Control methods and characteristics of automatic winding machines

The working principle of AC frequency converter: Frequency conversion technology is a technology that changes the power frequency through a frequency converter, thereby changing the speed of an AC asynchronous motor. By first converting AC to DC through a frequency converter, and then converting DC to AC through a frequency converter, the speed of the AC motor is controlled.

The series of circular winding machines in the automatic protection device project of the winding machine control the frequency converter by controlling the analog voltage of the input frequency converter, and then controlling the frequency of the output power supply of the frequency converter, so that the speed of the AC motor changes with the frequency of the output power supply.

The speed of a three-phase asynchronous motor is determined by the point frequency, the number of pole pairs of the motor, and the slip rate. The torque of an asynchronous motor is generated by the interaction between the magnetic flux of the motor and the current flowing through the rotor. At a fixed frequency, if the voltage is constant and only the frequency is reduced, the magnetic flux will be too large, the magnetic circuit will be saturated, and in severe cases, the motor will be burned out. Therefore, the frequency and voltage should be changed proportionally, that is, while changing the frequency, the output voltage of the frequency converter should be controlled to maintain a certain magnetic flux of the motor and avoid the occurrence of weak magnetism and magnetic saturation. Due to the general use of V/f control in general frequency converters, that is, variable voltage and variable frequency control, changing the frequency and voltage to achieve the optimal motor control method.

Therefore, the variable frequency speed regulation method was chosen, which is a speed regulation method that changes the frequency of the stator power supply of the motor, thereby changing its synchronous speed. Its characteristics:

① High efficiency, no additional losses during the speed regulation process;

② Wide application range, suitable for cage asynchronous motors;

③ Wide speed range, hard characteristics, and high accuracy.

Transformers generally consist of an iron core, coil, casing, and necessary insulation materials. The coils of transformers are generally divided into high voltage coils and low voltage coils. High voltage coils are generally wound with circular insulated wires, while low voltage coils are generally wound with flat insulated wires or foil. The coil winding of transformers is the core process of transformer manufacturing, which has a significant impact on the performance of transformers. It not only directly determines the main economic and technical indicators such as the external dimensions, losses, and weight of the transformer, but also directly affects the main quality indicators such as the mechanical performance, insulation performance, and heat resistance of the transformer. The traditional winding of transformer coils relies on manual winding of insulated wires onto the workpiece according to production process requirements, and the resistance is counted by the operator. Adopting traditional winding methods not only results in low winding efficiency, but also poor quality of the finished coil. At present, automatic winding machines are commonly used for winding transformer coils, which can significantly improve production efficiency and wiring accuracy. In automatic winding machines, there are vertical winding machines for winding large transformers, as well as horizontal and foil winding machines for winding transformers of lower voltage levels and smaller capacities.

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