What are the intermediate relays used for, respectively?

The intermediate relay is a relay, and its principle is the same as that of the AC contactor, which is composed of a fixed iron core, a moving iron core, a spring, a moving contact, a static contact, a coil, a terminal block and a shell. The coil is energized, and the moving iron core moves and engages under the action of electromagnetic force, driving the action of the moving contact, so that the normally closed contact is separated and the normally open contact is closed; The coil is de-energized, and the moving iron core drives the moving contact to reset under the action of the spring.

In the industrial control circuit and the current household appliance control circuit, there are often intermediate relays, for different control circuits, the role of intermediate relays is different, and the role of the first road is common as follows.

1.Instead of small contactors.

The contacts of the intermediate relay have a certain load capacity, and when the load capacity is relatively small, it can be used to replace the use of small contactors, such as electric roller shutters and the control of some small household appliances. The advantage of this is that it can not only play the purpose of control, but also save space, so that the control part of the electrical appliance is more exquisite.

2 Increase the number of contacts.

This is the most common use of intermediate relays, for example, when the contact of a contactor in a circuit control system needs to control multiple contactors or other components, an intermediate relay is added to the circuit.

3 Increase contact capacity.

We know that although the contact capacity of the intermediate relay is not very large, it also has a certain load capacity, and the current required for its drive is very small, so the contact capacity can be expanded with the intermediate relay. For example, it is generally not possible to directly use the output of inductive switches and transistors to control electrical components with relatively large loads. Instead, an intermediate relay is used in the control line to control other loads through the intermediate relay to achieve the purpose of expanding the control capacity.

4 Conversion contact type.

In the industrial control circuit, it often happens that the control requirement needs to use 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 contact type can be converted to achieve the required control purpose. As.

5 is used as a switch.

In some control circuits, the on/off of some electrical components often use intermediate relays to control the opening and closing of their contacts, such as automatic degaussing circuits commonly found in color TVs or displays, and the triode controls the on/off of intermediate relays, so as to control the on/off of degaussing coils.

6 Conversion voltage.

7 Eliminate interference in the circuit.

In industrial control or computer control circuits, although there are various interference suppression measures, interference phenomena still exist to a greater or lesser extent.

In addition to the main contact, the contactor generally has auxiliary contacts, the main contact controls the on/off of the main circuit load, and the auxiliary contact can realize different functions according to the actual circuit needs.

Take CJX2 series contactors as an example:

The first two frames represent the rated current of the main contacts, and the last two frames represent the number of normally open and closed contacts (1 is one pair, 2 is two pairs).

The contactor has more electric shocks, more functions, and a wider range of applications, which can save space and do not need to install too many contactors. Waste of money.

No relays are required. It can be directly connected to the contactor, normally open parallel 13,14, normally closed series 13 in front or 14 behind.

The valves and switches of the V DC voltage rely on the intermediate relay to connect the coil power supply to the upper end control output. Normally open and normally closed contacts are connected to lower valves, switches;

3. Proximity group switch - intermediate relay - solenoid valve connection Lingdian: normally open connection: 24+, proximity switch +, one way; 24-, connected proximity switch -, and relay - (14), two-way, proximity switch control line trembling slip Qi connected relay + (13), three-way, relay normally open and contactor 13,14,4-way;

4. Normally closed connection: 1, 2, 3 channels are the same as above, and the relay is normally closed in series in front of contactor 13 or behind 14, 4 ways.

No relays are required. Directly connected to the contactor.

On it, normally open parallel 13,14, normally closed series 13 front or 14 behind.

V DC voltage valves and switches are intermediate relays that rely on trembling.

Connect the coil power supply to the upper control output. Normally open and normally closed contacts are connected to lower valves, switches;

3. Proximity switch.

Intermediate relay - solenoid valve connection: normally open eggplant connection method: 24+, proximity switch +, one way; 24-, connected proximity switch -, and relay - (14), two-way, proximity switch control line connected relay + (13), three-way, relay normally open and contactor 13,14,4-way;

4. Normally closed connection method group: 1, 2, 3 channels are the same as above, and the relay normally closed series is connected in front of the contactor 13 or behind 14, 4 ways.