Are you getting the best out of your motors?

James Thomas, UK Water Industry Manager, ABB, talks about how the latest generation of high efficiency motors and variable speed drives (VSDs) can help to tackle rising energy costs, and make sizable gains on the road to Net Zero.

With the rising cost of energy showing little sign of abating, the water industry is faced with additional challenges on top of its already ambitious goal of achieving Net Zero by 2030 – 20 years ahead of the government target.

As one of the biggest users of electric motors, the industry employs them in a wide range of applications, from extracting water, treating it and distributing it to customers, all the way to pumping raw sewage and the many stages involved in cleaning it. As such, motors account for a high proportion of energy usage within the industry, making it vulnerable to energy price volatility.

And it’s not just the cost of energy that is exercising the minds of water facility managers. Growing populations are putting more strain on water infrastructure, with pressure growing on the industry to reduce leakage and improve resilience, while keeping a close eye on what PR24 has in store.

The easiest way to save money on energy is simply to use less of it. This is what variable speed drives (VSDs) were designed to achieve. By controlling the speed of motors to match the actual demand of typical water works equipment like pumps or compressors, VSDs can save up to 50 percent of the energy on most pumping applications. This can give an ROI of typically less than three to four years.

Motor technology has also come on in leaps and bounds in the last few years, leading to further energy savings potential. An example is the synchronous reluctance (SynRM) motor, developed by ABB. Matched with an appropriate VSD, a SynRM motor can achieve significant savings, while maintaining performance and reliability.

Rated as IE5, ABB SynRM motors have significantly lower energy losses than comparable IE2 or IE3 induction motors. Their innovative design means they have no losses in the rotor, producing a lower running temperature. Together with the simple rotor design, this cuts the need for service and gives a much reduced failure rate compared to conventional motor designs.

Taking full advantage of these technologies to maximise energy savings will involve water companies adopting a total cost-of-ownership approach (TOTEX) that looks at lifetime costs of the motor.

As part of this, they should be looking to adopt a motor purchasing policy, which should specify a minimum standard the company will use. For example, from the 1st of July 2023, all new motors in the range of 75 kW to 200 kW need to meet the IE4 efficiency standard and IE5 where possible. IE4/IE5 options are already widely available and should be the preferred option.

Motors rated at IE5, also known as ultra-premium efficiency, are greater than 95 percent efficient, compared to the Eff2 motors of 15 years ago which were less than 90 percent efficient.

Another aspect of a motor management policy is deciding whether to opt for the repair or replacement of failed motors. Rewinding was a popular choice in the past, but it can significantly reduce efficiency, giving increased energy costs. It’s often more cost-effective to replace the failed motor with a new high-efficiency motor, with IE5 synchronous reluctance motors being the preferred option.

As we all seek to reduce energy use and mitigate the effects of climate change, motor and drive manufacturers, water companies, OEMs, contractors and regulators can play role in promoting the adoption of high efficiency motors and variable speed drives.

If you have any questions about SynRM, or ABB’s wider motor and drive offering for the water industry, contact me at james.thomas@gb.abb.com.