The difference between power frequency and permanent magnet frequency conversion

There are significant differences between the power frequency motor and the permanent magnet frequency converter motor in many aspects. The following is a detailed explanation of their differences:

1. Definition and working principle

• Industry frequency motor:
  • Definition: Also known as a synchronous speed motor, it refers to an AC motor that operates at a power frequency of 50Hz or 60Hz.
  • Working principle: Based on the principle of electromagnetic induction, the rotating magnetic field generated by the stator interacts with the current in the rotor, generating torque to drive the motor to rotate.
• Permanent magnet frequency converter motor:
  • Definition: A motor that can adjust the power supply frequency within a certain range. Using a permanent magnet as a rotor, the power supply frequency is adjusted through the inverter to achieve precise control of speed and torque.
  • Working principle: Based on the principle of electromagnetic induction, the coil on the stator will generate a rotating magnetic field after passing through the alternating current, and the permanent magnet on the rotor will be attracted or repelled by the magnetic field, thereby generating a rotational torque. Since the magnetic field strength of the permanent magnet is proportional to the current frequency, the change of the current frequency will cause the rotation torque to change, thereby achieving the speed regulation of the motor.

2. Performance characteristics

• Power frequency motor:
  • Speed ​​and torque: Operate at a constant power supply frequency, the speed and torque are relatively fixed.
  • Structure and Design: Usually standard design is adopted, with simple structure and low manufacturing cost.
  • Reliability and Maintenance: High reliability and low maintenance costs.
  • Application: Suitable for applications that require low-precision control, such as mechanical manufacturing, water pumps, fans, compressors, etc.
• Permanent magnet frequency converter motor:
  • Speed ​​and torque: Adjust the power supply frequency through the inverter to achieve precise control of speed and torque, with high flexibility and adaptability.
  • Structure and Design: In order to meet the needs of frequency conversion speed regulation, special designs have been carried out in the structure, such as high-performance insulating materials and thermal conductivity materials to improve the heat resistance and heat dissipation of the motor.Performance; Optimize electromagnetic design and rotor structure to improve motor efficiency and performance.
  • Reliability and Maintenance: Although the structure is relatively complex, due to its high efficiency and precise control, the maintenance cost is relatively low (considering the small impact on the power grid and small mechanical impact, extending the service life of each part).
  • Application: Suitable for applications that require high-precision control, such as steel, petroleum, chemical, electricity, transportation and other fields, as well as fans, water pumps, conveyor belts, robots, etc.

3. Energy-saving and environmentally friendly

• Industrial frequency motor: Working at a constant power supply frequency, its energy consumption and efficiency are relatively fixed. Due to the unadjustability of rotation speed and torque, there may be a problem of high energy consumption under certain operating conditions.
• Permanent magnet frequency conversion motor: Adjust the power supply frequency through the inverter to achieve precise control of speed and torque, thereby improving energy efficiency. In addition, permanent magnet frequency converter motors also have the advantages of low noise and low vibration, which is conducive to improving the working environment and reducing noise pollution.

4. Other considerations

• Cost: Due to its simple structure and low manufacturing cost, the initial investment cost of the power frequency motor is relatively low. Although the initial investment cost of permanent magnet frequency converter motors is relatively high, due to their high efficiency and precise control, energy and maintenance costs can be saved in the long run.
• Technical maturity: The industrial frequency motor technology is already very mature and widely used. The permanent magnet frequency conversion motor technology is also constantly developing. With the development of high-power electronic devices and AC speed regulation systems, its speed regulation performance and economy are comparable to those of DC motors.

In summary, there are significant differences in operating principles, performance characteristics, energy saving and environmental protection, and cost of the power frequency motor. When choosing a motor type, you should comprehensively consider the actual needs and working conditions to select the most suitable motor type.