The role of the intermediate relay - Solutions - Huaqiang Electronic Network

Photocoupler

The intermediate relay is a relay. Its principle is the same as that of the AC contactor. It consists of a fixed iron core, a moving iron core, a spring, a moving contact, a static contact, a coil, a terminal block and an outer casing. When the coil is energized, the moving iron core moves under the action of electromagnetic force, and the moving contact is actuated to make the normally closed contact separate, and the normally open contact is closed; when the coil is powered off, the moving iron core drives the moving contact under the action of the spring. Reset.

1. Replacing the small contactor intermediate relay contacts have a certain load capacity. When the load capacity is small, it can be used to replace small contactors, such as electric shutters and some small appliances. This has the advantage that it can not only serve the purpose of control, but also save space and make the control part of the appliance more delicate.
2. Increasing the number of contacts This is the most common use of intermediate relays. For example, in a circuit control system, the contacts of one contactor need to control multiple contactors or other components, but instead add an intermediate relay to the line.
3. Increasing the contact capacity We know that the relay capacity of the intermediate relay is not very large, but it also has a certain load capacity, and the current required for its driving is small, so the intermediate relay can be used to expand the contact capacity. For example, it is generally not possible to directly use the output of the inductive switch or the triode to control the electrical components with relatively large loads. Instead, an intermediate relay is used in the control line, and other loads are controlled by the intermediate relay to achieve the purpose of expanding the control capacity.
4. Switching contact type In industrial control lines, such a situation often occurs. The control requires the use of the normally closed contact of the contactor to achieve the control purpose, but the normally closed contact of the contactor itself has been used up and the control task cannot be completed. At this time, an intermediate relay can be connected in parallel with the original contactor coil, and the normally closed contact of the intermediate relay can be used to control the corresponding components, and the type of the contact is switched to achieve the required control purpose.
5. Used as a switch In some control lines, the switching of some electrical components often uses an intermediate relay, which is controlled by the opening and closing of its contacts. For example, the automatic degaussing circuit commonly used in color TVs or displays, the triode controls the on and off of the intermediate relays, thereby The function of controlling the on/off of the degaussing coil is achieved.
6. Conversion voltage
7. Eliminate interference in the circuit