Finder intermediate relay: used in relay protection and automatic control systems to increase the number and capacity of contacts, which are used to transmit intermediate signals in control circuits. The traditional finder intermediate relay and contactor essentially use the basic principle of electromagnet to realize the isolation and amplification control of small current to large current. There is no difference in principle between relay and contactor. The function and wiring method of finder intermediate relay are explained in detail below.
Function of finder intermediate relay
The working principle of finder intermediate relay is the same as that of AC contactor, which is composed of fixed iron core, moving iron core, spring, moving contact, static contact, coil, wiring terminal and shell. When the coil is energized, the moving iron core moves and closes under the action of electromagnetic force, and the moving contact moves to separate the normally closed contact and close the normally open contact; When the coil is powered off, the moving iron core will bring the moving contact to reset under the action of the spring.
In the control circuit of modern industry or household appliances, finder intermediate relay is often widely used. For different control circuits, their functions will be different. What is the function of finder intermediate relay? In fact, the common functions in the line can be divided into the following situations:
1. Finder intermediate relay can replace small contactor
The contact of finder intermediate relay has certain load capacity, which can be used instead of small contactor when the load capacity is very small. Especially in the control of electric rolling gate and small household appliances, it not only plays a control role, but also has certain advantages in saving installation space. At the same time, the control part of the electric appliance can be relatively refined.
2. Finder intermediate relay can increase the number of contacts
It is believed that this practice is also quite common in circuit control, especially when there is only one contactor, how to control multiple contactors or other components? In order to solve this problem, a finder intermediate relay is added on the line.
3. Finder intermediate relay can increase contact capacity
You should know that although the contact capacity of finder intermediate relay is not particularly large in general, it has a certain load capacity, and the current required for driving is very small. For example, when the output of induction switch or triode cannot be directly used to control electrical components with relatively large load, we can use finder intermediate relay as a medium to expand the contact capacity.
4. Finder intermediate relay can change contact type
These situations often occur in industrial control circuits. In the control process, the normally closed contact of the contactor is required to achieve the control purpose, because the normally closed contact equipped with the contactor itself has been used up, and the control work cannot be completed. At this time, the finder intermediate relay can be connected in parallel with the original contactor coil. The principle is to let the normally closed contact of the finder intermediate relay control the corresponding components to realize the type of switching contact, so that the control task requirements can be successfully completed.
5. Finder intermediate relay can be used as a switch
You should know that in some control circuits, the on and off actions of electrical components need to be completed through a finder intermediate relay, that is, the control is realized by the on and off of its contacts. Examples include the automatic degaussing circuit commonly used in color TVs and displays, in which the triode controls the on-off of the finder intermediate relay to control the on-off of the degaussing coil.
6. Finder intermediate relay can convert voltage and remove circuit interference
Although there are many protective and anti-interference measures in industrial control and computer control circuits, this interference phenomenon still exists more or less.