The motor uses the principle of electromagnetic induction to realize the electric energy and the AC motor are commonly used in the daily production process, especially the three-phase asynchronous motor. Because it has the advantages of simple structure, sturdy and durable, reliable operation, low price and convenient maintenance, Dalan Motor tells you that they are widely used to drive various metal cutting machine tools, cranes, forging presses, conveyor belts, casting machinery, power. Not large fans and pumps. Chain Link Gate,Chain Link,Black Chain Link Fence,Chain Link Fence Gate Hebei Haiao Wire Mesh Products Co., Ltd. , https://www.haiaowiremeshfencing.com
The mechanical characteristics of a three-phase asynchronous motor refer to the relationship between the rotational speed of the motor and the electromagnetic torque of the motor.
The electromagnetic torque of a three-phase asynchronous motor is expressed in the following three ways:
1, physical representation
The physical representation can directly reflect the physical nature of the electric motor "target=_blank> machine electromagnetic torque, which fully demonstrates that the electromagnetic torque and rotor current will reflect the role of electromagnetic torque.
2, parameter representation
The parameter representation is an expression of the relationship between electromagnetic torque, power supply parameters, and electric parameters. This method can analyze the change of parameters and the influence of electromagnetic torque on mechanical engineering.
3, practical representation
Practical notation is one of the most common and easy to remember. The indicators that can reflect the starting performance and capability of the motor are the maximum torque and the starting torque. The larger the values ​​of the two indicators, the stronger the performance of the motor and the better the starting effect.
The mechanical characteristics of the three-phase asynchronous motor exhibit a nonlinear curve form. Usually, the value of the maximum torque is used as the demarcation point, and the linear part is stable, while the nonlinear part is unstable.
In the case of man-made conditions, the mechanical characteristics can be studied by parameter representation to find the maximum torque, so that the three-parameters of critical slip and starting torque and above can be used to formulate the transformation law.
The three-phase asynchronous motor is divided into a small capacity and a large capacity, while a small capacity can be directly activated at the time of starting, and a large-capacity motor can adopt a more advanced step-down starting method.
The buck start is also divided into the following three forms:
1. Reactance buck start or stator series resistor start
During start-up, the current decreases with decreasing voltage, and the starting torque decreases with the square factor of the voltage, which is usually suitable for lighter start-ups.
2, auto-transformer step-down start
The auto-transformer startup mode can be used for large-capacity startup, which reduces the torque directly to the original 1/k2.
3, YD step-down start
In normal operation, the YD start mode can be used. This start mode can quickly reduce the current and torque to 1/3 of the original.
The wound rotor method of the asynchronous motor can utilize the resistance series connection mode of the rotor and the frequency sensitivity of the resistor to increase the torque and reduce the current, thereby being suitable for starting the large-capacity motor.
The soft starter is a new type of control device. Its main advantage is a new type of device capable of soft start, light load energy saving and fast integration. Its main feature is that it has a series power supply to control the motor. The thyristor controls the electronic circuit.
The soft starter is used to connect the power supply to the motor, and the conduction angle in the thyristor is controlled in different ways, so that the input voltage in the motor can be gradually increased from zero value, and the entire voltage is given to the start of the motor. On the motor, this method is called soft start.
In fact, the soft starter is a voltage regulator, which is a regulator that changes the voltage without changing the frequency when the motor is started.
----- Editor-in-Chief: Dalan Oil Pump Motor 02-Procurement Consultant
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