Motor energy-efficiency developments: recycling, efficiency classes
Although an effective date isn’t expected before 2011, mandatory minimum energy performance standards (MEPS) for electric motors are coming to Europe in 2009. This will promote energy-efficient (EE) motor systems that can save up to 30% of the 70% of industrial electricity used by motors, according to Prof. Aníbal T. de Almeida, Electric Engineering Dept., University of Coimbra, Portugal.
At the recent Motor Summit `08 in Zurich, Switzerland, Aníbal T. de Almeida, Electric Engineering Dept., University of Coimbra, Portugal, presented details of a study prompted by the European Union’s Ecodesign Energy-using Products (EuP) directive. This study has spurred mandatory minimum energy performance standards (MEPS) for electric motors, which are coming to Europe in 2009. Control Engineering covered the topic in its February 2008 issue. Here are additional details about the study and some related discussion.
While the range of electric motors affected was 0.75-200 kW (subsequently extended to 375 kW), three specific motor sizes were analyzed in the life-cycle cost (LCC) and environmental impact calculations. These were 1.1 kW, 11 kW, and 110 kW (1.5, 15, and 150 hp), representing small, medium, and large units. An average motor load factor of 60% and various operating time scenarios from 2,000 to 8,000 hours/year were used.
Recycling and replacement
The motors’ bill-of-materials (BoM) received extensive analysis for environmental effects. Included here were insulation materials, impregnation resins, paint, and packaging materials. Replacement of windings and bearings over the long life of motors was considered in the BoM analysis. As much as 95% of metal content in motors can be recycled, which was factored into the LCC analysis.
As for brushless permanent magnet (PM) motors , the statement that they’re readily available only in the lower power range of 0.75-7.5 kW is largely true. However, it should be noted that much larger size brushless PM motors are offered by some U.S. and Japanese manufacturers. (For example, see “
,” October 2008 Control Engineering .)
It’s not a question of technology availability. Today’s higher initial cost for large brushless PM motors limits current sales volumes. Superior efficiency may drive up future demand, which would lower pricing.
Motor efficiency classes
In reference to the new, globally harmonized motor efficiency classes defined in standard, IEC 60034-30, there is a fourth motor class called IE4-super premium efficiency. This “future” motor class has been left open as far as a specific motor technology. One promising candidate might be the brushless PM magnet motor.
Scenario 2 for implementing mandatory MEPS for induction motors in the European Union (see main article) was proposed because it’s more difficult to manufacture high-efficiency motors in smaller frame sizes applicable to the 0.75-7.5 kW power range. This is especially the case for IEC frame sizes and 50 Hz design. The task is difficult but possible as new IEC motors in the market attest.
Also see related articles :
—Frank J. Bartos, P.E., Consulting Editor, Control Engineering
Machine Control eNewsletter