Modern magnetic testing equipment for electrical steels

Computerized magnetic testing equipment is described which was designed and built at the Research Center of Armco Inc., and is employed in the Magnetic Testing Laboratory at Armco´s Butler Works to perform the 60 hertz magnetic tests required for the grading of electrical steel. First, an overview of the tests required for grading electrical steel is presented. Then, analog circuitry used for supplying test power and for measurement of specific core loss and other variables in these automatic consoles is discussed, including the waveform control feedback which maintains sinusoidal flux in the test specimen and test power control loop which sets induction or magnetizing force. Finally, the role of the integral microcomputer in the new consoles is discussed. This microcomputer collects information concerning the test specimen from several sources, controls testing of the specimen using this information, produces a printed report of the test results, and sends those data to another computer which grades the material.