Magnetically caused dynamical deformations in an induction furnace-comparison between calculation and measurement

The submitted paper describes the calculation of three-dimensional mechanical oscillations of an induction furnace as a result of its operating load. It is a characteristic feature of induction melting apparatus that they have to use high coil currents. Instantly coupled to these currents are the Lorentz-forces within the coils, which contain as a result of the furnace´s harmonic power supply also harmonic parts in their time-dependency. In combination with the Lorentz-forces the surface-forces on the yokes instigate mechanical oscillations of the whole furnace. The harmonic oscillations cause long term fatigue of material. Specifically inside the ceramic coil-isolation they are also responsible for the noisy characteristic of the furnace. The aim of this work is the understanding of the main action principles beginning with the coil current supply and ending with the oscillations of the mechanical structure to achieve some ameliorations through modifications of constructional details. The effectiveness of the method will be proved by measurements