Carbon brushes need to be replaced after the degree of wear, but if the carbon brush is to be replaced, it is recommended to replace all the carbon brushes at once.If the new brush is mixed with the old one, the current distribution may become uneven.
For various types of large electric units, in the case that the replacement of carbon brush due to the stop will affect the normal production, we can generally suggest that 20% of the carbon brush should be replaced each time, that is, 20% of each brush rod of one motor.In this way, it takes about 1 to 2 weeks to replace each time. After phased familiarity, the rest of the carbon brushes can be replaced.
However, many of our customers need to pay attention to is that, on the same motor, when replacing the carbon brush, we should try to use the same type of carbon brush, but even if the individual commutation is particularly difficult for the medium-sized motor, you can also use the twin carbon brush.Gemini brushes are better at sliding, so a brush that can slide and suppress sparks is used.
Check the carbon brush and slip ring daily.The main inspection items are as follows.
1. The wear length of the carbon brush should not exceed 2/3.Replace the brush if it is worn for more than 2/3 of its length .
2. The situation where the carbon brush does not spark.When the carbon brush starts to spark, it is necessary to find out the reason and eliminate it immediately.
3. The carbon brush does not bias the outside of the slip ring, and the edge of the carbon brush does not collapse.
4. Carbon brush braid, brush grip and carbon brush are well connected, no heat, will not touch the brush grip.
5. When the carbon brush shakes, shakes and has no astringency in the brush grip.
6. Regularly use a DC clamp meter to measure the current sharing of each carbon brush evenly, and use an infrared thermometer to measure whether the carbon brush is overheated. If abnormal, replace it immediately.
7 spring pressure is normal, no deformation and fracture phenomenon.Under normal conditions, the pressure of each carbon brush must be uniform and stable.The unit pressure is usually between 1.1kg~2.5kg, and the uneven pressure difference between the carbon brushes should be less than 5%.
8. The distance between the brush grip and the slip ring conforms to the specified value.The distance between the generator brush bracket and the slip ring: 2.5~3 mm, the distance between the main excitation brush bracket and the slip ring: 2~4 mm.
9. No discoloration, overheating and uneven wear on the surface of the slip ring. The surface temperature of the slip ring should be below 120.
10. There is no dirt in brush grip and brush grip.When scale is more, clean it with a brush or remove it with compressed air.Properties, grades and adjustment methods of carbon brush sparks.