1. Button switch principle - Introduction
Push-button switch abbreviated button, usually used to connect and disconnect the control circuit, which is a low-voltage electrical appliances in the instruction of a low-voltage electrical appliances, a very wide range of a master electrical appliances in the electrical automatic control circuit for manual Send control signals to control contactors, relays, electromagnetic starters and more. Its features are installed in the work of the machine, instrument, most of the time is in the initial free state position, only when required under the action of external force to the second state (position), when the external force once removed , The switch returns to the initial position due to the action of the spring.
Button switch to start, stop, reversing, speed and interlocking and other basic control. Usually each 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 move at the same time, the normally closed contacts open and the normally open contacts close.
In order to indicate the role of each button, to avoid misuse, usually the button cap made of different colors to show the difference, as shown below. Its color is red, green, black, yellow, blue, white and so on. For example, red means stop button and green means start button. Button switch the main parameters, type, mounting hole size, the number of contacts and the contact current capacity, the product manual has a detailed description.
2. Button switch principle - structure
The button generally by the button cap, reset spring, bridge moving contact, static contact, strut connecting rod and shell and other components.
Button is not subject to external force (ie, static) when the state of contact points, divided into start button (ie normally open button), stop button (ie normally closed button) and the composite button One button). For the start button, when the button cap is pressed, the contact is closed and the contact is automatically disconnected and reset after the button is released. When the stop button is pressed, the contact is separated when the button cap is pressed, and the contact is automatically closed and reset after being released. When the compound button is pressed, the movable contact of the bridge moves downward so that the normally-closed contact is disconnected first, and the normally-open contact is closed. When the button cap is released, the contact is opened normally Break the reset, the normally open contact and then closed to reset.
3. Button switch principle - the working principle
Button switch works better understand the principle as shown below. To put it bluntly, this is the case: there is an electromagnet adsorption device, when you press the button, the inside of the electromagnet magnetically generated on behalf of electricity, and then through the adsorption device to turn the circuit on or off. In order to achieve the remote control circuit and other functions.
Keys are not subject to external force (ie, static) when the contact sub-state, divided into the start button (normally open button), stop button (that is normally closed button) and the composite button One of the keys). For the start button, when pressing the key cap, the contact is closed and the contact is automatically disconnected and reset after being released. When the stop button is pressed, the contacts are separated when the button cap is pressed, and the contact is automatically closed and reset after being released. When the composite button is pressed down, the movable contact of the bridge moves downward so as to close the normally closed contact first; when the keycap is released, the normally open contact first Break the reset, the normally open contact and then closed to reset.