Abstract: A switch for a brush wear monitoring recording circuit for monitoring wear of at least one brush, the switch having an open and a closed state, comprises a fixed part including a switch plate having a switch face and a moving part including a capacitive flag disposed on a brush so as to move the capacitive flag corresponding to a brush wear movement in a brush wear direction and a capacitive plate having a capacitive face, wherein the capacitive face and the switch face are disposed parallel to each other and provide capacitance to the switch, and further wherein the capacitive flag is disposed on the brush so as to bring the capacitive face and the switch face in proximity to each other so as to face each other and increase capacitance, thereby changing the switch state.

Abstract: A method for determining a short circuit between at least two stator laminates in an electrical machine having a rotor mounted on a shaft and a stator, includes rotating the rotor on the shaft relative to the stator so to pass a magnetic stator flux, varying over time, through the stator, determining, during the rotation, a measurement variable sensitive to a short-circuit current caused by the magnetic stator flux between the at least two stator laminates, and determining the magnetic stator flux. In addition, a theoretical model is provided describing a relationship between the magnetic stator flux and the measurement value or an auxiliary variable derived from the measurement value, and the measurement variable or the auxiliary variable is compared with the theoretical model. A device for carrying out a method for determining a short circuit is also provided.

Abstract: An apparatus is disclosed for monitoring brushes, such as slipring or commutator brushes, on electrical machines. At least one electronic sensor is configured to be arranged in or on a brush apparatus of an electrical machine such that an electrical supply power can be locally drawn directly from an electromagnetic environment of the brush apparatus. The apparatus can transmit measurement data detected by it by electromagnetic radiation to an indication device.

Abstract: A method and a device for detecting a touching point (i.e. contact point) on a machine having a rotating shaft, in which the touching point (i.e. contact point) on the shaft is determined during operation. This is performed by measuring the grounding state of the shaft by measuring a characteristic (such as a current) of electricity flowing to ground via one or more ground connections provided on the shaft.

Abstract: A method for detecting vibrations of a shaft of an electrical machine includes measuring at least one of a shaft voltage and a shaft current and analyzing the measured at least one of the shaft voltage and the shaft current so as to determine the vibrations. In addition, an apparatus for detecting vibrations of a shaft of an electrical machine includes a first grounding device disposed at a first point on the shaft on a first side of the electrical machine and a second grounding device disposed at a second point of the shaft on a second side of the electrical machine. The second grounding device is configured to measure at least one of a shaft voltage and a shaft current.

Abstract: An apparatus and a method for monitoring and/or analysis of electrical machines during operation, wherein the electrical machine has at least one generator with a shaft and drive means for driving this shaft, wherein the shaft is grounded at the first end of the generator, and wherein a measurement unit for measurement of shaft voltage and/or shaft current as a function of time is provided on the shaft at the second end of the generator. An apparatus such as this allows the combined and simultaneous measurement of various fault states by supplying signals for the shaft voltage and/or the shaft current to an analysis unit, wherein the analysis unit allows combined and simultaneous analysis of at least two potential fault states of the electrical machine. Simultaneous cross-relationships between the individual measurement results of individual fault states may be provided so as to allow a clearer and more reliable diagnosis of critical states, not possible when individual phenomena are considered separately.

Abstract: A method and a device for detecting a touching point (i.e. contact point) on a machine having a rotating shaft, in which the touching point (i.e. contact point) on the shaft is determined during operation. This is performed by measuring the grounding state of the shaft by measuring a characteristic (such as a current) of electricity flowing to ground via one or more ground connections provided on the shaft.

Abstract: An apparatus and a method for monitoring and/or analysis of electrical machines during operation, wherein the electrical machine has at least one generator with a shaft and drive means for driving this shaft, wherein the shaft is grounded at the first end of the generator, and wherein a measurement unit for measurement of shaft voltage and/or shaft current as a function of time is provided on the shaft at the second end of the generator. An apparatus such as this allows the combined and simultaneous measurement of various fault states by supplying signals for the shaft voltage and/or the shaft current to an analysis unit, wherein the analysis unit allows combined and simultaneous analysis of at least two potential fault states of the electrical machine. Simultaneous cross-relationships between the individual measurement results of individual fault states may be provided so as to allow a clearer and more reliable diagnosis of critical states, not possible when individual phenomena are considered separately.

Abstract: A method for detecting vibrations of a shaft of an electrical machine includes measuring at least one of a shaft voltage and a shaft current and analyzing the measured at least one of the shaft voltage and the shaft current so as to determine the vibrations. In addition, an apparatus for detecting vibrations of a shaft of an electrical machine includes a first grounding device disposed at a first point on the shaft on a first side of the electrical machine and a second grounding device disposed at a second point of the shaft on a second side of the electrical machine. The second grounding device is configured to measure at least one of a shaft voltage and a shaft current.

