Micro-motor carbon brush
Micro-electric motor brush life expectancy shorter than the large-scale electrical machinery, but the use of household appliances is shorter, therefore, a group generally can use the brush a few years in the life of electrical brush need to be replaced during the examples of many .
Material from the brush of a general can select a low friction coefficient and contact voltage drop of larger graphite electric brush, resin binder for the high resistance of natural graphite brush can be used for the poor motor. In addition, more abrasive strong carbon-graphite brush is mainly used mica sudden ultra-small motor.
Series Motor speed easy to adjust, but with a resistor or transformer to adjust the speed of motor at low speed with lower torque. In order to improve the situation, the use of electronic control of motor speed to increase, which is cheap to run for half-wave, brush-for-life than full-wave to the even shorter, so this is a noteworthy problem.
If the increase in design-for-up to the number of films, or select a large brush cover coefficient (for the brush thickness and thickness ratio), then tends to increase brush wear. Brush cover coefficient generally take 1-3 Comparison ideal. mica insulation under the engraved depth of more than 0.5MM. because brush size smaller, so mica thickness thinner than the large motor is much more, which reduces the vibration of brush are favorable. additional experience that the prediction brush life is very difficult, especially in small brush, high-volume production of motor fluctuations in large prediction difficult is one of the reasons.