Comparison of standards for determining losses and efficiency of three-phase induction motors

The efficiency of induction motors has emerged as having the biggest potential in saving energy consumption. This is important to South Africa where energy saving has risen as a major concern. This paper looks at the different motor efficiency standards that are available and attempts to compare them. The paper discusses results obtained from tests done on a 3kW high efficient motor. Three standards used were the CSA-390 a Canadian standard, IEEE 112 an American standard and the new European standard, the IEC 61971. Results show that the IEEE and CSA-390 produce higher efficiencies than the IEC standards. The reasons for this are discussed The effects of equipment accuracy and supply harmonics are discussed in brief. A suggestion for a South African Standard with aspects drawn from the standards is put down as the present SANS JEC 60034-2 (1972) is outdated.