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The permanent magnet direct drive motor is a special type of motor. An important feature that distinguishes it from other motors is that it does not require the use of a conventional reduction mechanism. Reducers are often used to convert the high speed rotation of a motor to a lower speed output for different applications. Permanent magnet direct drive motors, through their unique design and operating principle, are able to directly provide the required output speed, thus eliminating the need for a reducer.
What is a reducer
A reducer is a mechanical transmission device used to reduce the speed and increase the torque of a motor’s output. It usually consists of components such as gears and bearings, and works by converting the input of a high-speed rotating motor into a lower-speed but higher-torque output.
Function and working principle of reducer:
The main function of a reducer is to convert the input of a high-speed rotating motor into a lower-speed output suitable for a particular application, while increasing the torque of the output. It meets the speed and torque requirements of different applications and provides a more stable output.
A reducer works by converting speed and torque through the co-ordination between gears or other transmission elements. The input shaft is connected to the motor, which feeds high-speed rotational power into the reducer. The combination of these gears or transmission elements achieves different reduction ratios, thereby reducing the output speed and increasing the output torque.
Classification of reducers:
Gear reducer: Gear reducers use gears to convert the input speed. Common types include helical gear reducers, cylindrical gear reducers and bevel gear reducers.
Worm reducer: The use of worm gears and worms to achieve a reduction in output speed and increase in torque.
Planetary reducer: Consisting of a planetary gearing system, this reducer is capable of providing high reduction ratios and compact construction.
Why permanent magnet direct drive motors do not require a reducer
Permanent magnet direct drive motors are a special type of motor that has the advantage of directly driving a load without the need for a reducer. There are several reasons why permanent magnet direct drive motors operate without a reducer:
High torque density: Conventional asynchronous motors have a limited starting torque multiplier and maximum torque multiplier. Therefore a reducer is required to reduce the speed and increase the torque. Under normal operating conditions, the motor is in light load operation and its power factor is relatively low. Permanent magnet direct drive motors use highly efficient permanent magnets as the excitation source inside the motor, and they have high magnetic field strength and magnetic energy density. This enables permanent magnet direct drive motors to produce a higher output torque with less volume and weight without a reducer, meeting the power required by the load.
High rpm: Permanent magnet direct drive motors typically have a high rpm range and can directly provide the required rpm without the need to reduce the rpm through a reducer. This reduces the complexity of the system and reduces energy losses during energy conversion.
High Efficiency: Permanent magnet direct drive motors are able to directly convert the high speed output of the motor into the low speed required by the load. In contrast, a reducer introduces additional mechanical transmission losses that reduce the efficiency of the system. Therefore, permanent magnet direct-drive motors have lower energy losses during the energy conversion process and higher energy conversion efficiency.
Fewer transmission components: Permanent magnet direct drive motors do not require a reducer, which reduces the number and complexity of parts in the transmission system. This reduces system maintenance costs and improves the reliability and stability of the overall system.
Low noise and maintenance costs: Conventional motor systems that use reducers can sometimes be noisy due to the gearing noise and friction loss that reducers typically cause. Permanent magnet direct drive motors, on the other hand, do not require a reducer and therefore have lower noise levels. In addition, reducers require regular maintenance and replacement of parts due to issues involving gear wear and lubrication, whereas permanent magnet direct drive motors have relatively low maintenance costs.
Applications of permanent magnet direct drive motors
Permanent magnet direct drive motors are widely used in many applications due to their high torque density, high efficiency and high precision control. The following are some of the common application areas for permanent magnet direct drive motors:
Machine tool industry: Permanent magnet direct drive motors have important applications in machine tools and machining equipment. Their high torque density and high precision control make them ideal spindle drives. The high rotational speed and high responsiveness of permanent magnet direct drive motors enable faster cutting speeds and higher productivity.
Textile Machinery: In the textile industry, precise motion control is needed to adjust the working speed and tension of textile machinery. Permanent magnet direct drive motors provide highly accurate speed and torque control and are suitable for use in stepper drive systems and continuously variable transmission systems for textile machinery.
Solar and wind power generation: Permanent magnet direct drive motors are increasingly used in the field of renewable energy. They are used as drivers for wind turbines and solar tracking systems, providing efficient energy conversion and stable power output.
The application of permanent magnet direct drive motors is not limited to the above fields, but is also widely used in other industrial fields and mechanical equipment to meet different motion control needs. With the continuous progress and innovation of technology, the prospect of permanent magnet direct drive motors in more fields will be further expanded. With all the advantages that “no reducer”’ brings, permanent magnet direct drive motors will be more widely recognized.
