Kaeser Compressors (Fredericksburg, VA) has redesigned its Sigma Frequency Control (SFC) 45, 55, 75S, 90S and 110S compressors with advanced SynRM motor-drive combinations. These 60-125 hp units offer better part-load efficiency, longer service life and reduced maintenance costs. Developed in partnership with Siemens and specifically designed to work with Kaeser's SFC models, the SynRM motor-drive combination achieves top tier IES2 classification. This results in better specific performance, especially in the part-load conditions that call for variable speed compressors.
They do not use aluminum, copper, or expensive rare earth metals in the rotors. Instead, they are made of electrical steel and feature a special profile. With this unique rotor design, the motors run cooler - resulting in lower bearing and winding temperatures and increased motor life. And because there are no magnets in the rotor, motor service is safer and easier.