Hysteresis effects with varying superposed magnetizing forces

THE hysteresis effects discussed in this paper occur when magnetic fields are produced in iron by electrical circuits carrying simultaneously currents of different frequencies. Investigations have shown that when two currents of different frequencies are so superposed, the losses in the iron corresponding to each frequency may differ greatly from those obtained when each frequency is acting alone in the circuit. These effects are, therefore, particularly important in the electrical communication field because of the practise of transmitting over one circuit currents of different frequencies. Predictions of the behavior of iron-cored inductance coils and transformers in such a circuit may be erroneous if based on measurements of the iron losses which have been made in the usual way with single-frequency test currents.