1 for the protection of the normal operation of the motor, the correct choice of brush models is very important because of the selection of raw materials and processes in the manufacture of brushes, its technical performance differences. Therefore, when selecting the brush, it should be comprehensive consideration of the requirements of the brushes performance and motor brush. Brush a good indicator of the use of performance should be as follows:
a commutator or collector ring surface can quickly form a uniform layer, moderate and stable oxide film.
b brush long life and does not wear the commutator or collector ring
c brush having a good commutation and the current collecting performance, so that the spark suppression within the allowable range, and the energy loss is small.
d brush run, but the heat, noise, reliable assembly, no damage.
2. Brush loaded grip within the brush to be guaranteed to be able to move freely up and down, the brush and the brush holder the inner wall of the clearance is between 0.1-0.3 mm in order to avoid the brush and the brush holder into the gap is too large swing. Brush Woxia edge away from the commutator surface, the distance should be kept at about 2 mm. If the distance is too small, the brush holders likely to be injured commutator, the distance is too large, the brush is easy fibrillation caused the damage.
On the same motor principle, should use the same type of brush, but for individual commutation particularly difficult for large and medium-sized motor, twin brush can be used, slide it into the side of good lubricating properties, slide the edge using curbed the spark ability of the brush, so that the operation of the brush is improved.
Brush wear to a certain degree to replace it with a new brush, the brush is the best time to replace all the old and new mix, may occur the phenomenon of uneven current distribution. For large units, downtime replacement brushes, is bound to affect the production, you can choose the non-stop, we usually recommend customers practice every time you replace 20% of the brush (that is, each motor brush rod 20%), each interval of 1-2 weeks, to be run and then gradually replace the rest of the brush, to ensure the continuous operation of the unit normal.
5 in order to make good contact brush and commutator, the new brush should be grinding radians, grinding radians generally be carried out on the motor. A fine glass sandpaper placed between the brush and the commutator, in a normal under spring pressure, in the direction of the motor rotating grinding brush, the sandpaper should stick tight commutator, until the brush cambered anastomosis, and then remove sandpaper, with compressed air blowing dust, use a soft cloth to wipe clean. The abrasive brushes should not be used emery paper to prevent The Emery particles embedded the commutator tank when the motor is running, abrasions brushes and commutator surface. After grinding arc, the motor first 20-30% load operation for several hours, the brush and commutator adjustments, and the establishment of a uniform oxide film. And then gradually increase the current to the rated load.
Impose on the same motor brush unit pressure should be uniform, in order to avoid the current unequal distribution of individual brush overheating and spark. The brush unit pressure should brush technical performance table to select for high rotational speed of the motor or motor work under vibration conditions, an appropriate increase in the unit pressure, one guaranteed to work. For example: traction machine motor brushes unit pressure 0.4-0.6kgf/cm2.
Usually brush unit pressure is too high brush wear increased unit pressure is too small, contact unstable and prone to mechanical sparks.