Some Knowledge Points of Permanent Magnet Coupler

According to Lenz's law, when the conductor of the permanent magnet coupler moves relatively in a magnetic field, the conductor cuts the magnetic induction line, and an induced eddy current is generated in the conductor, which in turn generates an induced magnetic field, and the two interact to generate torque. Depending on the size of the coupling area, an appropriate torque is generated. The greater the coupling area, the greater the torque.

Permanent magnet speed control technology replaces the valve or baffle that controls the flow or pressure in the original system. By adjusting the meshing area between the permanent magnet rotor and the conductor rotor, the speed regulation of centrifugal loads such as fans and pumps can be realized, and the flow or pressure can be continuously controlled, so as to meet the process requirements and achieve the purpose of economic operation. Compared with the throttle control mode of the valve, the speed control mode of the permanent magnet coupler can save 10% ~ 60% of electricity.

The permanent magnet coupler replaces the original rigid coupling and uses the air gap magnetic field to transmit torque, so that there is no mechanical connection between the motor and the load, so that the vibration on the load side will not be transmitted to the motor side, and the vibration on the motor side will not be transmitted To the load side. The permanent magnet coupler also cuts off the amplification effect of vibration during transmission, so the amplification effect of rigid coupling can be eliminated and the vibration of the system can be reduced. At the same time, the permanent magnet coupler can also reduce the vibration caused by the large centering error. According to the measured data of the permanent magnet coupler in practical application, the vibration of the motor can be reduced by 50 ~ 85% after the transformation.

Because the permanent magnet coupler has no mechanical connection to transmit torque, it has little noise to the environment. Especially for air-cooled equipment, when measured at 1m next to the permanent magnet coupler, the noise is generally below 80dB. It is enough to use a common protective cover without adding a muffler cover.

The permanent magnet coupler is mainly composed of three parts. The conductor rotor and the permanent magnet rotor are pure mechanical components with simple structure, almost zero failure rate and stable performance. The high reliability of the equipment means the following aspects:

(1) The service life of the permanent magnet coupler is 25 to 30 years, the depreciation period is long, and the investment for long-term use is small;

(2) The average fault interval of the permanent magnet coupler is long, the frequency of maintenance and repair requirements is low, and the maintenance and repair cost is low. Bearing grease should be replenished every 2000 hours, bearings, seals and other wearing parts should be replaced every three years.

When the motor starts with load, the current rises instantly, generally 4 to 7 times of the rated current, which lasts for a long time and causes impact on the power grid. The permanent magnet coupler has a light-load starting function. The motor is started first and then loaded. The peak starting current is 4 to 7 times of the rated current of the motor, but the duration is very short, which reduces the thermal shock load of the motor and its impact on the power grid., Thereby prolonging the working life of the motor, effectively reducing the impact of the transmission system on the load when starting, and reducing the starting impact of the transmission system itself, extend the service life of key components such as bearings and seals to ensure safe and reliable operation of equipment. And the service life of the switch to improve the start-stop performance of the system.