Motor efficiency: aiming high
Control Engineering Europe, October 30, 2017
Brian Bannister argues that it is better for OEMs to build in compliance to electric motor energy efficiency requirements now, to avoid the need for future product redesigns, and to provide customers with immediate energy saving benefits.
New European statutory efficiency requirements for electric motors, which came into force on 1 January this year demands that all AC industrial electric motors from 0.75kW up to 375kW operate within the EU Directive’s specified parameters.
The most common solutions offered to achieve these levels of efficiency are based upon either an IE2 motor with a variable speed drive (VSD) package or a stand-alone, direct on-line IE3 motor. So, compliance should be your first goal. How you achieve it, however, can be dictated by numerous factors. For applications where equipment is driven by motors with powers lower than 0.75kW or above 375kW, there are currently no guidelines or specific requirements.
IE1 efficiency motors can still be used in the EU if they are currently held in stock by equipment/machine manufacturers. However, motor manufacturers cannot continue producing them for customers within the EU, but they can still supply regions outside Europe and countries where the same levels of efficiency are not demanded.
IE4 and IE5 motors
High performance permanent magnet IE4 and IE5 motors might be considered by some as ‘over the top’ solutions, but they do offer immediate and future benefits for both OEMs and end users.
An obvious benefit is compliance for the foreseeable future. Consequently, design engineers can develop equipment with confidence, knowing which motors they can incorporate in their designs to achieve specific performance characteristics, while not having to dramatically change machines from a weight and size point of view. Some IE4 and IE5 motors can offer up 50% savings in weight and can offer size reductions of up to two frame sizes.
When making decisions about compliance – in addition to meeting the required efficiency standard – the issue of payback on investment should be considered. It is estimated that an IE3 motor carries around a 20% premium over an IE2 alternative, but energy savings due to the higher efficiency make it possible to achieve payback in less than two years.
In the future IE4 and then IE5 motors will start to become obligatory. So it is worth adopting the higher efficiency motors today to start to reap the benefits of greater savings on energy now. Certainly, this might be the case if VSDs are already being used because both IE4 and IE5 permanent magnet motors require them.
While compliance is obligatory, essentially it is down to the OEMs and their customers to police this.
According to DEFRA’s Environmental Reporting Guidelines June 2013: ‘The Companies Act 2006 (Strategic Report and Directors’ Reports) Regulations 2013 requires quoted companies to report on greenhouse gas (GHG) emissions for which they are responsible. Quoted companies, as defined by the Companies Act 2006, are responsible to report on environmental matters to the extent it is necessary for an understanding of the company’s business within the Annual Report, including where appropriate the use of key performance indicators (KPIs). If the Annual report does not contain this information, then it must point out the omissions.’
Some public bodies are required to, or should consider reporting GHG emissions. To fulfil these reporting requirements, companies need to monitor and control both their own emissions and those of their suppliers. This will help them to measure the impact of the suppliers’ operations upon their own emissions and include them in their calculations. Smaller companies are, therefore, also being encouraged to achieve similar GHG emission reduction goals.
It would appear that purchasers of electric motors must determine whether motors supplied comply with the appropriate standards as part of the monitoring process to achieve and maintain compliance.
It is still permissible to use and supply >0.75kW IE2 motors provided they are used with a variable speed drive, if they were placed on the market prior to 1st January 2017, or if they comply with one of the many other rules currently in force (there are exclusions applicable to brake motors, integrated motors and motors specified for intermittent duty).
But how this might reflect on you and your products is also worth considering. It may briefly be cost beneficial to stick with the technology but it will impact on the end users on-going efficiencies and GHG emissions.
Surely, it would be better to build in compliance with future known requirements today in order to avoid later product redesigns and associated price increases.
Brian Bannister is a motor specialist at Lafert Electric Motors