| |

Saving the Planet, and Money

Saving the Planet, and Money, with the Affinity Law for Pumps and Fans

January 12, 2023

Affinity law
Affinity Law states if a pump / fan speed is changed, flow rate is directly proportional to the speed, whereas the head / flow is directly proportional to the square of the speed

Reducing energy, this has been and will continue to be a hot topic in Canada. There are many ways to do this, the best of course is to not use power but we all know that this can’t happen as the word keeps turning.

One very successful option to reduce your power consumption is with centrifugal pump and fan applications. If you are still using dampers, bypasses or throttling valves to control your system you simply utilize a drive / VFD like ABB’s ACQ580. Add a feedback device like a pressure transducer, flow sensor or building automation system to control and reduce the motor speed when possible based on system requirements.

affinity law for fans and pumps

In these systems the “Affinity Law” states if a pump / fan speed is changed, flow rate is directly proportional to the speed, whereas the head / flow is directly proportional to the square of the speed. In plain terms a reduction in speed by “x” percent reduces the flow equally while reducing the required power which is a cube of the driven speed.

See here a quick example of the affinity law using ABB’s online ABB Energy Save Calculator of a 50Hp pump if switched from a throttling valve to VFD control on a standard bell curve running 24 /7 that will save you $14350.00 a year !

Take a look at the pumps and fans in your facility, then see the chart to see the effective power savings and also the reduction in your power consumption and lowered utility bill ! The larger the motor the more money you can save .

Related Story

Ultra-Low Harmonic Drives for Increased Efficiency and Reliability of Processes and Systems

Related Products

ACQ580 drives for water and wastewater

Related Articles



Editor’s Pick: Featured Article

Weidmüller’s u-control 2000: The Automation Controller

Weidmüller’s u-control 2000: The Automation Controller

Weidmüller’s scalable engineering software, u-control 2000, adapts individually to your requirements. And, the u-control is powerful, compact and fully compatible with Weidmüller’s I/O system u-remote. This article looks at what makes u-control the heart of your automation.

Programmable logic controllers (PLCs) are one of the main components of any automated system. A typical control system has inputs, outputs, controllers (i.e., PLCs), and some type of human interaction with the system, a human machine interface (HMI), for example.

Read More



Latest Articles

  • Why Use Low-Consumption Contactors in Your Motor Control Systems?

    April 15, 2025 By Tiffany Moore Organizations are under more pressure than ever to improve sustainability metrics. How can you help them succeed — and win more business in the process?    Building motor control systems with more sustainable parts is one piece of the puzzle. Control panel builders, system integrators, and design firms have an… Read More…

  • The Long Cable Run Dilemma: Where Should You Install the VFD?

    April 15, 2025 By Damien Herwegh Sophia, a dedicated electrical engineer in a large industrial complex, has been tasked with installing a drive system where the motor is located hundreds of meters away from the control room. Like many engineers before her, she considers the usual question: Should I place the drive in the electrical… Read More…