Abstract: The teachings herein include methods for ascertaining a concentration (cA) of potentially infectious aerosol particles in a volume (V), for example in a conference room, methods for ascertaining an inhalation dose (Z), a device (200), a controller, and a display device. To improve the determination of a concentration (cA) of potentially infectious aerosol particles in a volume (V) with emitters (E1, . . . , En), the method may include: recording at least one time course of an acoustic variable (AS) in the volume (V), said variable being associated with one or more of the emitters (E1, . . . , En), ascertaining an emission (Q) of aerosol particles for at least one of the emitters (E1, . . . , En) on the basis of the recorded time course of the acoustic variable (AS) and ascertaining the concentration (cA) on the basis of the at least one emission (Q).

Abstract: Various embodiments of the teachings herein include an apparatus for identifying a smoke event in an electron beam melting installation comprising: a current meter measuring a grounding current; and a processor programmed to identify a smoke event by evaluating the grounding current.

Abstract: Various embodiments of the teachings herein include an apparatus for identifying a smoke event in an electron beam melting installation comprising: a current meter measuring a grounding current; and a processor programmed to identify a smoke event by evaluating the grounding current.

Abstract: A method and device for assessing damage to a rolling bearing caused by bearing currents, in particular high-frequency bearing currents, in an electric machine which is electrically connected to an inverter, in particular to an inverter having a DC voltage link circuit, is described. The rolling bearing has a lubrication gap between an inner bearing ring and a rolling body and between an outer bearing ring and the rolling body. The method includes detecting the energy of an electric discharge event in the lubrication gaps, searching for a coincident event having a frequency above one GHz indicative of a damaging bearing current event, detecting a frequency of occurrence of discharge events, and evaluating the discharge events by correlating the frequency of occurrence and the energy of the discharge events.

Abstract: A force transducer, in particular a load cell, includes a spring body that deforms when loaded with a force or load to be measured. Two support parts, which are separated by a gap, are moved out of a position of rest. A capacitive displacement detector is used to detect the relative movement of the support parts, where the capacitor includes two electrode combs that are each held on one of the support parts and includes a multiplicity of electrode fingers. The electrode combs are configured designed and mounted on the two support parts such that the electrode fingers of the one electrode comb pass into the finger interspaces of the other electrode comb when the spring body is loaded so that the force transducer is resistant to overloading.

Abstract: A sensor device includes an exchangeable module shaped as a substantially annular disk and concentrically mounted at or on a shaft of an electric machine. The exchangeable module includes a detection device for detecting a bearing current of the electric machine and an energy converter device configured to convert mechanical energy of the shaft into electrical energy for transmission to the detection device.

Abstract: A force transducer, in particular a load cell, includes a spring body that deforms when loaded with a force or load to be measured. Two support parts, which are separated by a gap, are moved out of a position of rest. A capacitive displacement detector is used to detect the relative movement of the support parts, where the capacitor includes two electrode combs that are each held on one of the support parts and includes a multiplicity of electrode fingers. The electrode combs are configured designed and mounted on the two support parts such that the electrode fingers of the one electrode comb pass into the finger interspaces of the other electrode comb when the spring body is loaded so that the force transducer is resistant to overloading.

Abstract: The invention inter alia relates to a method for monitoring the bearing current of an electrical machine (10). An electrode (100) arranged at a distance (d) to a shaft and the shaft—due to the gap (S) between the electrode and the shaft—produce a measurement capacitance (C) and an electric shift current (i) which flows through the measurement capacitance when there is a temporal change of the voltage (Ug) applied between the shaft and the housing is measured. A measurement signal (Ms) indicating a bearing current flow is generated when the shift current or a measurement variable produced by the shift current meets a predetermined trigger criterion. Preferably, the electrode has a circular inner contour so that the gap is annular. The annular inner contour results in an error compensation in the case of a balance error of the shaft because the factor dC/dt remains at least substantially constant. Due to the contactless measurement of the shift current, no contact brushes for contacting the shaft are required.

Abstract: A sensor device includes an exchangeable module shaped as a substantially annular disk and concentrically mounted at or on a shaft of an electric machine. The exchangeable module includes a detection device for detecting a bearing current of the electric machine and an energy converter device configured to convert mechanical energy of the shaft into electrical energy for transmission to the detection device.

Abstract: A method and device for assessing damage to a rolling bearing caused by bearing currents, in particular high-frequency bearing currents, in an electric machine which is electrically connected to an inverter, in particular to an inverter having a DC voltage link circuit, is described. The rolling bearing has a lubrication gap between an inner bearing ring and a rolling body and between an outer bearing ring and the rolling body. The method includes detecting the energy of an electric discharge event in the lubrication gaps, searching for a coincident event having a frequency above one GHz indicative of a damaging bearing current event, detecting a frequency of occurrence of discharge events, and evaluating the discharge events by correlating the frequency of occurrence and the energy of the discharge events.

Abstract: The grounding quality of an electric machine should be better monitored. Therefore, an electric machine is proposed, comprising a stator (1), a rotor (2), a shaft (3), to which the rotor (2) is fastened, and a grounding device (5) for grounding the shaft. The electric machine also has a measuring device (6) for measuring a ground current of the grounding device (5) and for providing a corresponding measured value. The electric machine also has a monitoring device (7) for monitoring the grounding function of the grounding device (5) on the basis of the measured value. In this way, the state of a grounding brush in regard to soiling and wear, for example, can be continuously monitored.

Abstract: The invention inter alia relates to a method for monitoring the bearing current of an electrical machine (10). An electrode (100) arranged at a distance (d) to a shaft and the shaft—due to the gap (S) between the electrode and the shaft—produce a measurement capacitance (C) and an electric shift current (i) which flows through the measurement capacitance when there is a temporal change of the voltage (Ug) applied between the shaft and the housing is measured. A measurement signal (Ms) indicating a bearing current flow is generated when the shift current or a measurement variable produced by the shift current meets a predetermined trigger criterion. Preferably, the electrode has a circular inner contour so that the gap is annular. The annular inner contour results in an error compensation in the case of a balance error of the shaft because the factor dC/dt remains at least substantially constant. Due to the contactless measurement of the shift current, no contact brushes for contacting the shaft are required.