Loss prediction in electrical steel laminations and motor cores

There is a growing demand to predict iron losses in laminations or in magnetic cores more accurately. Losses can be predicted in laminations under known magnetising conditions using Preisach or other methods with accuracy to within 5% of measured values being claimed. The state of magnetisation is far more complex in motor or transformer cores and empirical prediction becomes impossible due to effects of temperature, mechanical stress and other building dependent parameters. This review summarises the loss mechanisms and means of analysis before showing practical results of loss prediction using different approaches applied to single laminations or machine cores. It is demonstrated that good progress has been made over the past few years and that it is now becoming feasible to predict machine core losses with accuracy better that +/- 3%.