Because not just the efficiency of the individual components is what matters, but rather the result of their interaction. And that is where RadiPac excels with outstanding values.
As the impeller, motor and electronics are optimally coordinated, overall efficiency levels well in excess of 60% are obtained. A major contribution to this comes from the EC motor with external rotor.
This is a line-operated, permanently excited synchronous motor with electronic commutation (also known as BLDC).
Its efficiency levels far surpass the requirements of efficiency class IE4, without the use of problematic rare-earth magnets. The design of other internal rotor permanent magnet motors achieving comparable efficiency makes rare-earth magnets essential. They are also less compact and less easy to install and commission on account of the external control electronics required.