Energy–Efficient Motor Design – One Trend, Different Approaches
High Performance, Low Energy Consumption
The efficiency scale for 2, 4 and 6 pole low-voltage electric motors is one key metric. Three energy efficiency categories have been defined, namely IE1, IE2 and IE3 (IE4 is on the way soon and there is already talk of IE5 motors). The motor regulation (EC640/2009) applies to nearly all motors rated between 0.75 kW and 375 kW as follows:
- Stage 1: as of June 16th 2011 all motors must be IE2-compliant.
- Stage 2: from January 1st 2015, all electric motors rated between 7.5 kW and 375 kW must be either IE3-compliant or IE2-compliant and have a frequency converter.
- Stage 3: from 2017, all electric motors rated between 0.75 kW and 375 kW must be either IE3-compliant or IE2-compliant and have a frequency converter.
This regulation applies only to the European market. However Australia, China, Brazil and Canada have introduced similar energy efficiency regulations. In the US, the NEMA Premium standard (equivalent to efficiency level IE3) has been in effect since the end of 2010.
Some Motors Already Exceed Standards
Ingo Landwehr from Grundfos reported that many manufacturers are skipping Stage 1 and are incorporating the 2015 standard into their designs: “IE3 motors or IE2 motors with frequency converters are already the standard at our company.” He highlighted the differences in functionality. “The frequency converter and the controller are built into our Blueflux MGE motors rated at up to 22 kW (IE3). This translates to lower cost for commissioning (cabling, matching the pump and the frequency converter) and operation, particularly in variable-load applications.” The list of optional features includes the capability to monitor bearing temperature and communicate with higher-level systems.