Everyone who is engaged in the role of electricity knows,Finder intermediate relayIt is widely used in electric drive. Generally, finder intermediate relays are divided into two categories:
(1) It is used to use large finder intermediate relay in parallel with AC contactor.
(2) A small finder intermediate relay used to control the transmission signal of the loop.
Finder intermediate relay has two basic functions in practical application:
1. Contact extension is generally used for the main circuit.
For example, the finder intermediate relay is used in the main circuit in parallel with the AC contactor to expand the contacts of the AC contactor and make up for the shortcomings of insufficient use of contacts.
2. Electrical isolation is usually used for control circuits.
It is the principle we usually use: small current controls large current, small voltage controls large voltage, and large current and large voltage in the main circuit are isolated.
Large finder intermediate relays are commonly used, and the wiring is relatively simple. This time, we will focus on the wiring of small finder intermediate relays.
The small finder relay is mainly used in the control circuit of electrical isolation and secondary control.
Let's analyze it from three aspects: structure, principle and wiring:
1、 Structure of small finder intermediate relay
The small finder intermediate relay is generally composed of coil, spring, dynamic and static contacts, small fixed iron core and other components.
It is generally used for the transmission and control of signals (pressure, liquid level, current, voltage, etc.) in the control circuit.
2、 Principle of small finder intermediate relay
The commonly used coil voltage of small finder intermediate relay has three voltage levels: DC24V, AC220V and AC380V.
During operation, when the coil is energized, the finder intermediate relay is pulled in, and the normally open contact of the corresponding finder intermediate relay becomes a normally closed contact, which is used for signal feedback or secondary circuit control. The contact system of the small finder intermediate relay bears limited current and voltage values, so generally, the coil of the AC contactor in the main circuit is only controlled by small current and small voltage, and the large voltage in the main circuit is indirectly controlled.
3、 Wiring of small finder intermediate relay
Precautions for wiring of small finder intermediate relay:
1. Small finder intermediate relays have detailed structure diagrams: distinguish coil contacts from normally open and normally closed contacts.
2. During the use of the small finder intermediate relay: the voltage should be matched, ac220-ac380-dc24 should be distinguished, AC can be divided into positive and negative poles, DC should be distinguished, and the wiring contacts should be clearly seen.
3. When wiring a small finder intermediate relay, control a group of three contacts: common point, closed contact and open contact. Be sure to distinguish the common line.
4. Remember, small finder intermediate relays are generally used in control circuits. Connect small current and voltage. Don't use reverse.