Abstract: A method and apparatus for detection of spark activity in an electrical machine having a shaft, wherein at least one of the shaft voltage and the shaft current is measured and analyzed for components which are characteristic of spark activity. The method uses the shaft voltages and/or shaft currents which are normally generally regarded only as being damaging has been found to be accurate and to be suitable for long-term monitoring of spark activities such as brush sparking, spark erosion, spark flashovers between parts of the shaft bearings and can be implemented physically very easily and in a reliable manner, since the existing grounding devices are used.

Abstract: The present invention relates to a method, an apparatus and a computer program for inspecting laminated iron cores (1) of electrical machines for interlamination shorts, in which the laminated iron core (1) is magnetized by means of an auxiliary winding, and the iron surface is scanned by means of at least one measurement coil arrangement (2) with a downstream measurement device. In this case, unique and quantifiable localization of interlamination shorts is achieved by using both the phase (8) and the amplitude (7) of the electrical signal which is induced in the at least one measurement coil arrangement (2), in combined form.

Abstract: A protective and monitoring apparatus (20, 23) for monitoring and reducing shaft currents and shaft voltages on the generator shaft (19) of a generator (16) which produces electrical power, which protective and monitoring device (20, 23) is connected between a contact apparatus (21, 24), which makes contact with the generator shaft (19), and a grounding connection (22, 25) and comprises a parallel circuit formed by a resistance and a capacitance, with one end of the parallel circuit (26, 27) being connected to the contact apparatus (21, 24) and its other end being connected to the grounding connection (22, 25), said parallel circuit being protected against overvoltages on the generator shaft (19) and means (31) being provided for bridging the parallel circuit (26, 27) when an overvoltage occurs.

Abstract: The present invention relates to a method, an apparatus and a computer program for inspecting laminated iron cores (1) of electrical machines for interlamination shorts, in which the laminated iron core (1) is magnetized by means of an auxiliary winding, and the iron surface is scanned by means of at least one measurement coil arrangement (2) with a downstream measurement device. In this case, unique and quantifiable localization of interlamination shorts is achieved by using both the phase (8) and the amplitude (7) of the electrical signal which is induced in the at least one measurement coil arrangement (2), in combined form.

Abstract: A protective and monitoring apparatus (20, 23) for monitoring and reducing shaft currents and shaft voltages on the generator shaft (19) of a generator (16) which produces electrical power, which protective and monitoring device (20, 23) is connected between a contact apparatus (21, 24), which makes contact with the generator shaft (19), and a grounding connection (22, 25) and comprises a parallel circuit formed by a resistance and a capacitance, with one end of the parallel circuit (26, 27) being connected to the contact apparatus (21, 24) and its other end being connected to the grounding connection (22, 25), said parallel circuit being protected against overvoltages on the generator shaft (19) and means (31) being provided for bridging the parallel circuit (26, 27) when an overvoltage occurs.

Abstract: The reloadable battery is equipped with solar cells on its casing. To reload the batteries one has to expose them just to daylight.

Abstract: A method for measuring rotational speed in which a plurality of signal sources disposed along the periphery of a rotating system is monitored by a sensor, and the signals generated by the sensor are added by a counter to form a speed signal sum N. An associated time reference value A.sub.N is determined for each speed signal sum N, and the speed signal sum N and the time reference value A.sub.N for each signal source are saved in pairs in a storage medium. To determine the rotational speed, the time reference value A.sub.N-M which had been saved exactly one revolution before along with the speed signal sum N-M is then retrieved from the storage medium by a processor, which determines the difference of the time reference values A.sub.N and A.sub.N-M (the revolution time for one revolution of the rotating system), and then determines the reciprocal value of the revolution time, which represents the speed.

Abstract: A semiconductor switch includes a device for measuring the depletion-layer temperature of a semiconductor rectifier (V) which conducts load current. This device consists of a network (N) which electrically simulates the thermal behavior of the semiconductor rectifier (V), a converter element (W) provided between semiconductor rectifier (V) and the network (N) for producing a current (i.sub.v) which is proportional to the power dissipation in the semiconductor rectifier (V), and a comparator (A) which is controlled by the output of the network (N) and acts on the semiconductor rectifier (V). The semiconductor rectifier has a simple construction, is secured against short circuits and overloads and at the same time is also capable of easily controlling capacitive loads. This is achieved so that, on the one hand, the converter element (W) is configured as an ohmic resistor (R.sub.w) and is connected together with a first switch element (S.sub.1) and a capacitor (C.sub.