Premium efficiency motors effectiveness

The paper presents an experimental comparison of the efficiency performances of 3 hp Premium efficiency induction motors issued from three different main manufacturers. In general, the obtained experimental results concord sensibly well with the rated nameplate data. In the rated regime, the three motors show faithfully the same efficiency, but a certain 1 to 2.5 % discrepancy appears with load and frequency variations. Furthermore a comparison at different operating voltages shows that, under the same load conditions, the Premium motor operates with up to 2 % lower efficiency when supplied from 208 V voltage source rather than 230 V motor rated value. The experimental results show that feeding voltage has an important impact on efficiency value, while efficiency at low frequencies depends on a certain level of manufacturer technology. From a global energy saving point of view, the ASD application to Premium efficiency motors should be promoted just when adjustable speed is needed.