Three kinds of switch electrical appliances, I do not know how many people can not tell

In the power system, circuit breakers , contactors, and relays seem to be familiar guys, but many of them are ignorant, but they can't figure out how these things are different, and what is the connection. Let's talk about it today.

Let me say the same first! Of course, it is beyond reproach, that is, these guys are all kind of switch electrical appliances , what is called a switch, it is easier to understand, can complete the opening and closing action, are switches, therefore, these things are switch.

Therefore, these so-called differences, that is, the difference in the form of the switch. In this way, is it easy for everyone to understand?

First, the circuit breaker

Its definition is very simple: it refers to a switching device that can close, carry and break the current under normal loop conditions and can close and carry current under the abnormal loop condition within a specified time.

Second, the contactor

A contactor is an electrical appliance that uses a current flowing through a coil to generate a magnetic field in an industrial power to close the contacts to achieve a controlled load.

â–² contactor

Third, the relay

A relay is an electrical control device that is an electrical device that causes a predetermined step change in the controlled output quantity in the electrical output circuit when the change in the input amount (excitation amount) reaches the specified requirement .

â–²Relay

From the above block, perhaps you already know that circuit breakers and relays are used in electrical primary circuits, which can be used to cut off large currents, while relays are used in electrical secondary circuits. Switch off small currents.

So what is the difference between a circuit breaker and a contactor?

â–²Typical application

The above figure is a typical application of the motor's positive and negative control. As you can see, the circuit breaker protects the electrical overcurrent and overvoltage . However, the contactor controls the motor after the coil is turned on according to different start signals.

In short, the power system is actually very simple, mainly power, transformers, wires, electrical equipment and switches, all complex circuits can be broken down into the above four parts.

It’s really hard to make it simple!