Compared with the power frequency motor, the permanent magnet synchronous motor is easy to control, the speed depends on the power frequency, and the operation is stable and reliable, and does not change with the load and voltage fluctuations. In view of the strict synchronization of the speed of permanent magnet synchronous motor, the motor has good dynamic response performance, which is more suitable for frequency conversion control.
Permanent magnet motor is a kind of energy-saving motor, which has been well promoted in many application fields. But not all working conditions and occasions must use or be suitable for using permanent magnet synchronous motor, which is a problem worth discussing.
Theoretically, permanent magnet synchronous motor is more suitable for load types with frequent load changes. The motor often operates under no-load or light load conditions such as lathe, punch, chemical fiber, textile, wire drawing, etc. The final energy-saving effect is obvious, with an average energy-saving rate of more than 10%.
In many cases, especially when the cage motor is selected, in order to make the equipment start smoothly, the motor will be selected according to the maximum load of the equipment in most cases, which will inevitably lead to a relatively low load rate and a serious excess capacity of the motor during normal operation. When the motor is running, the efficiency is related to the load. Generally speaking, when the motor operates with no load, the efficiency is close to zero. When the load increases, the efficiency will also increase. When the rated load reaches 70%, the efficiency is the highest; Therefore, when the motor runs close to the rated load, the efficiency is the highest and the energy saving is economical. If the matched asynchronous motor is replaced by a high starting torque permanent magnet synchronous motor, the result of configuring energy input on demand will play a great role in energy saving. The advantages of permanent magnet synchronous motor are two low and two high, namely low loss and temperature rise, high power factor and efficiency. This is also the pursuit of motor performance, which determines the market application position of permanent magnet motor.
Therefore, when selecting the matching motor, the customer should conduct a comprehensive analysis based on the actual equipment and working conditions, not only staying in the motor body, but also fully considering the energy saving effect of the system.
