Working principle explanation of mining motors
2022-07-28 13:28
Mining Motor Working principle description
Mining motors can be classified according to their working principle, installation method, and operating environment. According to the working principle: Three-phase AC asynchronous motor, powered by a three-phase AC power supply, the rotor speed is always lower than the speed of the rotating magnetic field. Since the rotor winding current is induced, it is also called an induction motor. According to its different structures, it can be divided into cage rotor asynchronous motor - cage rotor winding, cage rotor asynchronous motor - rotor winding and stator winding are also equipped with three-phase windings, and are connected to the asynchronous motor through slip rings, brushes and external resistors. According to power and voltage level, it can be divided into large and medium-sized high-voltage asynchronous motors with a power of 220kW and above, and a voltage of 6kV or 10kV; small and medium-sized low-voltage asynchronous motors with voltages of 127V, 380V, 660V or 1140V; according to the required speed, it can be divided into dual-speed, multi-speed (three-speed, four-speed), slip differential electromagnetic speed regulation, voltage regulation and switched reluctance speed regulation motors, etc. AC synchronous mining motor. Mining Motor A motor that converts AC electrical energy into mechanical energy, and its rotor rotates at the same speed as the magnetic field. Mining types are mostly high-voltage motors with a voltage of 6kV.
DC mining motor. A motor that converts DC electricity into mechanical energy. Mining DC motors include large DC motors for lifting equipment, DC traction motors or explosion-proof DC traction motors. Linear motor. A motor whose running part moves linearly. Linear induction motors used underground in coal mines are mostly linear induction motors, which can be divided into planar, cylindrical, disc, arc, and drum types according to their structure or arrangement.
According to the operating environment:
General mining vehicles. Suitable for gas-free or well-ventilated areas. Mining Motor Including explosion-proof mining motors and enhanced safety mining motors. Motors used at the mining face are all explosion-proof motors. The selection of mining motors should follow the following principles: meet the load characteristics, working system, torque, starting, acceleration, braking, overload capacity, speed change and other requirements of the drive equipment. For example, water pumps, air compressors, and exhaust fans have stable loads, and the motor is an S1 working system; synchronous motors are mostly used for large-capacity air compressors. Although the specified working system is S1, it must meet the requirements of frequent starting, blocking, and overload. The cutting motor of the roadheader requires a large torque, and the working system is S1 or S4; the motor of the loading machine is the S2 working system. Therefore, according to the specific situation of mining machinery, it is necessary to choose a special motor to meet the needs.
According to the principle of technical and economic rationality, select the type, voltage level, structural type and cooling method of the motor to ensure the reliable operation of the drive. 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 face machinery motors should use 660V, 1140V or 3.3KV voltage. When it is difficult to dissipate heat with an external fan-cooled motor, it is advisable to use a water-cooled motor with an outer casing; there is a lot of rock dust at the mining face, so the auxiliary motor of the roadheader generally uses an explosion-proof casing cooling method, without an external fan, to reduce rock dust flying.
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