scope:

This guideline provides a basis for the selection of variable-speed drives. An integral consideration of drive motor, driven machine and speed control unit as one system is the objective of the guideline. With regard to building services, the consideration of driven machines is limited to fans and pumps.

The following sections include:

• notes on the selection of the variable-speed-drive concept

• notes on the energetic aspects to be considered in selecting variable-speed machines

• notes on potentials for saving energy in specific applications and on improvements of the efficiencies of fans and pumps

• notes on minimum requirements to be met, particularly with electronically controlled drives, in order to achieve fault-free operation

The equations, tables and diagrams in this guideline are intended as recommendations for the users and planners of building services installations.