Effect of Cold Crucible Shape on Levitation Force Working to Solid Metallic Ball

Abstract

An experimental device which enables to measure the electromagnetic force working toward the metallic ball in the cold crucible was invented to obtain the basic data on the installation and the operation for the optimum levitation melting. The levitation force at the arbitrary position of metallic ball could be measured directly under supplying the electric power. By this device, levitation forces were measured using balls made of different kind of metals under various shapes of cold crucibles. The results obtained are as follows.
(1) Levitation forces depended upon the electric resistivity of metallic ball. Low resistivity metals such as copper could be levitated easily but ferromagnetic substance such as iron could not be levitated below Curie temperature.
(2) Levitation forces varied considerably with metallic ball position and coil position, and these behavior were influenced by the number of slits that regulated both magnetic flux and eddy current.