How to get your motor going

Energy efficiency is a key driver for electric motor related standards

One of the earliest IEC technical committees (TCs) prepares the future for electric motors and generators.

motors for conveyor belts
Conveyor belts would not function without electric motors (Photo: © Alex Florstein Fedorov, Wikimedia Commons)

What do conveyor belts, water pumps and elevators have in common? All are powered by electric motors. Motors were arguably one of the key drivers of the Industrial Revolution and they remain indispensable today. One of the first IEC TCs began work on rotating machinery, in 1911. It is still as active as ever and has led the way in helping to improve the energy efficiency of these invaluable devices through its publication of international standards and technical specifications (TS) relating to generators and motors of all sizes.

Key standards on energy efficiency

For example, the IEC 60034 series of international standards is widely used around the world. Regulators, in particular, have taken up the system that ranks motors according to their efficiency classes. Martin Doppelbauer, who is Chair of the TC, has led the work on efficiency classes, which specifies the energy efficiency of motors: “One of the standards we developed is IEC 60034-30-1, which includes an efficiency classification for standard industrial motors. This enables different types of motors to be compared from an energy efficiency point of view”, he explains. Another important standard is IEC 60034-1, which measures the ratings and performance of rotating electrical machines. A new 226-page edition of the document was published in 2017.

While much of the work has been devoted to energy efficiency classification and measurement over recent years, that chapter is about to be closed, according to Doppelbauer. “Most of the standardization work on the energy efficiency of motors is completed. We are planning to issue an energy efficiency guide for motors, but once that document has been published we will turn our focus to maintenance”, he comments.

Maintenance is crucial

Maintaining standards is another key task. Ten maintenance teams deal with aspects as varied as noise emission (IEC 60034-9), synchronous generators (IEC 60034-3) and vibration (IEC 60034-14). Some of the Standards, published in the 1970s, are still in use today. In relation to IEC 60413, which establishes test procedures for determining the physical properties of brush materials for electrical machines Doppelbauer remarks, “We are planning a new edition of this standard, which has been prompted by market requirements. We work from the bottom up and are very receptive to demands coming from various users.”

Doppelbauer expands on the membership of his technical committee:  “We have a high number of observer countries (17) because not all of them manufacture electric motors. However, as they buy and use them, they need to be kept up to date with the most recent technologies and developments. We have a very active number of participating countries (32) although we would welcome more involvement from some large manufacturing countries like Brazil and India.”

More work with ISO further down the line

A new focus area in the coming years will be for motor driven systems that include power electronics. A liaison has been established with the IEC subcommittee for adjustable speed electric drive systems incorporating semiconductor power converters, in order to facilitate the preparation of standards in that area.

There is also planning for collaboration with ISO on the very specific topic of auxiliary energy generators, according to Doppelbauer. The TC already liaises with ISO in the area of internal combustion engines, pumps, and condition monitoring and diagnostics of machine systems.

In the future, there will be greater cooperation  with the IEC TC which covers the overall system aspects of electricity supply systems. This will include, for instance, developing publications relating to the connection and integration of generators with the grid.

“We are looking at power generators which work in an environment strongly impacted by renewable energy systems. One of the issues is how to adapt these generators to fluctuating energy sources like wind and solar”, Doppelbauer explains. Additionally a liaison group has been formed with the European Environmental Citizens Organisation for Standardisation (ECOS), with those same issues in mind.

Last but not least, work with other IEC TCs covers the areas of equipment for explosive atmospheres, winding wires, and evaluation and qualification of electrical insulating materials and systems.

Looking forwards, some of the 14 publications in the pipeline include, the first edition of IEC 60034-33 and specifying the technical requirements for hydro generators or the second edition of IEC 60034-2-3, which establishes the test methods for determining losses and efficiency of converter-fed Alternative Current (AC) motors.

The technical committee for rotating machinery has contributed widely to the world as we know it today. Its work remains relevant as it prepares for a future in which renewable energy systems will be widespread and sensors will be used in devices we would never even have thought of, as recently as couple of years ago.