What is the role of the relay coil?

Update:06-09-2019
Summary:

We should all know the role of the relay. As long as a […]

We should all know the role of the relay. As long as a certain voltage is applied across the coil, a certain current will flow in the coil, which will produce an electromagnetic effect. The armature will overcome the tension of the return spring under the action of electromagnetic attraction. To the iron core, the moving contact of the armature is brought into contact with the stationary contact (normally open contact). The function of the coil is to make the upper coil energize to adsorb or bounce the relevant contact point by input voltage, so as to realize the function of mechanically opening/breaking another set of circuits, thereby realizing the desired output, so the coil is the main component of the relay. Controlling the conversion of electrical energy into mechanical energy.
A relay is a device that is often used as a switch in a circuit. According to the type of control voltage required for its coil, it can be divided into three-phase relays and DC relay. The specification of the relay is expressed by the coil control voltage and the contact current. Usually, the load current is less than 10A, and the circuit can be directly turned on or off by the contact of the relay. If the load current is too large, it can be used as an indirect control device.
In the central air conditioning control system, the relay is often used as a switch for a power supply circuit such as a compressor, a fan motor, a water pump, or a four-way valve. In use, one end of the relay control coil is connected to the power source, and the other end is connected to the output end of the control component. Through the output control signal of the control component, a potential difference is generated across the relay control coil and a current loop is formed to generate an electromagnetic force. Under the action of the electromagnetic force and the inherent elastic force of the relay reed, the relay contacts are pulled or released, thereby turning on or off the circuit of the electrical load power supply to control the operation or stop of the related equipment.

main role:
The principle of electromagnetic is used to realize the conversion of electric energy into mechanical energy to realize the control. The coil and the armature inserted in the coil constitute an electromagnet, and the magnetic force generated by the energization of the coil causes the armature to mechanically move, and drives the contact to complete the circuit. Work to achieve the desired output, so the coil is the main component of the relay. Since the current through the coil is small, the current or voltage controlled by the contact is high. This allows small currents or small voltages to be used to control large currents and high voltages. The purpose of the voltage.
When the relay coil is de-energized, the electromagnetic suction force also disappears, and the armature returns to the original position in the reaction force of the spring, so that the movable contact and the original static contact (normally closed contact) are attracted. This is sucked and released, thereby achieving the purpose of turning on and off in the circuit. For the "normally open, normally closed" contacts of the relay, it can be distinguished as follows: a static contact that is in an open state when the relay coil is not energized, called a "normally open contact"; a static contact that is in an on state It is a "normally closed contact".
We all know the role of relays and coils. In short, the relay coil is an important part of the relay. The relay needs to be coiled for both adsorption and pop-up. The relay must be used with the coil in order to function.