How to maintain DC motor daily
Motor dust, oil and dirt must be thoroughly removed. Any cleaning shall be carried out with the motor uncharged.
Trichloroethylene shall not be used to clean the inside of the motor, but anhydrous compressed air shall be used.
The maintenance of the motor is mainly to check the bearing, commutator, brush holder and brush. Special attention must be paid to the shiny and clean sliding surface of the commutator and good contact with the brush. The surface of the commutator is brown and normal, and the sparks in the brushes are generally caused by mechanical reasons. The deformation of the commutator is not round, the mica plate of the commutator protrudes, the brush in the brush holder is stuck, the rotor is not well balanced, or the installation is not correct, resulting in unstable operation of the motor. In all these cases, appropriate measures must be taken.
When the motor leaves the factory, the inner cavity of the bearing has been filled with No. 3 lithium-based grease of 1/2 to 1/3, and the same or equivalent grease shall be used for re-lubrication as much as possible. There is a straight-through oil cup in the outer bearing cover. In order to prevent excessive grease filling in the bearing cavity, the waste oil should be removed after loosening the bearing cover screws.
The motor commutator has been ground by the manufacturer before leaving the factory. If no damage occurs during transportation, it is not necessary to grind it again during the first drive. Only in the case of external corrosive circulating air erosion and long-term low-load operation in dry circulating air, it is easy to be worn and must be reground. The brush must be lifted as far as possible when the motor is running and cold. Use silicon carbide emery cloth to stick on a concave wood board or rubber block (gold steel emery cloth is not allowed) that matches the outer circle of the commutator. For the out-of-round commutator, use a sharp turning tool to finish turning on the lathe. Mark the minimum allowable diameter of the commutator on the side of the commutator. After turning, use a file or a high-speed steel saw blade to carve 1 to 1.5mm the mica. Then manually chamfer to remove burrs, grind the surface again, taking care that the surface is not contaminated.
For low-power motors, the whole brush is used, and for motors under harsh electrical or mechanical conditions, split brushes with shockproof pads are used. The principle of brush selection is to obtain good commutation performance and operation reliability.
In the case of long-term overload, the brush wear will increase, the brush commutation performance will deteriorate, and the trend of uneven current distribution will increase.
B, low load, low load will often cause the formation of scratches, the base to cause extreme brush wear, this kind of situation in the motor operation should be paid attention.
C, brush pressure, for general medium-power and high-power motors, the correct pressure of the brush is (1.5-2) X 10 Pa when the vibration of the installation place is not great.
D, life, the life of the brush mainly depends on the load and air circulation. At air humidity of 6 to 12 grams of water per cubic meter, the normal wear and tear for 1000 working hours can be at most 5mm. Due to the air humidity or circulating humidity air pollution on the "carbon brush a commutator" characteristics have a great impact, so although the load is normal, the amount of wear will fluctuate by about 100.
E, the formation of scratches, brush cross-section is determined by the rated parameters, for a lighter load brush (I. e. long-term low load operation) may produce scratches, which can reduce the number of brush rod brushes, which can improve the current density of the working brush and prevent the formation of scratches. If the measure is impossible or ineffective. The manufacturer must be consulted. The brush on the original motor is ground, and it is usually not necessary to grind again in the motor debugging, but the movement of the brush in the brush holder and the spring force of the pressure finger (about [1.52] X 10 Pa) should be checked again before use. During operation, the wear rate of the brush shall be controlled and the lead wire of the brush shall be prevented from touching the surface of the commutator.
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Shaoxing Hengli Motor Co., Ltd.
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Address: Building D, Lian Shang Zhizao Industrial Park, Gaocheng Town, Dongguan City, Guangdong Province