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: Electric arc discharges between bearing rings in a roller bearing are analyzed by setting a defined operating state based on rotational speed of the roller bearing, temperature of the roller bearing, an imbalance of the roller bearing causing vibrations, lubricants, axial/radial/tilt loads, tilting of the bearing rings relative to each other, pulse shape and pulse repetition rate of an applied electrical voltage, bearing play, and pre-existing damage to the roller bearing. A pulse-shaped electrical voltage between inner and outer bearing ring generates electric arc discharges, wherein for each electric arc discharge a characteristic value representative of energy, power, voltage and/or current and duration of the electric arc discharge is determined. Only those electric arc discharges are evaluated that have a qualifying value determined in accordance with at least one of the characteristic values greater than a predefined limit value.

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: Electric arc discharges between bearing rings in a roller bearing are analyzed by setting a defined operating state based on rotational speed of the roller bearing, temperature of the roller bearing, an imbalance of the roller bearing causing vibrations, lubricants, axial/radial/tilt loads, tilting of the bearing rings relative to each other, pulse shape and pulse repetition rate of an applied electrical voltage, bearing play, and pre-existing damage to the roller bearing. A pulse-shaped electrical voltage between inner and outer bearing ring generates electric arc discharges, wherein for each electric arc discharge a characteristic value representative of energy, power, voltage and/or current and duration of the electric arc discharge is determined. Only those electric arc discharges are evaluated that have a qualifying value determined in accordance with at least one of the characteristic values greater than a predefined limit value.