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: A thermometer for measuring the temperature of at least one selected portion of an electrically-operated device disposed in a container includes a first upwardly extending conduit adapted to communicate interiorly with the container, and an indicating capacitor defining a first chamber communicating with the first conduit. The indicating capacitor includes a first dielectric material, and a first electrically non-conducting liquid having a predetermined coefficient of thermal expansion; the first liquid is adapted to be disposed at least in part in the container, and at least in part in the first chamber and the first conduit, so that at least a portion of the first dielectric material is constituted by a portion of the first liquid. A reference capacitor defines a second chamber, and includes a second dielectric material.