Introduction to the Specific Structure and Characteristics of Button Switch
Release time：2019-07-12 Clicks： Click
What is the specific structure and characteristics of the button switch? Next we will give you a detailed introduction, please see the following.
Introduction of Button Switch
Button switch (English name is push-button switch) refers to the use of buttons to drive the transmission mechanism, so that its dynamic contacts and static contacts press on and off and realize circuit switching switch. Button switch is a simple, widely used master electrical appliances. In the electric automatic control circuit, it is used to manually send out control signals to control contactors, relays, electromagnetic starters and so on.
There are many kinds of button switches, which are generally divided into ordinary button-pressing type, mushroom head type, button switch self-locking type, self-resetting type, handle type, indicator type, symbol type and key type, etc. There are single button, double button, three buttons and different combination forms, generally using building block structure, with button cap and reset spring. Bridge contacts and outer shells are usually made into composite type, with a pair of normally closed contacts and often open contacts. Some products can increase the number of contacts through series connection of multiple components. There is also a self-supporting button, which can automatically keep the closed position after pressing, and can only be opened after power failure.
The button switch can complete the basic control of starting, stopping, reversing, changing speed and interlocking. Usually each button switch has two pairs of contacts. Each pair of contacts consists of a constant open contact and a constant closed contact. When the button is pressed, two pairs of contacts act at the same time, and the contacts are usually closed, and the contacts are often opened and closed.
In order to mark the function of each button and avoid misoperation, the button cap is usually made into different colors to show the difference. The colors are red, green, black, yellow, blue, white and so on. For example, red means stop button, green means start button, etc. Main parameters, type, size of mounting hole, number of contacts and current capacity of button switch.
2. Structure of Button Switch
The structure of the button switch is composed of a button cap, a reset spring, a fixed contact, a movable contact, a shell and a support connecting rod. The main categories are as follows.
1. Often open contact (moving contact): refers to the original state (electrical appliances are not yet subject to external force or coil is not electrified), fixed contact and movable contact in a separate state of contact.
2. Normally closed contact (dynamic break contact): refers to the original state (electrical appliances are not yet subject to external force or coil is not electrified), fixed contact and movable contact in the closed state of contact.
3. Normally open (turn on) button switch, when not pressed, the contact is disconnected, when pressed, the contact is closed and connected; when loosened, the button switch is reset and disconnected under the action of reset spring. In the control circuit, the often-opened button is often used to start the motor, also known as the start button.
4. Contrary to the normal open button switch, the contact is closed at the end of pressing, and the contact is disconnected when pressing. When the hand is released, the button switch is reset and closed under the action of reset spring. Normally closed buttons are generally used to control motor parking, also known as self-reset buttons.
5. Compound button switch: a button switch that combines the normal open and normal closed button switches, i.e. it has the normal closed contact and the normal open contact. When not pressed, the normally closed contacts are closed and the frequently opened contacts are disconnected. When pressing the button, the normally closed contacts are first disconnected and then closed, which can be considered as self-locking buttons. When the button switch is loosened, under the action of the reset spring, the normally open contacts are first disconnected, and then the normally closed contacts are closed. The compound button is used in the interlocking control circuit.