separately, it is worth mentioning devices that are designed for 220 V networks, since they cannot function without such devices. Such devices are used if there is a need to close or open contacts of a multidirectional type. An example is a device that illuminates the area and has a motion sensor. Then it turns out that one of the inputs is connected to power, and the other to the sensor.

KU with direct current

In addition to such devices, such as time relays are also used, the designation of which is KT.

DC switching device can bepolarized or neutral type. The difference is that polarized devices are sensitive to the polarity of the input voltage. Depending on these poles, the KU anchor can change its direction of movement. Neutral ones do not depend on this parameter. Most often, such devices are used only if it is not possible to connect to an alternating current network.

This is due to the fact that the cost of such devices is higher than with alternating current, as well as the need to connect a power supply for normal operation.

Electronic type device

In addition to current devices, there are also electronic or thermal types. For example, the designation of the thermal relay KK. The scope of its application is also quite clear, as the name implies. Pay more attention to electronic devices.

As for the design and principle of operation, they are not too different from electromechanical. The essential difference lies in the fact that in this case a semiconductor type diode is used to perform all the necessary functions. The most common use of such devices is in vehicles, where most of the functions are performed using electronic relay control units. It is not yet possible to completely abandon their use.

Device manufacturers

Today, there are many companies that produce such products, but you should pay attention only tosome of them.

For example, among European manufacturers, the third place is occupied by a German company called Finder. It is engaged in the production of such devices as general purpose relays, solid state, power, time relays. There is also a pressure switch, the designation of which is KP.

If we talk about domestic producers, we can single out JSC NPK Severnaya Zarya. This company is engaged in the production of anchor electromagnetic models of the switching type. The main purpose is the industrial and special areas of industry. As for the designation of the relay, in this case it is K, since they belong to a common type.

There are manufacturers from Japan. The company is called Omran and is engaged in the production of devices such as solid-state and electromechanical types of relays. In addition, they also produce products such as low-voltage switching devices.

Leading lines have been held for a long time by products from the American company American Zettler. The company is engaged in the production of about 40 different types of CU, which are suitable for a variety of purposes.