VARIATION OF LOSS PER CYCLE WITH PAUSE TIME AT THE MAXIMUM FLUX-DENSITY IN ELECTRICAL IRON SHEETS

Power losses of electrical iron sheets have been measured under controlled magnetizing conditions in which a waveform of magnetic flux density was controlled to be trapezoidal and symmetrical. Magnetizing frequency was varied from 200 Hz to 50 Hz by varying the time duration of the maximum flux density from 0 to 7.5 msec while keeping the time for flux change at 2.5 msec. The result shows that losses per magnetizing cycle increase with the duration of waste time at the maximum flux density and that this increase of losses may be attributed to several magnetic relaxation phenomena and reversal of magnetizing direction.