Push-button switch refers to the switch that uses the button to push the transmission mechanism, make the moving contact and the static contact are connected or disconnected and the circuit is changed. Push-button switch is a kind of master electrical appliance with simple structure and wide application.
In an electrical automatic control circuit, it is used to manually send control signals to control contactors, relays, electromagnetic starters, etc.
There are many types of button switch structure, which can be divided into ordinary snap button type, mushroom head type, self-locking type, self-reset type, handle type, with indicator light type, with lamp symbol type and key type, [1] there are single button, double button, three button and different combination forms, generally using building block structure, composed of button cap, reset spring, bridge contact and shell, etc., usually made into compound type. There are a pair of normally closed contacts and normally open contacts, and some products can increase the number of contacts through the series of multiple components. There is also a self-supporting button, which can automatically maintain the closed position after being pressed, and can be opened after the power is turned off.
Push-button switch can complete basic control such as start, stop, reverse and reverse rotation, speed change and interlock. Usually each push-button switch has two pairs of contacts. Each pair of contacts consists of a normally open contact and a normally closed contact. When the button is pressed, the two pairs of contacts act at the same time, the normally closed contact is disconnected, and the normally open contact is closed.
In order to indicate the role of each button and avoid misoperation, the button cap is usually made into different colors to show the difference, and its colors are red, green, black, yellow, blue, white and so on. For example, red indicates the stop button, green indicates the start button, and so on. The main parameters, type, mounting hole size, number of contacts and current capacity of the contacts of the button switch are detailed in the product manual.
