Causes of Overheating of Collector Ring Brushes Due to Mechanical Friction

Among the overheating faults of the collector ring brushes due to mechanical friction, a large part of the overheating faults are caused by mechanical and frictional reasons. Overheating caused by friction and other reasons: a large part of the overheating faults of the collector rings and brushes are due to overheating caused by mechanical and frictional reasons. If the temperature is high, or the temperature is too high during operation, after pulling out a few brushes, the temperature decreases instead, which is basically due to mechanical and frictional reasons.

The situation of heating caused by machinery and friction is very complicated, mainly in the following three aspects:

(1) The contact surface between the brush and the collector ring is too small, and the contact area should generally not be less than 75% of the cross section of a single brush. The brush contact surface is poorly ground or too many brushes are replaced at one time during operation. Replace the brushes during operation. At the same time, only 1-2 brushes are allowed to be replaced on each carbon brush holder. The replaced new brushes should be ground on a model with the same diameter as the collector ring in advance, and the old and new grades must be the same. If there are many brushes to be replaced at one time during overhaul, sufficient time should be left for the oxide film to form on the surface of the brushes when rushing before putting into operation. The contact surface between the brush and the collector ring is too small, and the contact area should generally not be less than 75% of the cross section of a single brush.

(2) The electric brush is swaying or stuck in the brush box. The brush should be able to move up and down freely in the brush holder, and the gap should meet the product regulations. When there is no regulation, the gap can be 0.10-0.20mm. The shape of the brush should be square, and the size error of the upper and lower ends should not be greater than 0.05mm.

(3) The gap between the brush holder and the surface of the collector ring is too large. Due to the brittle material of the brush, when the gap between the brush holder and the surface of the collector ring is too large, the brush cannot contact the collector ring as a whole during operation, and it is in inclined contact with the collector ring, which is easy to cause the brush to crack. The gap between the brush holder and the surface of the collector ring should meet the technical requirements of the product. When the product is not specified, the gap can be adjusted to 2-3mm. When adjusting the gap, a layer of 2-3mm thick rubber pad can be used to attach the collector ring. surface, place the brush holder against the rubber pad, then tighten the set screw to remove the rubber pad.