Why do air compressors use permanent magnet synchronous motors?

In industrial production, air compressors are major energy consumers, and the performance of their motors directly determines operating costs, efficiency and reliability. The essence of equipping air compressors with permanent magnet synchronous motors lies in utilising the motor’s unique technical structure to address the pain points associated with traditional asynchronous motors in air compressor applications, such as ‘high losses, low efficiency and large size’.

The adoption of permanent magnet synchronous motors in air compressors represents a comprehensive optimisation achieved through technological upgrades, delivering ‘cost reduction, efficiency improvement, space saving and reduced maintenance’. Particularly given the current trend in the industrial sector towards green energy conservation and precision manufacturing, this has become the mainstream direction for upgrading air compressor motors.

From the perspective of energy conservation and consumption reduction, traditional asynchronous motors require electrical energy to generate an excitation magnetic field, with rated efficiencies typically ranging between 85% and 92%; efficiency drops sharply, particularly under low loads. However, during the actual operation of air compressors, the load is constantly fluctuating, resulting in significant energy wastage. Javisonmotors’ permanent magnet synchronous motors, utilising flat magnetic wire and high magnetic resistance technology, achieve a rated efficiency of up to 97.5 %. Furthermore, they maintain a high level of efficiency even when operating at low loads. When combined with variable frequency drive technology, energy savings in variable-load scenarios exceed those of traditional models by more than 20 per cent, leading to significant long-term cost reductions.

In terms of space and installation requirements, under the same power rating, traditional asynchronous motors are bulky and heavy, resulting in the air compressor occupying a large amount of space. Permanent magnet synchronous motors, however, utilise the strong magnetic field properties of permanent magnets to achieve higher power density; they are smaller and lighter than asynchronous motors, allowing for a more compact air compressor design and saving installation space.

In terms of operational stability and air quality, air compressors must continuously deliver stable air pressure; otherwise, this can easily lead to faults in pneumatic equipment or product defects. Traditional asynchronous motors suffer from ‘slip’, which causes pressure fluctuations; in contrast, permanent magnet synchronous motors maintain strict synchronisation between rotational speed and frequency, and can respond rapidly to changes in air demand, working in conjunction with the control system to minimise pressure fluctuations. Furthermore, as the motor operates at a lower temperature, it reduces the risk of downtime caused by overheating, thereby enhancing the overall operational stability of the unit.

From the perspective of long-term operational and maintenance costs, permanent magnet synchronous motors feature a rotor without windings, resulting in a simpler structure; they can even incorporate sealed designs to minimise the impact of dust and oil contamination on internal components. At the same time, their ‘smooth running’ characteristics extend the service life of components such as bearings and the motor housing, indirectly reducing long-term expenditure on equipment replacement and maintenance.