The European Union has made clear its ambition to tackle global climate change through its commitment to reduce CO2 emissions. Electricity generation is a large contributor of CO2 emissions and industry is a large consumer of electricity. In the industrial sector, electric motors are the largest consumer of electrical energy. It has prompted the Ecodesign Directive for electric motors legislation which mandates minimum energy efficiency levels. The document is the latest step as part of a long-term plan aiming to reduce greenhouse gas emissions by approximately 100 million tonnes per year by 2030.
By this month (July 2021), the legal requirement for energy efficiency in variable speed drives will be tightened considerably when the European Commission directive 2019/1781 will become national legislation in all EU member states.
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At OJ Electronics the new directive is seen as a step in the right direction:
“We see the new directive and its focus on energy efficiency as a very positive move – both for us and for the industry as a whole. Ever since we started producing frequency converters, energy efficiency has played a central role in our continuing product development process. Not only because it has a positive impact on the environment, but also because it makes business sense – for the end-users as well as for us. Therefore, greener products through innovation are a mantra written into our mission statement”, says Preben Jessen, Head of Drive Products at OJ Electronics. “Because energy efficiency is our brand, it has been written into the specification of every single product from the beginning, including our drives. Therefore, they have been compliant with even the strictest international standards years before it became a legal requirement,” he explains.
The Tier System
The European Commission directive operates with a three-tier system for drives and five-tier system for motors, which both affect the level of motor power efficiency. Furthermore, the directive operates with a combined solution, which enable the drives to affect the entire level of motor power efficiency.
“Only tier one and two apply to the drives, but if you join an IE2 motor with an IE2 drive, you suddenly have a motor/drive system which complies with the highest IE4 requirements,” Martin A Jensen Test and QA Manager in the Research & Development Department at OJ Electronics explains.
“We are very proud that all drives here at OJ already comply with the IE2 requirements,” says Preben Jessen.
A fundamental concept in the directive is the “comprehensive product approach”, which enables energy optimisation at system level. It measures the power efficiency or loss of the motor system and combines it with the efficiency of the entire driven equipment.
As an example, a fan driven by a motor which is fed by an AC drive would be the “driven equipment”, while the motor and drive together are the “power-drive system”. The drive on its own is called the “complete drive module” (CDM).
The comprehensive product approach makes it possible to determine the efficiency of the entire combined drive + motor + fan system – by combining the efficiency of the drive, motor, and fan.
In this way, it is possible to determine the power efficiency in part-load conditions by breaking down the part-load efficiency into the three elements: drive, motor and fan and determining their respective power efficiency. By knowing the load-time profile of the individual application it is possible to sum up the efficiencies in the individual operating points and subsequently calculate the Energy Efficiency Index – EEI of the system.
In other words: Not only does the directive focus on power efficiency – it also encourages industry transparency, as it demonstrates how customers can use the EEI as an indication of how efficient the individual system is.
“Knowing this, our customers can compare systems and optimise by selecting the most efficient drive for their particular motor,” Preben Jessen explains.
Being able to choose the best possible drives in terms of suitability and energy efficiency will help products across the world become more efficient and there is no doubt that the focus on the environmental impact and seen in the Ecodesign Directive will have a positive impact on energy consumption worldwide.
Power loss data sheets on all our OJ-DV drives can be found here