We should all knowFinder relayAs long as a certain voltage is applied at both ends of the coil, a certain current will flow through the coil, resulting in electromagnetic effect. The armature will overcome the tension of the return spring and attract to the iron core under the attraction of electromagnetic force, so as to drive the dynamic contact and static contact (normally open contact) of the armature to attract. The function of the coil is to enable the charged coil to absorb or spring off the relevant contacts through the input voltage, so as to mechanically connect / disconnect another group of circuits, so as to achieve the desired output. Therefore, the coil is the main component of the finder relay, which plays the role of converting electrical energy into mechanical energy to achieve control.
Finder relay is a device often used as a switch in circuits. According to the type of control voltage required by the coil, it can be divided into AC relay and DC relay. The specification of finder relay is expressed by coil control voltage and contact current. Generally, when the load current is less than 10a, the contact of finder relay can be directly used to connect or disconnect the circuit. If the load current is too large, it can be used as an indirect control device.
In the central air-conditioning control system, finder relay is often used as the switch of compressor, fan motor, water pump, four-way valve and other power circuits. When in use, one end of the finder relay control coil is connected with the power supply, and the other end is connected with the output end of the control part. Through the output control signal of the control part, the potential difference is generated at both ends of the finder relay control coil, forming a current loop and generating electromagnetic force. Under the action of electromagnetic force and the inherent elasticity of relay reed, the contact of finder relay is pulled in or released, so as to connect or disconnect the circuit of electrical load power supply, so as to control the operation or shutdown of relevant equipment.
Main functions of finder relay:
According to the principle of electromagnetism, electric energy is converted into mechanical energy to realize the control function. The coil and the armature inserted in the coil form an electromagnet. The magnetic force generated by the energization of the coil will make the armature move mechanically and drive the contact to complete the work of connecting or disconnecting the circuit, so as to achieve the required output. Therefore, the coil is the main component of the finder relay. Because the current passing through the coil is very small, the current or voltage controlled by the contact is high, so as to achieve the purpose of controlling large current and high voltage with small current or small voltage.
When the coil of the finder relay is powered off, the electromagnetic suction will also disappear, and the armature will return to its original position under the reaction force of the spring, so that the moving contact and the original static contact (normally closed contact) will be pulled in. In this way, the connection and disconnection in the circuit can be achieved. The normally open contact and normally closed contact of finder relay can be distinguished as follows: the static contact in the disconnected state when the coil of finder relay is not energized is called normally open contact; The static contact in the on state is called "normally closed contact".