In the run up to the introduction of the USA's Energy Independence and Security Act (EISA) regulations in December 2010 - which have been echoed in Canada in January - my company received many calls from machinery OEMs, to see if their particular equipment is going to be affected, and to discuss replacement motors.
A few were shocked to find that upgrading to EISA-grade efficiency - which must meet NEMA Premium ratings (equivalent to IEC 'IE3' efficiency in the EU) might require some considerable engineering effort.
There is not room here to detail all of EISA's requirements, but in summary it's much broader in scope than the USA's previous EPact efficiency law, which covered general purpose motors up to 200 HP. EISA now covers new motors from 1 to 500 HP. Baldor publishes a useful FAQ primer on what EISA is - details below.
To ensure a smooth transition to higher efficiency, an understanding of the mechanical and performance differences of these motors is essential in order to realise maximum financial benefits and a trouble-free installation. Energy savings are not the only benefits to premium efficient motors, many other benefits are apparent to the end user.
Transitioning considerations apply to the following main areas:
Mechanical differences. Higher efficiency motors can be larger physically due to the extra material, particularly at the low end of the power range. They will have a smaller fan due to the cooler operating temperatures and therefore reduced acoustic noise levels. Overall a premium efficient motor will operate cooler internally with better steel, quieter, less mechanical stresses through tighter fits and better balancing. This will result in providing a more reliable, longer life-cycle motor installation. Improved productivity from less down time is an additional benefit to a change out to higher efficiency motors.
Electrical power requirements. Using a premium efficient motor will reduce the full load current drawn from the power supply. Therefore the electrical protection of the motor must be reviewed. Conversely, the starting current (or inrush current) will usually increase from 4-5 times full load for a normal efficiency motor, to 6-8 times full load for premium efficient motors. Therefore, the motor overload protection system will also need to be reviewed.
Installation and application. Checking the motor for oversizing is always recommended as changing to high efficiency offers the chance to optimize motor size. Higher efficiency motors operate at higher RPM for the same load and this can cause problems with the driven load, particularly fans, pumps and other quadratic type loads. Starting torque on higher efficiency motors can be less, therefore a check is needed against the characteristics of the driven load. Under loading the motor does not improve efficiency. This may have been true with older, less efficient designs, but higher efficient motors will typically have the best power factor and efficiency at near full load.
Sometimes, such transitioning issues can be resolved very quickly. In other cases, you might need up to three months or more to work through these changes, so be sure to start thinking about EISA as early as possible!
EISA know-how
If you have to look into EISA, then the know-how gained could be of considerable general value to your company. Similar minimum efficiency legislation came into force in the EU in June 2011. It mandates a minimum efficiency level of IE2 for new general-purpose AC motors. IE2 is a lower level of efficiency than IE3 (the equivalent to NEMA Premium under EISA) - which the EU will mandate from 2015 (see Table).
The differences between our continents poses an important question for OEMs. American manufacturers will already have developed IE3-rated high efficiency versions of their machinery. In some cases, especially where the motor represents only a small portion of total equipment cost, it may be the case that they offer their standard IE3-rated version to the world market. Most end users of automation are becoming seriously worried about their energy costs. Many are also currently putting strong environmental care plans into place. Given this market situation, it could be that those companies that start to offer the best efficiency levels available could see their market share grow at the expense of those who merely offer the minimum required.
Baldor is suggesting that European OEMs can usefully pose the question "Should we start offering IE3 efficiency now, even though it is not required by law until 2015?". If they don't consider this issue, their North American-based competitors might steal a march.l
Enter √ or at www.engineerlive.com/ede
Robin Cowley is Sales Manager - Western EU, Baldor UK Ltd, Bristol, UK. www.baldor.co.uk. Baldor's guide to EISA (Energy Independence and Security Act) can be downloaded from: www.baldor.com/support/literature_load.asp?LitNumber=IMS501DE
