A key factor for energy savings in building services is the use of variable speed drives for compressors, pumps and fans.

There are two decisive factors here: the efficiency of the motor (and the machine) and the energy efficiency of the application control.

Because of their high efficiency, the use of motors with permanent-magnet rotors is increasing. Motors with this technolocy are know as 'EC motors' in the HVAC sector.

To allow the users to benefit from the high motor efficiency of EC technology in all areas, Danfoss has refined its tried and tested VVC+ algorithm - as used in the VLT frequency drives - and optimised it for operating PM motors.