| With the rapid development of the construction of the power industry,as a manufacturing material for various types of transformers,large,medium and small motors,home appliances,generators,etc.,the performance of electrical steel has attracted much attention.The magnetic performance testing of electrical steel has become the focus of research.The magnetic properties of electrical steel The detection gradually develops towards the direction of high stability and high accuracy.However,at the current stage of electrical steel magnetic performance measurement technology,there are problems such as non-standard air magnetic flux compensation,environmental temperature affecting the measurement results,and non-standard calibration of the electrical steel magnetic performance measurement system.Therefore,the research on the measurement of magnetic properties of electrical steel is of great significance.This article is based on the principle of measuring the magnetic properties of electrical steel by the Epstein square ring method,and according to the national standard GB/T 3655-2008 "Method of measuring the magnetic properties of electrical steel sheets(bands)with the Epstein square ring".The measurement method of the coil method uses TD8510,TD8520,TD8550,TH2100 and other electrical steel magnetic performance measurement systems to conduct experimental research on the air flux compensation,temperature effect,and magnetic performance measurement system calibration methods of the Epstein square loop method.First of all,the feasibility of an air-core coil as an air flux compensation device was verified through experiments.After compensation,the voltage at the end of the induction coil is less than 0.1% of the voltage of the induction coil itself,which is in line with GB/T 3655-200 for the air of Epstein The requirements of the magnetic flux compensation effect;studied the effect of the compensation coil placed at different positions on the air flux compensation effect,and found that the compensation effect is the best when placed in the center of the square ring frame;The effect of has been theoretically verified,and the measured total loss after compensation is higher than that without compensation.Secondly,through experiments,it was found that the specific loss of electrical steel samples decreased non-linearly with temperature in the temperature range of5 ℃ ～ 45 ℃,which provided a reference basis for the measurement of total loss of electrical steel at different temperatures in normal non-constant laboratory;The mathematical tool of least squares fitting is used to fit the specific total loss of different grades of electrical steel samples at different magnetic induction points with the change of ambient temperature to obtain the fitting expression and the fitting formula.In the calculation,the error between the calculated value of the non-fitting point and the actual measured value is less than 0.5%.Finally,the calibration effect of the standard sample calibration method was tested,and it was found that the standard sample method did not have universal applicability to different grades of electrical steel samples.After using the standard sample correction factor to correct the instrument,the sample of the non-standard sample brand number was higher than the total The loss error is increased by an average of 1%～1.5%,and the maximum relative error after correction of the mean square error of the error is 146.91% before the correction;a standard table calibration method based on a high-precision electric meter is proposed,and a correction formula for the calibration coefficient is obtained by experiment The effectiveness of this method is verified,and the maximum relative error is 35.64% after correction of the mean square error of the error. |
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