What are the speed regulating methods of AC motors? What are the characteristics of each?
One, change pole logarithmic speed regulation method: change the stator winding of the red way to change cage motor stator pole count, to speed.Two, frequency conversion speed control method: use frequency converter to change the motor stator power frequency, thus change its synchronous speed regulation method.Three, cascade speed regulation method: cascade speed regulation refers to winding motor rotor circuit series into adjustable additional potential to change the motor differential, to achieve the purpose of speed regulation. Most of the differential power is absorbed by an additional potential added into the series, and then additional equipment is added to return the absorbed differential power back to the grid or to convert energy to use. According to the method of differential power absorption and utilization, cascade speed regulation can be divided into motor cascade speed regulation, mechanical cascade speed regulation and thyristor cascade speed regulation, and thyristor cascade speed regulation is adopted.
1, motor speed smooth, can be adjusted according to the speed, is the future development direction of AC motor; (FM), 2, star delta conversion, generally in large motor starting with star start, triangle operation, reduce the starting current. (adjust the magnetic pole logarithm) 3, and there is double speed, three speed motor, increase the winding, mainly change the stator winding connection method to change the speed. There are two factors that change the speed of a pole: the magnetic pole, the logarithm, and the frequency
Winding motor rotor series resistance speed control method: line induction motor rotor series of additional resistance, so that the motor slip increases, the motor at a lower speed operation. The greater the resistance in series, the lower the speed of the motor. This method is simple in equipment and convenient in control, but the differential power is consumed in the form of heating. The utility model belongs to a class speed regulation, and the mechanical characteristics are softer.
