Currently the IE classification applies only to motors, but the new standard takes a broader approach to all drives (VSD) and drive-motor packages. Traditional IE classifications focused solely on motor efficiency under rated conditions. However, real industrial applications rarely operate continuously at nominal load and speed. Especially in pump and fan systems, partial load operation dominates daily usage profiles. The EN 50598-2 methodology evaluates efficiency not only at full load but across defined operating points, considering both motor and converter losses. This approach reflects real-life duty cycles more accurately and provides a system-based efficiency perspective rather than a component-based assumption.
Why is this standard important?
The introduction of CDM (Complete Drive Module) efficiency classes acknowledges that variable speed drives introduce additional switching and conduction losses. Power electronic components such as IGBTs and rectifier stages generate heat during operation, and these losses vary depending on switching frequency and load conditions. By standardizing how these losses are measured and reported, the new classification enables transparent comparison between different drive technologies. This prevents misleading efficiency claims based only on motor nameplate data.
Because engines consume 28% of electrical energy worldwide. Most pump and fan applications are sized above nominal to meet the maximum demand of the system. Variable torque applications generally follow the cube law, meaning power demand is proportional to the cube of speed. So a small increase in speed requires much more power, but a moderate decrease in speed can save large energy. Modern smart motor control methods can play an important role in improving energy efficiency.
A Logical Approach
System-level evaluation is particularly valuable in variable torque applications governed by the affinity laws. Since power is proportional to the cube of speed, even minor speed reductions can dramatically decrease energy consumption. Under the EN 50598-2 framework, engineers can quantify these savings more precisely by analyzing the complete Power Drive System (PDS) rather than estimating separate motor and drive efficiencies. This allows better lifecycle cost analysis and more accurate return-on-investment calculations for retrofit projects.
Major manufacturers such as ABB strongly support the new standard. When implemented correctly, EN50598-2 will help OEMs and industrial users achieve better operational efficiency across entire systems, not just individual components. The new standard and the IE classifications it includes may surprise you a bit, but don’t worry: You’re not alone. The standard is not easy to understand, but this article will help you and explain how ABB expertise can provide clear and valid comparisons on overall efficiency.
Brief Description of EN50598-2
The EN50598-2 standard defines new IE classes for the drive module (CDM) and new IES classes for the driven system (PDS). This standard applies to motors and drives in the voltage range from 100 to 1000 V and the power range up to 1000 kW.
For years, Direct-on-Line (DOL) engines had classifications of IE0, IE1, IE2, IE3 and IE4. As the number increases, the efficiency also increases. The new EN50598 standard introduces the new term CDM (Driver Module), which is the same as the old term driver (VSD). CDM currently has IE classes IE0, IE1 and IE2, but these IE classes are defined differently than DOL engines.
The new EN50598 also defines for the first time the term PDS (Driven System) which equals the total system efficiency even taking into account losses. PDS is a combination of engine and VSD and is rated with the new IES classes IES0, IES1 and IES2.
Like a Pump Curve for the System
Industrial process operators already know the working conditions and operational points. Equipped with this process knowledge and better data for the combined drive-motor power efficiency that the new standard will produce, it is easier to evaluate efficiency and power losses. For example, in a pump application, by knowing the operating ranges, engineers can more accurately calculate losses in the entire motor-drive-pump system. This is similar to a pump curve where the performance of a particular piece of equipment is well defined; but now the motor-driver-pump data are combined. This gives a much more accurate indication of what the efficiency of the system will be, rather than using assumptions about how various components will interact.
Now customers will clearly document this data according to the EN50598-2 standard. This will streamline business operations by supporting both OEMs and industrial operations with classification and reporting. It will also help prioritize where energy-saving investments should be made to increase the operation’s return on investment. Since ABB is both a drive and motor manufacturer, it can calculate and verify IES values for the entire system.
Modern Drivers Can Monitor, Optimize and Report
Manufacturers capable of supplying both motors and drives have a significant advantage in determining verified IES values. Because the motor and drive are tested and characterized together, interaction losses can be measured directly instead of calculated theoretically. This integrated validation ensures compliance with EN 50598-2 while providing reliable documentation for energy audits and regulatory reporting. For industrial facilities aiming to reduce operational expenditure and carbon footprint, system-based classification becomes a strategic tool rather than just a regulatory requirement.
Today’s smart drives play a critical role in these systems by monitoring, optimizing, reporting energy consumption and ensuring that the least amount of energy is used to start the engine. ABB’s standard drive ACS580 is designed to both save energy and meet the reporting definitions of the new standard. It meets the highest IE2 drive energy efficiency class and includes advanced energy efficiency analyzers and energy optimization functions. ACS580 drives support energy-efficient motor types manufactured by ABB, including asynchronous motors, permanent magnet motors and high-efficiency IE4 motors. Numerous intelligent functions built into the drive bring great benefits to users. For example, energy optimization features provide maximum torque per ampere in both scalar and vector control modes, reducing the energy drawn from the source and providing additional energy savings of up to 10% even at partial loads. It is also easy to create accurate reports on hourly and daily energy consumption as well as aggregated information. For both financial and environmental audits, the driver can calculate financial savings and reduced CO2 emissions if previous direct online (DOL) power consumption data is given as a comparison point. The resulting data also makes it easier to predict the driver’s return on investment.
Achieving superior energy efficiency is a work in progress, and ABB’s lifecycle services are built to ensure processes run efficiently year after year. This means complete services are offered, from sizing and commissioning to replacement with a more efficient drive at end of life. The result is sustained efficiency gains and savings in both energy and operating costs.