The large capacity switching gear indicated in the figure produces electrodynamic repulsion force by the current flowing in the contacts during excitation. Therefore, the contact stress needs to be larger than the electrodynamic repulsion force produced by the maximum excitation current. This example presents the use of a magnetic field analysis to obtain the electrodynamic repulsion force of a switching gear from the Lorentz force when a short-circuit current of 100 kA is applied.
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