Relay News

In the power control relay the return spring and the contact spring are made of circular or sheet-like elastic materials (such as spring steel wire, tin bronze, phosphor bronze, brass, German silver, silver magnesium nickel, etc.). When it is mechanically deformed, it has a certain elasticity. We all have this feeling in practice, the greater the deformation of these springs, the greater the elastic force it produces: the smaller the deformation, the smaller the elastic force; no deformation, that is, the spring is in a free state, and no elastic force is generated. Further experiments and theoretical analysis show that: within a certain range, the size of the elastic force (F) is proportional to the size of the deformation (X). Mathematically expressed as: F=CX

We know that in a power control relay with contacts, the main task of the contacts is to "open" and "close" the circuit, so there are only two forms of movement: "divide" and "close". This "opening and closing" movement of the contact system is mainly based on the combined action of the force generated by the return spring (or reed) and the mechanical force transformed by the external input signal (this is the force in two opposite directions). Completed. That is to say, only when the input signal is small enough that the mechanical force converted by it is smaller than the force of the return spring,

Are these hazards of contact resistance manifested in any case? no, it isn't. Because the occurrence of this hazard is closely related to the circuit parameters closed by the contact. Different circuit parameters lead to different properties and hazards of contact resistance. For example, when the contact is used to close the circuit with high voltage and current (such as high-power power relay, contactor, etc.)

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

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