Introduction to the structure of mining motors
2022-08-17 10:06
Mining motor Structural form
Mining motor The structure, protection, and insulation grade should meet the requirements of the installation and use environment. According to the regulations of China's "Coal Mine Safety Regulations", explosion-proof motors should be selected in coal (rock) outburst mines and gas outburst roadways; in the mine pits of gas mines, general-purpose motors can be used in general air intakes or main air intakes; in mine air intakes, main return air passages, main return air passages, mine return air passages, working faces and air intake working faces, explosion-proof motors should be selected for air intakes, usually explosion-proof motors.
Mine DC traction motors consist of motor armatures, commutators, carbon brushes, etc., which are troublesome to maintain, and the carbon brushes are easily worn parts and often need to be replaced, and the maintenance cost is high. Mine frequency conversion AC motors replace the DC traction motor rotor with a squirrel-cage rotor (no copper head carbon brushes, coils), greatly improving the airtightness of the component combination, thus effectively avoiding the problem of reduced insulation performance caused by working environment problems (such as humidity, high temperature, etc.), and eliminating the steps of opening components and cleaning the rotor carbon powder in real time, thereby improving operational reliability. Basically no maintenance is required. The reliability of use of DC traction motors has a huge impact on speed regulation, and the wear and tear on gears is relatively large. Frequent use of hand brakes can cause significant damage to brake pads. Mine frequency conversion AC motor vehicles run smoothly, so they will not produce strong impact forces, thus effectively protecting the brake pads, reducing the occurrence of faults, and eliminating the use of starting resistors, thereby reducing maintenance costs and difficulty. Speed regulation performance, the speed of DC traction motors varies with the load, especially when running downhill, if the motor speed is too fast, accidents may occur, and sudden acceleration may also cause the motor and controller to burn out. Frequency conversion AC motors can maintain uniform speed regulation, unlike DC traction motors, which experience sudden changes in speed. According to the principle of technical and economic rationality, select the motor type, voltage level, structural type and cooling method to ensure the reliable operation of the driving motor. For example, large and medium-sized high-voltage motors are used for lifting equipment such as ventilation, drainage, and compressed air, and high voltage uses 6kV or 10kV to achieve economical and reasonable power supply; according to the principle of equipment power supply and power supply voltage level, mining working face machinery motors should use 660V, 1140V or 3.3KV voltage. When it is difficult to dissipate heat from the motor with external fan cooling, it is advisable to use a water-cooled motor with an outer casing; there is a lot of rock dust on the excavation working face, so the auxiliary motor of the excavator generally uses an explosion-proof casing cooling method, without an external fan, to reduce rock dust flying.
Mining motor There should be appropriate reserve power, and the load rate of general mining motors is generally between 0.8 and 0.9. However, for mining excavation machinery motors with large load fluctuations, it is necessary to analyze specific situations such as overload and blockage, select special motors, and use high-temperature resistant F and H insulated motors to improve operational reliability.
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