Cooler, more compact and cost-efficient: construction know how for IE2 and IE3 energy saving motors

NORD Drivesystems has implemented a 3 point concept for its new energy saving motors which meet the globally applicable requirements of the new IEC standard 60034-30. Compliance with the IE2 efficiency class is achieved by the use of more active material, secondly by selecting high quality sheet metal with less losses, and thirdly with increased copper filling factors in combination with a simultaneous reduction in the size of the winding heads through an optimized production process.

NORD Drivesystems has implemented a 3 point concept for its new energy-saving motors which fulfill the globally applicable requirements of the new IEC standard 60034-30. Compliance with the IE2 efficiency class is achieved firstly by the use of more active material, secondly by choosing higher quality sheet metal with less losses, and thirdly with increased copper filling factors in combination with a simultaneous reduction in the size of the winding heads through an optimized production process.

NORD IE2 motors have been available for several months. They offer various advantages, including improved efficiency, higher start-up and breakdown torques, decreased slip, and better thermal performance. Compared to their direct predecessor models, IE2 type motors offer an increased service life and help save operating costs. If required, the operating range, which has been shifted upwards towards a better efficiency, can be used to continuously operate the new motors at a 150% performance factor. Alternatively, users can utilize a smaller motor type for many applications.

NORD is also currently developing IE3 motors, which will be introduced in the USA in late 2010. The IE3 motors will be at least 10% more than the IE2 class motors. The increased efficiency will be achieved by replacing aluminum with copper as the conductor material for the squirrel cage, which considerably reduces rotor losses in IE3 systems. The slip under load will also significantly decreased compared with aluminum motors. The torque curve in the operating region is considerably steeper. The breakdown torque is attained with a lower slip. In addition, the starting torque, which is proportional to the rotor losses, is significantly lower. Unlike aluminum motors, IE3 motors with a copper rotor do not require an increased amount of iron or need merely a moderate increase. In addition to using alternative materials such as copper, other measures include the use of sheet lamination material with lower specific core losses, and larger conductor cross-sections in the windings. These flux-optimized windings will then have smaller winding heads. Further increases in efficiency can also be achieved with permanent magnet motors and with frequency inverter operation (synchronous motor principle).