The efficiency of variable speed drives with induction motors and permanent magnet synchronous motors has received little attention so far in international standards. However the number of such applications is increasing rapidly and the potential energy savings are large. This paper is based on a measurement campaign of three collaborating research institutes and reports on the efficiency of motors up to 15 kW. The efficiency values are represented by means of iso efficiency contours. From these contours, the efficiency for IE1, IE2 and IE3 induction motors is compared with that of a permanent magnet machine for the entire torque -speed operation region. Also the impact of flux optimization with induction motors is analyzed. The required number of measurement points to construct accurate iso efficiency contours with minimum measurement effort is also discussed.

Increasing awareness of ecological problems forces machine manufacturers to design greener machines. This implies amongst other things the selection of the most efficient electric motor system for their specific application. On the other hand, machine building applications evolve more and more from constant speed and load characteristics to varying speed and load applications. Therefore, the motor system that is used evolves more and more from direct online (DOL) to motors fed by a variable speed drive (VSD). However, current efficiency standardization focuses on DOL applications, and can by consequence not offer assistance to the machine builder to select the most efficient motor-VSD combination for his particular varying load application. The goal of this paper is to present a methodology that allows to predict the energy consumption for a specific motor-VSD combination and a specific varying speed-load application, using the fairly new concept of iso efficiency contours. By comparing the predicted energy consumption for a number of selected combinations, the most efficient one is revealed.

Φ Abstract --Despite recent revisions and harmonization efforts of international motor efficiency standards which has lead to the revised IEC Std 60034-2-1 and the efficiency classification of IEC Std 60034-30, there remains a lacuna in the context of motor systems efficiency. Although IEC is preparing a "Guide for the selection and application of energyefficient motors including variable-speed applications" labeled IEC Std 60034-31, to date, there is no internationally accepted test protocol that allows the determination of drive system efficiency at different load points. As the first in a set of three by a joint research project of three research institutes, this paper introduces iso efficiency contours as a useful tool in this context. The concept of these contours as well as their mutual interaction with system specifications and losses are discussed. A first testing protocol for all types of motor drives is proposed. The concept is illustrated by first results of an extensive testing campaign.

Abstract-Over the last decade, forced regulations and a growing social awareness with respect to energy efficiency have resulted in a renewed interest in the research for high efficient electrical machines. When an electrical motor is coupled to a machine, in many cases a gearbox or belt transmission is used.Research shows a lack of information on energy efficiency of these components. In comparison to electrical motors and drives, there is very few regulation and if efficiency values can be found in catalogues, there is no regulated test procedure available to validate the data. As a result, the reliability of these efficiency values is unknown and comparison between manufacturers and technologies is impossible. In this paper a test bench is proposed to measure the energy efficiency of a gearbox with an accuracy up to 0.4%. The test bench is used to measure the efficiency of gearboxes in their entire speed and torque range. Contour maps are used to visualize these measurement results. Moreover, a measurement campaign using different gearboxes is carried out to compare the energy efficiency in the manufacturers catalogue and the measured efficiency.

A calorimeter test bench for the efficiency and power loss determination of power electronic variable speed drives is presented. The balanced calorimetric setup with air as the cooling medium is proposed to test small electronic drives for AC motors in a power range from 1 kW up to 7,5 kW. The construction, the required measurement equipment, the measurement procedure and especially the measurement results and uncertainty are important aspects of this test bench and are discussed in this paper. The device under test is a 2,2kW drive which is measured using both the input-output method and the calorimetric method. The test results are compared and conclusions are made concerning usability, repeatability and accuracy of the test bench. The overall goal is to further examine and optimize the calorimetric approach and to be able to obtain more accurate and comparable test results of very high efficient frequency converters. This setup reaches an uncertainty of ±2,39% or ±1,48W on the power loss at full load and speed using the calorimetric method.