Adding a drive to meet energy regulation

Part of a European motor efficiency standard allows use of a variable speed drive to meet energy-saving requirements.


Interior permanent magnet (IPM) motors are one of many solutions to motor efficiencies above premium levels. In a cooling tower fan application, this direct-drive IPM motor (and adjustable-speed drive) eliminated a worm-gear reducer used with a two-speedPhases 2 and 3 of European Union regulation EC No. 640/2009 mandate use of IE3 class motors starting in 2015 and 2017—depending on motor size range (see main article, "Motor-Driven Systems Efficiency Update," linked at the bottom). However, the regulation includes a notable option. In lieu of an IE3 motor, it allows the following “or” option: “…or meet IE2 efficiency and be equipped with a variable speed drive [VSD].” As far as it’s known, this is the only efficiency standard to date where a VSD is formally included.

There is good reason for this provision. VSDs (also called variable frequency drives, VFDs) can match motor output to changing load conditions in variable-torque applications, thereby cutting energy losses. Indeed, the EU is counting on the huge number of such pump, fan, and compressor applications—reportedly 2/3 of all applications—to deliver meaningful efficiency gains through use of a drive. Of course, an IE3 motor and VSD combination would be even more efficient, but marketing issues have held off earlier European adoption of the higher IE-class motor.

Meanwhile, VSDs and motor-drive combinations are drawing attention from the efficiency viewpoint. While VSDs are quite efficient at nominal speed/torque, with losses typically amounting to 2%-5%, at 25% speed/torque VSD losses can reach 10%-30%, according to Ref. 2. These factors must be assessed or improved, if possible, when implementing drive systems.

One development in this area is Canadian Standards Association (CSA) draft standard C838, Energy Efficiency Test Methods for Three-Phase Variable Frequency Drive Systems. Covering drive and motor combination “systems,” CSA C838 establishes appropriate testing requirements and procedures that compare efficiency at different system speed and load points. The basis of this draft standard derives from the work of Pierre Angers, an engineer with Hydro-Quebec of Canada, and it has been cited earlier in Control Engineering (Ref. 9). CSA C838 is a work in progress, with the comments period having closed on April 8, 2012.

See the main article, “Motor-Driven Systems Efficiency Update,” for further motor system efficiency developments, linked at the bottom of this article.

- Frank J. Bartos, PE, is a Control Engineering contributing content specialist. Reach him at 

No comments
The Top Plant program honors outstanding manufacturing facilities in North America. View the 2013 Top Plant.
The Product of the Year program recognizes products newly released in the manufacturing industries.
The Engineering Leaders Under 40 program identifies and gives recognition to young engineers who...
A cool solution: Collaboration, chemistry leads to foundry coat product development; See the 2015 Product of the Year Finalists
Raising the standard: What's new with NFPA 70E; A global view of manufacturing; Maintenance data; Fit bearings properly
Sister act: Building on their father's legacy, a new generation moves Bales Metal Surface Solutions forward; Meet the 2015 Engineering Leaders Under 40
Cyber security cost-efficient for industrial control systems; Extracting full value from operational data; Managing cyber security risks
Drilling for Big Data: Managing the flow of information; Big data drilldown series: Challenge and opportunity; OT to IT: Creating a circle of improvement; Industry loses best workers, again
Pipeline vulnerabilities? Securing hydrocarbon transit; Predictive analytics hit the mainstream; Dirty pipelines decrease flow, production—pig your line; Ensuring pipeline physical and cyber security
Upgrading secondary control systems; Keeping enclosures conditioned; Diagnostics increase equipment uptime; Mechatronics simplifies machine design
Designing positive-energy buildings; Ensuring power quality; Complying with NFPA 110; Minimizing arc flash hazards
Building high availability into industrial computers; Of key metrics and myth busting; The truth about five common VFD myths

Annual Salary Survey

After almost a decade of uncertainty, the confidence of plant floor managers is soaring. Even with a number of challenges and while implementing new technologies, there is a renewed sense of optimism among plant managers about their business and their future.

The respondents to the 2014 Plant Engineering Salary Survey come from throughout the U.S. and serve a variety of industries, but they are uniform in their optimism about manufacturing. This year’s survey found 79% consider manufacturing a secure career. That’s up from 75% in 2013 and significantly higher than the 63% figure when Plant Engineering first started asking that question a decade ago.

Read more: 2014 Salary Survey: Confidence rises amid the challenges

Maintenance and reliability tips and best practices from the maintenance and reliability coaches at Allied Reliability Group.
The One Voice for Manufacturing blog reports on federal public policy issues impacting the manufacturing sector. One Voice is a joint effort by the National Tooling and Machining...
The Society for Maintenance and Reliability Professionals an organization devoted...
Join this ongoing discussion of machine guarding topics, including solutions assessments, regulatory compliance, gap analysis...
IMS Research, recently acquired by IHS Inc., is a leading independent supplier of market research and consultancy to the global electronics industry.
Maintenance is not optional in manufacturing. It’s a profit center, driving productivity and uptime while reducing overall repair costs.
The Lachance on CMMS blog is about current maintenance topics. Blogger Paul Lachance is president and chief technology officer for Smartware Group.