ODM High Performance AC Motor Low Maintenance Rare Earth NdFeB Material

Differences Between The Permanent Magnet Motor And Asynchronous Motor:

01. Rotor Structure

Asynchronous motor: The rotor consists of an iron core and a winding, mainly squirrel-cage and wire-wound rotors. A squirrel-cage rotor is cast with aluminum bars. The magnetic field of the aluminum bar cutting the stator drives the rotor.

PMSM Motor: The permanent magnets are embedded in the rotor magnetic poles, and are driven to rotate by the rotating magnetic field generated in the stator according to the principle of magnetic poles of the same phase attracting different repulsion.

02. Efficiency

Asynchronous motors: Need to absorb current from the grid excitation, resulting in a certain amount of energy loss, motor reactive current, and low power factor.

PMSM Motor: The magnetic field is provided by permanent magnets, the rotor does not need exciting current, and the motor efficiency is improved.

03. Volume And Weight

The use of high-performance permanent magnet materials makes the air gap magnetic field of permanent magnet synchronous motors larger than that of asynchronous motors. The size and weight are reduced compared to asynchronous motors. It will be one or two frame sizes lower than asynchronous motors.

04. Motor Starting Current

Asynchronous motor: It is directly started by power frequency electricity, and the starting current is large, which can reach 5 to 7 times the rated current, which has a great impact on the power grid in an instant. The large starting current causes the leakage resistance voltage drop of the stator winding to increase, and the starting torque is small so heavy-duty starting cannot be achieved. Even if the inverter is used, it can only start within the rated output current range.

PMSM Motor: It is driven by a dedicated controller, which lacks the rated output requirements of the reducer. The actual starting current is small, the current is gradually increased according to the load, and the starting torque is large.

05. Power Factor

Asynchronous motors have a low power factor, they must absorb a large amount of reactive current from the power grid, the large starting current of asynchronous motors will cause a short-term impact on the power grid, and long-term use will cause certain damage to the power grid equipment and transformers. It is necessary to add power compensation units and perform reactive power compensation to ensure the quality of the power grid and increase the cost of equipment use.

There is no induced current in the rotor of the permanent magnet synchronous motor, and the power factor of the motor is high, which improves the quality factor of the power grid and eliminates the need to install a compensator.

06. Maintenance

Asynchronous motor + reducer structure will generate vibration, heat, high failure rate, large lubricant consumption, and high manual maintenance cost; it will cause certain downtime losses.

The three-phase Permanent magnet synchronous motor drives the equipment directly. Because the reducer is eliminated, the motor output speed is low, mechanical noise is low, mechanical vibration is small, and the failure rate is low. The entire drive system is almost maintenance-free.

The three-phase Permanent magnet synchronous motor drives the equipment directly. Because the reducer is eliminated, the motor output speed is low, mechanical noise is low, mechanical vibration is small, and the failure rate is low. The entire drive system is almost maintenance-free.

Advantages of asynchronous motor:

1. High initial cost: Permanent magnet AC motors are more expensive than other types of motors.

2. Limited torque: These motors have limited torque capability, which makes them unsuitable for high-torque applications.

3. Temperature sensitivity: Permanent magnets can lose their magnetism at high temperatures, which can affect the motor's performance.

4. Risk of demagnetization: If the motor is subjected to a strong magnetic field, the permanent magnets can become demagnetized, which can cause the motor to fail.

5. Limited speed range: Permanent magnet AC motors have a limited speed range, which makes them unsuitable for applications that require high-speed or variable-speed operation.

6. Difficult to control: These motors are difficult to control because they have a fixed magnetic field, which makes it challenging to adjust the speed or torque.

7. Limited size range: Permanent magnet AC motors are typically smaller than other types of motors, which limits their application in larger machines.

8. Environmental concerns: The production of rare earth magnets, which are used in permanent magnet AC motors, can have environmental impacts due to the mining and processing of these materials.

Disadvantages of asynchronous motor:

1. Lower efficiency: Asynchronous motors have lower efficiency compared to synchronous motors, especially at low loads.

2. Limited speed control: Asynchronous motors have limited speed control options. They can only be controlled by changing the frequency of the power supply, which is not always feasible.

3. Higher maintenance: Asynchronous motors have more moving parts compared to synchronous motors, which makes them more prone to wear and tear. This increases the maintenance requirements and costs.

4. Lower power factor: Asynchronous motors have a lower power factor, which means they draw more current from the power supply and can lead to higher energy costs.

5. No self-starting: Asynchronous motors require an external power source to start, unlike synchronous motors that can self-start.

6. No precise synchronization: Asynchronous motors do not have precise synchronization with the power supply, which can lead to fluctuations in the motor speed and torque.

7. No constant torque: Asynchronous motors do not have constant torque across the entire speed range, which can limit their use in certain applications.