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The March TO IE4

15 March 2013

Andy Pye expands on some of the developments at WEG towards meeting the yet-to-be ratified electric motor IE4 efficiency standard

For signatories to the Kyoto Protocol, 2012 was a year of great importance - when parties to the legally binding protocol reported on their efforts, in respect of lowering the overall emissions from six greenhouse gases (carbon dioxide, methane, nitrous oxide, sulphur hexafluoride, HFCs, and PFCs).

CALL TO ACTION
The Kyoto Protocol was flawed of course – the USA is not a signatory, and Canada withdrew in 2011 – but it has proved to be a call to action across many energy- intensive market sectors. What all these sectors have in common is their use of electric motors, which are the single biggest consumer of electricity worldwide, used to drive pumps, fans, compressors and other mechanical traction equipment. They account for about two thirds of industrial power consumption and about 45% of global power consumption, according to a new analysis by the International Energy Agency. Some 300 million electric motors are in use in industry, infrastructure and large buildings and roughly 30 million new ones are sold each year for industrial purposes.

Unsurprisingly, in view of these figures, electric motors have been one of the main target areas for improving energy efficiency. The resulting efforts in this area have generated new energy efficiency standards, such as the latest IEC 60034-30:2009, a harmonised IE (International Efficiency) grading standard, which is central to the EU’s new eco-design directive 2005/32/EC.

Many manufacturers have anticipated the new standard, and have produced energy efficient products to comply. But is this enough, bearing in mind that every standard is a compromise, in the final analysis? One company, WEG thinks not, and has exceeded the requirements of standards in its latest motor and drive designs – both LV and MV. This despite the fact that only meeting the IE2 standard for electric motors is now mandatory. The IE3 standard won't be enforced until 2015 and no date has been confirmed for the IE4 rating.

Furthermore, IEC 60034-30 excludes motors made solely for inverter operation and motors completely integrated into a machine (pump, fan, or compressor) that cannot be tested separately from the machine.
 
SOME 300 MILLION ELECTRIC MOTORS ARE IN USE IN INDUSTRY, INFRASTRUCTURE AND LARGE BUILDINGS AND ROUGHLY 30 MILLION NEW ONES ARE SOLD EACH YEAR FOR INDUSTRIAL PURPOSES


INCREMENTAL ATTENTION
But WEG’s W22 Super Premium Efficiency line of induction motors, featured at SPS Drives, is believed to be the only complete standard range currently available that meets the yet-to-be-ratified IE4 regulations. Design of Premium Efficiency and Super Premium Efficiency Motors needs special knowledge, experience and test facilities, equipped with precision instrumentation. The motors use standard components, rather than exotic materials such as rare-earth magnets. Rather, WEG’s advances are achieved by incremental attention to all the areas in motors where losses occur, such as mechanical losses, stray losses (SLL) and iron losses (Pfe).

The task is to get the efficiency up by minimizing and balancing the single losses, especially those created in the stator coils, the stator iron (magnetising) and the losses within the rotor by slip. In comparison to standard electrical motors compliant to IE1, for IE3 and IE4 motor manufacturing, more iron and copper material are used. IE3 motors are heavier and physically bigger than IE1 motors and typically use higher slot fill in the copper winding, thinner laminations of improved steel properties (reducing the air gap), a better design of cooling fan, and use of special and improved bearings. All of these factors combined, and others, can ensure higher efficiency in the motors. As a result, the motors are also quieter, more reliable, easier to maintain and more cost-effective. Lower operating temperatures contribute to an increase in insulation life and extended service intervals.
 

Key Points

  • Electric motors are the single biggest consumer of electricity worldwide and are a major target area for improving efficiency
  • New energy efficiency standards include IEC 60034-30:2009, a harmonised IE (International Efficiency) grading standard
  • WEG’s W22 Super Premium Efficiency line of induction motors meets the yet-to-be-ratified IE4 regulations
 

 
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