Theory of an improved thermomagnetic generator

Heat energy may be used directly to produce electrical work in devices having no moving parts, by employing the properties of ferromagnetic substances near their Curie points. While thermomagnetic generators proposed in the past had poor theoretical efficiencies, the study discloses an improved generator having a circuit arrangement which allows the load current to assist in obtaining a better thermodynamic path. By resonating the current in the load circuit, the generator produces sufficient self modulation of the field to allow the improved thermodynamic cycle to be achieved in a very simple manner. Expressions are derived by thermodynamic and electrical analyses for current, voltage, field quantities, cyclical work and heat addition and efficiency. The specific power, which was proportional to the square of the magnetisation change in previous generators, is now proportional to the product of the applied field and the first power of the magnetisation change. This leads to devices whose performance in ordinary applied magnetic fields is conservatively doubled, while in the high-intensity magnetic fields of superconductors there is more than an order of magnitude improvement in performance.