ELECTRIC POWERTOOL CARBON BRUSHES
At present, the increasing popularity of home electrification. Frequently used in home electrical use of the carbon brush has (extracted vegetable juices, fruit juice of) crushing machine, mixer, electric razor, electric fader haircut, air dryers, vacuum cleaners, angle grinder, electric hammer, electric drill , cutting machine, grinding wheel machine, trimming machine, curve sawing, electric-ho, impact drill, screwdriver machine, hot, and movie projectors, such as mower. In addition to power tools rock drilling machine, sandblasting machine and polishing machine, the carpentry and the use of electric shaver cutting machine is also gradually universal.
For these are almost all the electrical equipment 100 volt AC power AC-DC dual-use electric motors, motor efficiency from considerations, should pay attention to the extent of its light, so they are characterized by small, high-speed and high torque. Design and because of economic reasons, each winding turns more so for the permit is usually bad, and as large as the non-electric sparks change to the exception. In addition, there is reason for producing sparks in the commutator surface finish bad, eccentric shaft, carbon brush and brush grip inappropriate location and inappropriate, such as the gap between the commutator, which is unique to small electrical problem.
Because strings are used in electric motor, so easy to adjust the speed, but with a resistor or transformer to adjust the speed of motor at low speed to reduce 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, carbon brush for longer than full-wave to the even shorter, so this is a noteworthy problem.
Small motor with carbon brush life expectancy shorter than the large-scale electrical machinery, but the use of home electrical short time, therefore, a group of carbon in general can use a few years in the life of electrical carbon brushes need to be replaced during the examples of many .
From the carbon material considerations, the general can select a low friction coefficient and contact voltage drop of the larger electric carbon graphite, and binder resin as a high resistance of natural graphite for carbon brush can be applied to the special non-performing motor. In addition, the current is limited to mica sudden application of ultra-small electric grinding strong carbon graphite brush.