Abstract: An electrical component such as a transformer winding or choke coil is placed in a forced cooling circuit containing circulation pumps and coolers for a cooling medium and is subjected to forced circulation cooling. The thermal monitoring apparatus comprises a container housing therein a thermal sensor surrounded by a thermosensor winding. The container is connected by respective branch lines to the forced cooling circuit either upstream or downstream with respect to the circulation pumps. Cooling medium flows through the transformer or choke coil in the forced cooling circuit and through the branch lines leading to the container. Each branch line is provided with an equivalent hydraulic resistance of the transformer winding and the cooler. The thermosensor winding is connected to a current transformer which is supplied with a current which is proportional to the current flowing through the transformer or choke coil.

Abstract: The present invention provides a process for maintaining magnesium-containing cast iron melts in a castable state for comparatively long periods of time of, for example, several hours or days, with the use of a protective gas atmosphere, wherein the protective gas atmosphere present above the surface of the melt, as well as all the adjacent parts of the apparatus used, is kept at a temperature above the boiling point of magnesium, i.e. 1102.degree. C., and always has a partial pressure of magnesium vapor which is the same as or greater than the vapor pressure of the magnesium within the melt.