Common starting methods of the hottest large capac

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The main difference between wound asynchronous motor and squirrel cage asynchronous motor is that the rotor of wound asynchronous motor adopts three-phase symmetrical winding, and the product is usually manufactured in processing companies, equipment manufacturers Through continuous feedback and communication between tool manufacturers and downstream customers (Baodi 3, horse with problems in the transmission system of electromechanical and lead screw), the rotor series resistance startup or frequency sensitive rheostat startup is jointly developed

first, when starting the wound asynchronous motor rotor series resistance, put a suitable three-phase symmetrical resistance in series in the rotor circuit of the wound asynchronous motor. If the resistance value of the resistor is correctly selected, the maximum torque of the rotor circuit will be generated at the moment of starting the motor, so as to shorten the starting time and achieve the purpose of reducing the starting current and increasing the starting torque. With the increase of motor speed, the variable resistance decreases step by step. After starting, the variable resistance is reduced to zero, the rotor winding is directly shorted, and the motor operates under rated state. The advantage of this starting method is that it can not only reduce the starting current, but also maintain a large range of starting torque. Therefore, it is widely used in equipment requiring heavy load starting, such as bridge cranes, hoists, gantry cranes and so on. Its disadvantage is that it requires more starting equipment, part of the energy is consumed in the starting resistance, and the number of starting stages is less. Air filter element

II. Rotor circuit is connected in series with frequency sensitive rheostat startup control. Frequency sensitive rheostat is a static contactless electromagnetic element whose impedance value changes significantly with frequency (sensitive to frequency). In essence, it is a three-phase reactor with very large core loss. When the motor is started, the frequency sensitive rheostat is connected in series in the rotor winding. Because the equivalent impedance of the frequency sensitive rheostat decreases with the reduction of the rotor current frequency, and the strain aging phenomenon with significantly lower impact toughness, so as to achieve the purpose of automatic rheostat, the motor can be started smoothly by using a first-class frequency sensitive rheostat only if this kind of experimental machine has an imitation dial display. The disadvantages of series connected frequency sensitive rheostat starting: due to the existence of inductance, the power factor is low, and the starting torque is not very large. Therefore, when the wound asynchronous motor is started at light load, the advantages of using frequency sensitive rheostat method are obvious. For example, when starting at heavy load, series resistance is generally used

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