Variable speed drives (VSDs)

Variable speed drives (VSDs)
© yanik88, image #140215688, 2017, source:
All sectors
Investment cost:
High cost
Payback time:
0.5 Year(s)
Cost savings:
14975€ / Annual: £13739 (€ 14975.51)
Resource type:
Resource saving:
Annual: Greater control of pumps and reduced energy consumption (proportional to a cube of the power reduction). 152653 kWh. 28157 kg CO2e
Investment cost:
7630€ / £7,000 (€ 7,630) for VSD purchase and installation. The scale of the project is based on pump size. Risks associated with this installation are minimal. Once installed, maintenance is minimal. Staff time may be required for programming of VSD.
Assumptions taken in the presentation of the above performance indicators:

Installation of VSD on existing pump.    Applications where the full capacity of a pump is not required constantly and where greater control of pumps is sought.    55 kW swimming pool pump currently in use 168 hours per week.  VSD installed to allow flow rate reduction in hours when site is closed (61 hours per week).

VSDs prove that speed really is relative after all

Variable speed drives (VSDs) – also known as drive frequency converters, adjustable speed drives, or inverters – are an increasingly popular measurement and control system in industry.

VSDs can adjust electricity supply to an AC induction motor, automatically and accurately changing its speed and torque output to match real-time demand on the machine.


Installing VSDs could save energy, cut costs and increase profit margins. Using a VSD to slow down a fan or pump motor, for instance, from 100 % to 80 % could save as much as 50 % on energy use. These savings are dependent on the specific use of the VSD.

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