As one of our commonly used switching devices, relays belong to the category of controllable switches. Relays are widely used, especially in electrical control. Since there are more than one or two types of relays, they are sometimes confused. Next, let's look at the various relays.
Generally speaking, there are three kinds of relays we most commonly use: general relay, control relay and protection relay, whileFinder general relayIt is the product of a brand company.
1、 General relay
This kind of relay is divided into electromagnetic relay and solid-state relay. They not only have protection function, but also have switching function. First of all, as an ordinary relay, electromagnetic relay has only one coil. As long as the coil is energized, it will produce a magnetic field.
In this way, the armature of the relay will be attracted by the magnetic field, so as to promote the action of the relay and drive the contact action of the relay. Generally, electromagnetic relay will bring the following effects: normally open contact closing and normally closed contact opening. When no current passes through the coil, the armature of the relay will automatically return to the original state under the action of the spring, that is, the normally open and normally closed contacts will reset.
In addition, another general relay is solid-state relay, which is different from electromagnetic relay. This relay is a non-contact switch with an internal electronic circuit. We can clearly see that one end of the relay is the input end and the other end is the output end. In fact, the output is a switch. We can open and close the output through some methods. This method is used to adjust the input terminal.
If you want to know the product information of finder general relay, you can consult the customer service personnel.
2、 Control relay
In our common types, such relays include: pressure relay, intermediate relay, fast relay, time relay, etc. Next, we will explain these relays one by one. Among these relays, the intermediate relay is the most widely used because its function is to directly control the load. In addition to this function, it can also control the AC contactor to indirectly control the high-power load
The time relay in the control relay is usually used for the delay circuit; The speed relay is mainly used for the reverse braking of the motor, that is, when the motor is in the braking state and the speed is close to 0, we can stop it by turning off the power switch; As the name suggests, pressure relay is related to pressure. Its function is to sense pressure. When the liquid pressure reaches the set value, the relay contact will act
3、 Protective relay
This kind of relay belongs to the category of protective elements, which can be divided into overload relay, temperature relay, voltage relay, current relay, etc. What is a protective element relay? It is not difficult to understand that the relay can be controlled by the state and value changes of temperature, voltage and other factors
For example, take thermal relay as an example. When the motor is in overload state, it is far greater than the set value. In this way, the large current in the thermal element will cause its own overheating and deformation, thus breaking the contact, thus cutting off the circuit and preventing the expansion of the fault. After cooling for a period of time, its own deformation will slowly reset, and the circuit will be closed and connected. Of course, there are manual reset and automatic reset, which should be adjusted according to the needs of specific circumstances.