Abstract: In order to determine contact erosion of an electromagnetic switching device, a mechanical parameter is measured which characterizes the time course of the relative movement between the contacts, said movement being caused by an actuator. The point in time when the contacts close is determined by evaluating the time course of the relative movement, and the distance traveled by the contact/s until said point in time or the distance traveled by the actuator from said point in time until reaching the final position thereof is detected at least indirectly and is compared to a stored reference value.

Abstract: Quantum well thermoelectric modules and a low-cost method of mass producing the modules. The devices are comprised of n-legs and p-legs, each leg being comprised of layers of quantum well material in the form of very thin alternating layers. In the n-legs the alternating layers are layers of n-type semiconductor material and electrical insulating material. In the p-legs the alternating layers are layers of p-type semiconductor material and electrical insulating material. In preferred embodiments the layers, referred to as superlattice layers are about 4 nm to 20 nm thick. The layers of quantum well material is separated by much larger layers of thermal and electrical insulating material such that the volume of insulating material in each leg is at least 20 times larger than the volume of quantum well material.

Abstract: A high-temperature thermoelectric module. The module includes a two part molded egg-crate for holding in place and providing insulation and electrical connections for a number of thermoelectric n-legs and p-legs. A first part of the egg-crate is comprised of a ceramic material capable of operation at temperatures in excess of 600° C. and a second part comprised of a thermoplastic material having very low thermal conductivity. In preferred embodiments the high temperature ceramic is zirconia and the thermoplastic material is DuPont Zenite. The thermoelectric legs are also comprised of high-temperature and low-temperature material. In preferred embodiments the high temperature thermoelectric material is lead telluride and the low temperature material is bismuth telluride. In preferred embodiments metal felt spacers are provided in each leg to maintain proper electrical contacts notwithstanding substantial temperature variations. Preferably the module is sealed in an inert gas filled insulating capsule.

Abstract: In order to determine contact erosion of an electromagnetic switching device, a mechanical parameter is measured which characterizes the time course of the relative movement between the contacts, said movement being caused by an actuator. The point in time when the contacts close is determined by evaluating the time course of the relative movement, and the distance traveled by the contacts until said point in time or the distance traveled by the actuator from said point in time until reaching the final position thereof is detected at least indirectly and is compared to a stored reference value.

Abstract: A miniature quantum well thermoelectric device. The device includes a number of quantum well n-legs and a number of quantum well p-legs. Each of the p-legs are alternately electrically connected in series with each of the n-legs at locations that are thermal communication with a cold side and a hot side. The device can be adapted to function as a cooler and it can be adapted to function as an electric power generator. In a preferred embodiment the p-legs and said n-legs are configured generally radially between the hot side and the cold side. In this preferred embodiments each of the n-legs has at least 600 n-type layers with each n-type layer separated from other n-type layers by an insulating layer and each of the p-legs has at least 600 p-type layers with each p-type layer separated from other p-type layers by an insulating layer.

Abstract: The orthogonal frequency division multiplexing (OFDM) method is well-known for transmitting data on electrical power supply lines. According to this method, the items of information to be transmitted are distributed among numerous carriers, and the composite signal of the modulated carrier signals is transmitted in the form of an OFDM block. Standard OFDM methods are, however, highly sensitive to strong periodic pulse jammers. According to the invention, the method is thus devised such that the OFDM blocks to be transmitted have a length of approximately 85% of the interval between two periodic disturbing pulses. The carrier interval accordingly results from the reciprocal duration of the OFDM blocks. The transmitted OFDM blocks are synchronized with pulse-shaped periodic jammers in such a manner that one block at a time is located between two disturbing pulses. The pulse-shaped jammers can be gated at the receiver.

Abstract: An aluminum burning rocket engine lining. The lining material is or includes one or more transition metal carbides of tantalum, niobium or vanadium. Applicants have determined that in aluminum burning rocket engines molten Al2O3 coats the inside surface of the throat of the rocket nozzle protecting certain transition metal carbides from oxidizing reactions at temperatures below a specific temperature that Applicants call the reaction initiated temperature (RIT). Applicants have proven through calculations and tests that a variety of transition metal carbide compositions as good as or better than tungsten as an engine liner material for aluminum burning rocket engines.

Abstract: An underwater torch with a metal infiltrated ceramic electrode for cutting and machining. The electrode has a composition with an empirical formula MB2-z+N, wherein 0<z<0.10 and M is selected from the group consisting of Zr, Hf and Ti, wherein N is selected from a group consisting of Cu, Au and Ag and wherein the MB2-z defines a ceramic structure formed with ceramic and defining a volume with void spaces comprising at least 10 percent of the volume of the matrix structure and the N occupies a portion of the void spaces. A preferred electrode material is ceramic matrix of ZrB2 slightly enriched in Zr that is infiltrated with copper. Preferred methods of making the composition involves at least two step: First, ZrB2 (which preferably is slightly enriched in Zr) is formed into a ceramic matrix having a density of up to 96 percent. Second, the ceramic matrix is heated in a pool of copper at a vacuum and at an infiltration temperature of about 1700 degrees C.

