Abstract: A method of monitoring oil level in a transmission system of a machine is disclosed. The method includes monitoring an oil pressure and calculating an average value of the oil pressure over a first predetermined time duration. The method further includes calculating a variance of the oil pressure from the average value and recording a deviation if the variance is beyond a threshold variance. The method further includes detecting a low oil level condition if a count of deviations is above a threshold count within a second predetermined time duration.

Abstract: A PTC resistive strip is mounted on a wall of a washer tub. Water in the tub carries away heat from the energized strip thereby reducing its resistance. The water level in the tub is measured by measuring the voltage drop across the strip. The resistance of the strip can be compared to the resistance across a variable resistance or resistor to indicate that the water has reached a desired level. A comparator output can be used to control the water level and washer motor operation via a control circuit which operates the water supply valves and motor switch. A second PTC resistive element is also provided for sensing overfill.

Abstract: A PTC-resistor which is a temperature dependent electrical thermistor of semiconductor ferro-electric ceramic which is provided with power leads and serves as a sensor element is directly fused into glass. The power leads are welded to metal coatings formed on the PTC-resistor which are stable at the temperature occurring when the PTC-resistor is fused. The metal coatings are made of aluminum which are formed by aluminum silk screened metallizations which have a thickness of 50 .mu.m or more.

Abstract: A detection element including a cylindrical base body, an electric resistor formed on an outer peripheral surface of the base body, and lead wires attached to ends of the base body. The lead wires are electrically connected to the electric resistor. An electrically thick film is provided over end faces of the base body, an inner peripheral surface and an outer peripheral surface of the base body near each of the opposite ends of the base body, and the lead wires are electrically connected to the resistor at least through the electrically conductive thick film.

Abstract: Detection of events, e.g. liquid leaks and other changes in varibles. The event causes two conductors to become electrically connected, and thus creating a system in which the connection point can be located by measuring the potential drop from one end of one of the conductors (called the locating member) to the connection point. Preferably a fixed current flows through the connection, so that the result is independent of the resistance of the connection. The locating member can be a continuous resistive wire, preferably coated with a conductive polymer; such a locating member can form part of a sensor cable in which the elongate components of the circuit are in a wrapped configuration, or part of a cable in which the conductors are separated by a member shaped to prevent capillary action of a liquid from connecting the conductors. Alternatively the locating member comprises a plurality of discrete resistors.

Abstract: An output controller for low-frequency treatment device for use in a bath, comprising a low-frequency oscillator; a variable water resistor having fixed terminals connected with the output terminal of the low-frequency oscillator; and an active electrode connected with the sliding terminal of the variable water resistor.

Abstract: A level measuring probe for a liquid contained in a reservoir of the type having a detecting element constituted by a conductor having a high temperature coefficient and intended to be immersed in the liquid; and an electrical connection means intended to permit connection of the said detector element to a connector; a plurality of printed circuits disposed in respective parallel strips are provided on an insulating substrate, the assembly forming a flexible film and each circuit having a detecting zone and an electrical connection zone; the film is assembled to a support of, for example, stainless steel; the assembly is out at the edges of the parallel strips.

Abstract: A system for actuating a warning device when the level of a liquid in a receptacle is below a preselected level. This system includes a probe formed from a length of positive temperature coefficient wire whereby the resistance through the wire increases with increased temperature. This wire is mounted within the receptacle in a manner that allows the wire to be submerged in the liquid under normal conditions. A detection can be made when such wire is partially or completely out of the liquid. There is a first switching device in the system to apply a voltage across the wire and a detector for actuating the warning device in response to an electrical characteristic of the wire as determined at a preselected control point in the circuit including the probe. In accordance with the preferred embodiment, the detector includes a capacitor and a second switching device to ground the capacitor for a preselected time and then use the charged capacitor to follow the voltage of the probe.

Abstract: A conductivity sensor for use in a steam turbine in operation to monitor corrodents being deposited therein. The sensor comprises a bottom substrate on which an electrode pair is located. The bottom substrate also includes a means for measuring the temperature at the bottom substrate. A first layer of dielectric material is bonded to the top of the bottom substrate. The first layer has an aperture formed therein so that an end of the electrode pair is located in the aperture. A second layer of dielectric material is bonded to the top of the first layer. The second layer defines a crevice for entrapping steam-transported corrodents that are deposited in the turbine. A portion of the bottom of the crevice includes the aperture so that corrodents are also deposited in the aperture. By passing a current between the ends of the electrodes located in the aperture, a measure of the conductivity and thus the concentration of corrodents deposited in the aperture and crevice is given.