Hall-effect wattmeter for measuring iron losses at high flux densities in a single epstein sample

The paper considers in detail a transistorized synthesizer or harmonic generator. It is driven by a highly stable 400-Hz reed oscillator, binary divided, which controls the master square-wave generator at 50 Hz. Each harmonic channel consists of two selective amplifier modules separated by a limiter and has amplitude and phase control. A complex wave is formed of harmonics up to and including the forty-ninth. This is fed to a 1-kVA power amplifier via an adding stage. Connected to the output of the amplifier is an excitation coil containing the single Epstein sample under test. On the sample is wound a -search coil whose waveform is made sinusoidal. The Hall plate is positioned in the center of the excitation coil perpendicular to the air flux. The coil is connected to the Hall plate buffered by an amplifier. The current through the Hall plate is proportional to the induced voltage, Hence the output from the Hall plate is a measure of the iron losses of the sample. Losses have been measured up to 24 kG for sinusoidal flux density and at several frequencies using the harmonics as fundamentals.