New Magnetic Core Loss Comparator

Abstract

A new method has been developed for the rapid measurement of magnetic flux density and power loss in single sheet steel specimens. In use the sheet specimen is inserted into an exciting unit which generates an ac magnetomotive force to provide the required flux density. A measuring head is then pressed against the surface of the specimen and the power loss and flux density are read directly on an indicating instrument. Localized measurements in areas as small as 1 sq in. are possible. Simultaneous pickup of the emf induced in the specimen by the time varying flux, and the mmf generated by the exciting unit is accomplished by a pair of probes and a modified Chattock coil. Specially designed amplifiers, integrating circuits and switching arrangements enable the operator to observe the hysteresis loop or to read the power loss directly. Specimens of varying shapes and sizes may be employed without cutting or stacking and power loss distributions are readily observed.