Variable-speed three-phase asynchronous motor

Abstract

The invention provides a variable-speed three-phase asynchronous motor which is characterized in that under the condition of no auxiliary device, multispeed running in a broad range is realized, and the shortages of high running cost caused by using a variable frequency speed control asynchronous motor and serious pollution of power grid harmonic wave are solved since the connection of three-phase stator winding and the connection of phase winding and split winding as well as a three-phase asynchronous motor winding structure are changed. The invention has the advantages that the speed control is simple, the cost is low, the multispeed running condition on the three-phase asynchronous motor is satisfied, and the variable frequency speed control motor can be replaced in mechanical equipment capable of realizing multispeed-running in a large scale.

Description

technical field [0001] The invention relates to a three-phase variable-speed three-phase asynchronous motor, in particular to realize the multi-speed operation of the three-phase asynchronous motor by changing the connection method of the three-phase stator winding and the connection method of the phase winding group winding. In some occasions that do not require smooth speed regulation, it can replace the frequency conversion speed regulation asynchronous motor. Background technique [0002] In order to make the three-phase asynchronous motor smooth in a wide range of speed regulation, frequency conversion speed regulation is widely used now. It can not only make the motor speed regulation in a wide range, but also have better operating performance of the motor at different speeds. In terms of motor energy saving, frequency converters have incomparable advantages over other speed control equipment. But its shortcoming is that it needs a frequency converter and its control ...

AI Technical Summary

Problems solved by technology

But its shortcoming is that it needs a frequency converter and its control system, which will increase the operating cost of the motor system, the control system is complex and prone to failure, and the frequency converter used in a large-capacity three-phase asynchronous motor still needs to be imported. When the variable frequency motor is used in some harsh operating environments, due to the problem of the motor control system, it is easy to cause partial discharge of the motor and damage the insulation

[0003] For the modern power grid, the power consumption of the three-phase asynchronous motor accounts for about 70% of the total power of the power grid, and the input current of the low-voltage inverter has a large high-order harmonic component, and these harmonics cause "harmonic pollution" to the power grid. "At the same time, it also reduces the power factor of the inverter input circuit, increases the pulsation of the motor torque and the heat of the motor, thus affecting the insulation of the motor winding, and will also affect other loads running in parallel on the power grid

[0004] Inverter equipment also has the problem of short life. Its life is mainly determined by the electrolytic capacitor. The life of the electrolytic capacitor is directly related to its operating temperature and ripple current. For general variable loads, when the operating environment meets the design conditions, the electrolytic capacitor Lifespan is only about 8 years

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