Relay News

When the dynamic and static contacts of the power relay work in the closed state, a certain pressure (contact pressure) is always applied to make them close contact with each other, so as to reliably connect the circuit and conduct the current. It is always hoped that the stronger the current conducting ability, the better. It is best to be like a whole piece of metal with the same shape and size.

For a contact power relay, the contact is its actuator, which is the part it uses to tear and connect the circuit: the reliability and life of the power relay's work depend to a large extent on the quality of the contact's work. Therefore, we must pay full attention to this problem in order to correctly design and use it to provide the most reliable automatic devices for national economy and national defense construction.

Since the power relay plays a very important role in the automation system, its quality, technical performance and economic indicators must be related to the speed of economic construction and the safety of workers, so it must be put forward some basic. requirements.

Between the induction and execution of power relays and other switching appliances, they are opposed to each other and struggle with each other. This is because for the induction part of an electrical appliance, it is always hoped that its ability to respond to signals is as strong as possible

As can be seen from the various examples mentioned above, any power relay, regardless of its operating principle, structural type, and application situation, is a certain signal (electrical or non-electrical) input according to the outside world. An appliance that controls the "on" and "off" of current in a circuit. This is its commonality. This commonality shows that in order to complete its specific mission, any power relay should have a corresponding induction mechanism that can respond to a certain input signal from the outside world, and an executive function that realizes "on and off" control of the controlled circuit. Corresponding actuator. Since the action of the power relay's actuator requires a certain physical quantity, and the external input signal has two types of electricity and non-electricity, the induction mechanism of the power relay should first have an induction function as follows: Convert the input electricity or non-electricity into a certain specific physical quantity suitable for the action of the actuator.

In addition, photoelectric, piezoelectric, electrostatic induction, chemical reaction and other principles can be used to make various relays that can respond to other non-electrical quantities, such as photoelectric relays, speed relays, pressure relays, etc. With the rise of electronic technology, a new way has been opened up for the development of the above-mentioned various relays. In recent years, various contactless relays and other semiconductor electrical appliances composed of transistors have been increasing. They are used in conjunction with relays with contacts to learn from each other's strengths and make up for their shortcomings. direction.

A reed power relay composed of a coil and a reed tube is also a special electromagnetic power relay, as shown in Figure 1-7. When the coil is energized, the reed, which is made of magnetic conductive material and acts as a contact, is magnetized, and its free ends form a north pole (N) and a south pole (S) to attract each other, so that the controlled circuit is connected. After the coil is powered off, the reeds are separated under the action of their own elastic force, and the circuit is cut off, so the same control function of the above-mentioned general electromagnetic power relay can also be achieved by using it. Because it has the advantages of high sensitivity, fast action speed, very simple structure, small volume, and long life due to the contact point being sealed in the protective gas, it is more and more widely used in various automatic control systems.

If a short-circuit copper sleeve (or short-circuit coil) is placed between the coil and the iron core of the electromagnetic voltage power relay, the armature can not be pulled in or released immediately after the coil receives a signal or the signal disappears, and it takes a certain period of time. action. This kind of power relay is called electromagnetic time power relay, and its structure principle and symbol are shown in Figure 1-6a and b. This kind of component is essential in situations where delayed action or work in a certain time sequence is required. For example, in Figure 1-4, although the power supply voltage exceeds the user's specified value, it can return to normal in a very short time. At this time, it is not necessary to cut off the circuit to ensure the normal use of electricity by the user. For this purpose, a time power relay can be used to control, as shown in Figure 1-6c.

From here, we can clearly see that because the electromagnetic power relay adopts such a working principle and structure, when it controls the production process in a certain way, it can realize the control that is difficult to achieve by manually switching electrical appliances (such as knife switches). function to meet more and more complex control requirements put forward in the production process. E.g

From here, we can clearly see that because the electromagnetic power relay adopts such a working principle and structure, when it controls the production process in a certain way, it can realize the control that is difficult to achieve by manually switching electrical appliances (such as knife switches). function to meet more and more complex control requirements put forward in the production process. E.g

The phenomenon has created various relays with different structures and functions, and has made great contributions in the struggle of mankind to conquer nature. A long time ago, people made electromagnetic relays based on the phenomenon of electromagnetic induction to meet the needs of communication

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.