Copper busbar manufacturers come to tell you why motor brushes do not use pure copper?-Jiangsu Xindake Connection Technology Co., Ltd.

Copper busbar manufacturers come to tell you why motor brushes do not use pure copper?

Source: http://www.kingdco.com/en/news/119.html Published: 2018-01-29

Do you know why motor brushes do not use pure copper? This might be unfamiliar to everyone. So next,Copper bus manufacturerLet's talk about:

Copper bus manufacturer

It can be said that there are no pure copper brushes, because pure copper is relatively soft, wears out easily, and does not have a self-lubricating effect. Even toy motors use at least copper alloys. What you referred to as pure copper is probably a copper-graphite brush.
Common types of brush materials include: graphite; metallic graphite
Common types of electric brushes include: electrochemical graphite brushes, copper graphite brushes, power tool brushes, electric scooter brushes, spring brushes, automotive motor brushes, silver graphite brushes, and more.
Precautions for using brushes:
To ensure the normal and safe operation of the motor, correct installation and proper maintenance of the brushes are very important and should be given full attention.
1. Installation of the carbon brush: To ensure that the carbon brush can move freely in the brush holder, the gap between the carbon brush and the brush holder is generally kept between 0.1-0.3 millimeters. If the gap is too small, the carbon brush is prone to getting stuck due to thermal expansion; if the gap is too large, the carbon brush can swing in the brush holder, causing sparks or damage. The manufactured carbon brush is generally made according to standard tolerances or user requirements for thickness and width.
2. Replacement of the brushes: Brushes are consumable components in the motor. When the brushes are worn to a certain extent (i.e., the safe limit), they need to be replaced with new ones. Whether the brushes of a motor are replaced all at once or in batches, brushes of the same model should be used to prevent imbalanced current distribution among parallel brushes due to differences in brush performance, which could affect the normal operation of the motor.
3. Arcing of the brushes: In order for the brushes to make good contact with the commutator (or slip rings), new brushes should be arced when first used so that the contact surfaces match. Factory-made brushes are only roughly arced, and arcing is generally performed on the motor in use.
4. Spring pressure: In a motor, the spring pressure on the brushes should be calculated accurately and evenly, both during installation and during use. It should be measured regularly with a spring scale or similar instrument. If the spring pressure is uneven, the brush subjected to higher pressure will bear a larger current load, which can easily cause brush overheating, oxidation and loosening of flexible connectors, and sparking.
5. Formation of the oxide film: The surface where the commutator (or slip ring) contacts the brush forms a brownish oxide film (the color of the oxide film varies depending on the brush type), which is normal. It not only facilitates commutation but also changes the friction mechanism, reducing wear during friction. Therefore, it should be properly protected and should not be wiped off.
6. Identification of sparks: The occurrence of larger sparks is a direct manifestation of poor commutation in a DC motor. The causes of sparks are complex, including electrical reasons as well as mechanical, chemical, and physical factors. Sparks caused by electrical reasons are called "commutator sparks," which are usually blue and distributed under the brushes. Sparks caused by mechanical reasons are called "mechanical sparks," which are often yellow in color and have long sparks.
According to the standards issued by the ministry, sparks are divided into the following levels: Level 1 has no sparks; Level 5/4 has only a small portion of weak point-like sparks under the brush; Level 3/2 has most of the area under the brush with slight sparks; Level 2 has sparks under the entire edge of the brush.
7. Daily Observation: To ensure the normal operation of the brushes, daily observation and recording are also very important. The main aspects to observe and record include: spark level, brush sliding noise, brush vibration, wear degree, the surface condition of the commutator (or slip ring) (oxidation film formation), load conditions, as well as other factors such as temperature and humidity, and regularly summarize the findings.
To properly select a carbon brush, the brush model must be chosen according to the electrical characteristics of the motor; the brush size must be chosen according to the size of the brush holder; and the brush structure must be chosen according to the type of brush grip structure.
The above information has been compiled by the editor from the internet, and we hope it is helpful to you. Yixing Xindake New Energy Technology Co., Ltd. is a professional copper busbar manufacturer producing copper foil flexible connectors, stamping parts processing, and other high and low voltage components. You are welcome to call us for consultation. We will provide you with the most professional and highest quality service to answer your questions. Thank you for your support.