Abstract: A super-lattice thermoelectric device. The device is comprised of p-legs and n-legs, each leg being comprised of a large number of alternating layers of two materials with differing electron band gaps. The n-legs in the device are comprised of alternating layers of silicon and silicon germanium. The p-legs are comprised of alternating layers of B4C and B9C. In preferred embodiments the layers are about 100 angstroms thick. Applicants have fabricated and tested a first Si/SiGe (n-leg) and B4C/B9C (p-leg) quantum well thermocouple. Each leg was only 11 microns thick on a 5 micron Si substrate. Nevertheless, in actual tests operated the couple operated with an amazing efficiency of 14 percent with a Th of 250 degrees C. Thermoelectric modules made according to the present invention are useful for both cooling applications as well as electric power generation. This preferred embodiment is a thermoelectric 10×10 egg crate type module about 6 cm×6 cm×0.

Abstract: A super-lattice thermoelectric device. The device is comprised of p-legs and n-legs, each leg being comprised of a large number of very thin alternating layers of two materials with differing electron band gaps. The n-legs in the device are comprised of alternating layers of Si and SiC. The p-legs are comprised of alternating layers of B4C and B9C. In preferred embodiments the layers are about 100 angstroms thick. Thermoelectric modules made according to the present invention are useful for both cooling applications as well as electric power generation. This preferred embodiment is a thermoelectric 10×10 egg crate type module about 6 cm×6 cm×0.76 cm designed to produce 70 Watts with a temperature difference of 300 degrees C. with a module efficiency of about 30 percent. The module has 98 active thermoelectric legs, with each leg having more than 3 million super-lattice layers.

Abstract: An electromagnetic switching device includes a contact arrangement with three contacts which couple a three-phase load to three phases of a three-phase power supply system, and disconnect the three-phase load from the three phases. Switching erosion takes place on the contacts. An overall erosion is determined for each contact, and is supplied to a drive circuit. The contact arrangement is operated by the drive circuit as a function of the overall erosion such that the overall erosion of the contacts are approximated to one another.

Abstract: The orthogonal frequency division multiplexing (OFDM) method is well-known for transmitting data on electrical power supply lines. According to this method, the items of information to be transmitted are distributed among numerous carriers, and the composite signal of the modulated carrier signals is transmitted in the form of an OFDM block. Standard OFDM methods are, however, highly sensitive to strong periodic pulse jammers. According to the invention, the method is thus devised such that the OFDM blocks to be transmitted have a length of approximately 85% of the interval between two periodic disturbing pulses. The carrier interval accordingly results from the reciprocal duration of the OFDM blocks. The transmitted OFDM blocks are synchronized with pulse-shaped periodic jammers in such a manner that one block at a time is located between two disturbing pulses. The pulse-shaped jammers can be gated at the receiver.

Abstract: A method for identifying a rotation direction of a three-phase network includes the steps of sampling the individual phases at given times and using an evaluation algorithm to evaluate the measured values or interpolated approximate values, or only the mathematical signs of the values, in order to determine the rotation direction. In addition to the basic method for an ideal signal profile, half-wave-rectified signal profiles of individual phase conductors can preferably be evaluated. The method can advantageously be used to detect the rotation direction with a digital overload relay, using a digital signal control and/or signal processing which is already provided in the digital overload relay.

Abstract: To determine the remaining lifetime of contactor contacts, the contact spring action at the clearance gap can be determined as a substitute criterion for contact erosion, and to determine the erosion of the contact points, the change in spring action during the shutdown cycle can be measured and converted to the remaining lifetime, for which purpose, the time of the armature movement from the start of the armature movement to the start of contact opening is measured with the solenoid actuator having an armature with solenoids and associated yoke. The measured values of the time signal tk of contact opening on the load side of the switching device monitored and the time signal tA are determined by voltageless signaling of the start of armature movement. In particular for use in three-phase systems, the switching voltage is measured as a voltage change at an artificial neutral point. In the respective arrangement, a voltageless signal line is provided between the switching device and analyzer unit.

Abstract: A method for determining switchgear-specific data at contacts in switchgear and/or operation-specific data in a network connected to the switchgear includes detecting a so-called contact follow-through travel at a switching path as an equivalent criterion for an erosion of contacts, particularly for contactor contacts. A resilience change during a shutdown cycle is measured, can be used to determine the erosion and can be converted into a remaining contact life for the contacts. Accurate measurement of the armature movement from a start of the armature movement to a start of contact opening is required for that purpose. Switching states of a switching device and of the electrical network are additionally detected from signals for resilience detection. An apparatus for carrying out the method is also provided.

Abstract: It has been suggested that to determine the remaining lifetime of contactor contacts, the contact spring action at the clearance gap can be determined as a substitute criterion for contact erosion, and to determine the erosion of the contact points, the change in spring action during the shutdown cycle can be measured and converted to the remaining lifetime, for which purpose, the time of the armature movement from the start of the armature movement to the start of contact opening is measured with the solenoid actuator having an armature with solenoids and associated yoke. According to the present invention, the measured values of the time signal tk of contact opening on the load side of the switching device monitored and the time signal tA are determined by voltageless signaling of the start of armature movement. In particular for use in three-phase systems, the switching voltage is measured as a voltage change at an artificial neutral point.