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How To Identify The Carbon Brush Is Good Or Bad?

Jun 22, 2017

How to identify the Carbon Brush is good or bad?
Simple judgment:

It is always good to run without fire.
Current below the rated value, the spring pressure is normal, slip ring (or commutator) smooth, the Carbon Brush contact surface smooth, uniform wear, certainly not flames.
Multiple judgments:
Carbon Brush, also known as the choice of brush on the motor to suppress the spark has an important role, should be power, voltage, load characteristics and commutator circumference speed and other conditions selected. Commonly used electrochemical graphite brush, because of its high resistance coefficient and contact voltage, to inhibit the spark favorable. However, for low-voltage motors, the large contact voltage makes it a large proportion of the total voltage drop, so the use of metal graphite brush.
From the use of view, the use of good performance of the brush signs are the following:
one look
1, see hardness 2, see color 3, see if there are impurities 4, look at the packaging
Dual use
1, whether the start is weak.
2, days cool or battery under the circumstances of a little loss can not start.
3, the electromagnetic switch when the time to stop (that is, driving the gear is not sensitive).
Three wear:
A very important basis for determining the quality of Carbon Brushes is the wear rate of Carbon Brushes. The smaller the wear rate of the Carbon Brush, the longer it will be. The same because the Carbon Brush wear rate at a relatively small time, the relevant equipment operation and maintenance personnel will be relatively small workload, operating costs are very low.
1, the smooth surface of the slip ring on the Carbon Brush will cause some wear and tear: If the smooth surface of the slip ring compared to the high, because of the friction coefficient will be relatively small, then the Carbon Brush wear rate can be reduced The In addition we all know that the surface of the slip ring has a layer of oxide film, the main role is to reduce the slip ring and Carbon Brush between the friction coefficient, so as to reduce the degree of Carbon Brush wear.
2, the pressure of the compression spring will also affect the degree of wear of the Carbon Brush: the pressure of the compression spring must be adjusted moderate, because if the pressure spring pressure is too large, it will increase the mechanical wear of the Carbon Brush; if the pressure spring pressure is too small, Although the friction between the Carbon Brush and the slip ring becomes smaller, it is likely to cause poor contact and sparks.
3, the current will also affect the Carbon Brush wear. Under normal circumstances, the graphite Carbon Brush in the positive Carbon Brush current flow than the negative Carbon Brush current flow is relatively large, casually will cause the positive Carbon Brush wear degree than the negative Carbon Brush wear a little more. And the wear of the positive slip ring is also more than the negative slip ring, then each time the unit overhaul, we can adjust the Carbon Brush by the polarity of the cable head to achieve the purpose of delay wear.
4, Carbon Brush material can also affect the Carbon Brush wear. Different Carbon Brush production business and different Carbon Brush models its composition and structure is not the same, then the Carbon Brush wear rate will not be the same. So we recommend that the majority of customers try to choose the same kind of Carbon Brush, because it can reduce the product model caused by the Carbon Brush is not balanced self-wear rate.
Four models:
Proper selection of the brush model is very important, because the manufacture of brushes used in the selection of raw materials and processes are different, its technical performance is also different. Therefore, when selecting the brush, you should consider the performance of the brush and the motor brush requirements. Brush use performance good signs should be:
1, in the commutator or collector ring surface can quickly form a layer of uniform, moderate and stable oxide film.
2, brush the long life, not wear commutator or collector ring.
3, brush has a good commutation and current collection performance, so that the spark within the allowable range, and the energy loss is small.
4, brush running, but hot, low noise, reliable assembly, no damage.