Beautiful Plants For Your Interior
When you buy an electric tool, you will find that some products come with two small accessories in the box. Some people know that it is a carbon brush, but some people don’t know what it is called or how to use it.
Today, I will give you a detailed introduction to what a carbon brush is, what it does, and the difference between a brushed motor and a brushless motor.
Part 1. What are carbon brushes used for?
Nowadays, whether it is poster promotion or sales introduction, the brushless motor of power tools is a major selling point. Carbon brushes are widely used in electrical equipment to transmit signals or energy between the fixed part and the rotating part of some motors or generators.
It has a rectangular shape and a metal wire installed in the spring. Carbon brushes are a sliding contact part, so they are easy to wear and need to be replaced regularly and the worn carbon deposits need to be cleaned.
Part 2. Working principle and difference
All motors are composed of a stator and a rotor. In a DC motor, in order to make the rotor rotate, the direction of the current needs to be constantly changed, otherwise the rotor can only rotate half a circle. This is like pedaling a bicycle with one foot. One foot can only pedal half a circle, so the DC motor needs to change the current in the rotor, that is, to change the direction of the current-carrying conductor when it needs to be changed.
Brushless DC motors use electronic commutation, without commutators and carbon brushes, but use position sensors.
The position sensor energizes the adjacent stator coil according to the position of the rotor’s magnetic poles, allowing the stator to generate magnetic poles that attract the rotor, which can attract the rotor to rotate, and this repetition can drive the motor to rotate.
The brushed motor uses mechanical commutation. The external magnetic poles are stationary while the internal coils are moving. When the motor is working, the commutator and the coils rotate together, and the carbon brushes and the magnets are stationary, so friction is generated between the commutator and the carbon brushes to complete the switching of the current direction.
In addition, the commutator of the brushed motor produces friction with the carbon brush. Long-term use of the carbon brush has the risk of carbon powder falling off. It cannot be used in dust-free workshops and explosion-proof workshops and needs to be replaced regularly.