VFD (Variable Frequency Drive)
A VFD controls the speed of an electric motor by varying the frequency of its power supply. By matching motor speed to actual demand instead of running flat-out and throttling, VFDs cut energy use sharply on pumps and fans — often one of the highest-return efficiency measures.
Because pump and fan power scales with the cube of speed, modest speed reductions yield large energy savings, so VFDs frequently pay back fast on variable-load duties. They also reduce mechanical stress and enable soft starts. VFD electrical signatures are additionally a rich source for motor condition monitoring.
Related terms
Energy Management System (EnMS / EMS) · Condition Monitoring · Predictive Maintenance (PdM)
Related guides
Software
Where this applies
Matching a pump to its system curve · Optimising cooling tower performance · Floating refrigeration head pressure · Deciding to rewind or replace a failed motor · Adopting a motor management policy