Abstract: The invention concerns a method to reproduce and display the winding temperature of an electric power transformer by deriving the measured and displayed temperature from the temperature of the coolant cooling the power transformer and the temperature of an electric heater fed with a current proportional to the load of the power transformer. A thermometer system is used for measuring the temperature and comprises of a hollow sensor element (7) and a mechanical transducer (2) connected through a capillary tube (6) with said element (7) to actuate a mechanical display and comprising several switches, the mutually connected cavities of sensor element (7), capillary tube (6) and transducer (2) subtending a closed pressure chamber filled with a test medium of which the pressure changes in relation to pressure.

Abstract: In the thermometer of the present invention a hollow sensing element (9) is connected by a capillary tube (18) to the hollow space of a Bourdon spring (19). The hollow sensing element (9), the capillary tube (18) and the mechanical measuring unit are filled with a substance whose pressure varies with temperature thus causing the Bourdon spring (19) to actuate a mechanical indicating device (5, 6). The capillary tube (18) or the hollow space of the mechanical measuring unit (2) has connected thereto an electric measuring unit (3) which comprises a measuring chamber (15) enclosed by a rigid casing (12), an electric pressure measuring cell (16) bounding the measuring chamber (16), and an electric measuring transducer (4) connected to the pressure measuring cell (16) for generating a transmittable signal.

Abstract: The invention concerns a filling level measuring device composed of a nonmagnetic slide tube (7) containing a switch (8) driven magnetically in contactless manner and mounted on a plate (1) sealing a container aperture, further of a float (23) displaceably resting on the slide tube (7) and fitted with a first permanent magnet (24) actuating the switch (8). The float (23) of this invention further includes a second permanent magnet (25) a distance from the permanent magnet (24) associated to the switch (8), this second permanent magnet (25) resting by its own magnetic field on the magnetic field of an oppositely polarized permanent magnet (15) affixed to the slide tube (7). A magnetic coil (17) is affixed to the slide tube (7) which when energized generates a magnetic field reinforcing the effect of the oppositely polarized magnetic field and is of such field intensity that the float (23) is lifted into the switching position without being supported by buoyancy.

Abstract: The invention is directed to a liquid level sensing device having a float (4) configured as a hollow body and slidably mounted on a slide tube (3) for the actuation of reed-type switches (11) provided in the interior of the slide tube (3). In order to perform a check for proper functioning, the float (4) is movable independently of the filling level into a signalling position by an electromagnetic actuation device (15). The hollow space (7) of the float (4) contains a gas pressurized to above or below atmospheric and is connected via a flexible tube (12) to a pressure monitoring device (13) which responds whenever the gas pressure deviates from a predetermined value.