Abstract: In order to determine an operating temperature of an electric motor which is fed via an inverter, the inverter is first of all permanently assigned to an electric motor. Following calibration of measured value of at least one operating parameter of the electric motor by the assigned inverter on the production line of the electric motor and inverter, at least one measured value of at least one operating parameter of the electric motor is then acquired by the assigned inverter during operation of the electric motor and the operating temperature of the electric motor is determined using this at least one measured value and the calibration result from the assigned inverter.

Abstract: A method for operating an electric motor with at least two motor terminals that are driven by a control device contains the steps of short-circuiting of at least two of the motor terminals of the electric motor by the control device; measurement of the motor phase currents at the short-circuited motor terminals; and identification of a standstill of the electric motor if a magnitude and/or a frequency of the motor phase currents measured lies below a predefined limit value. In the case of such a reliable identification of the standstill of the electric motor, an enable signal can then advantageously be generated in order, by way of example, to enable access to an apparatus driven by the electric motor.

Abstract: A method for operating an electric motor with at least two motor terminals that are driven by a control device contains the steps of short-circuiting of at least two of the motor terminals of the electric motor by the control device; measurement of the motor phase currents at the short-circuited motor terminals; and identification of a standstill of the electric motor if a magnitude and/or a frequency of the motor phase currents measured lies below a predefined limit value. In the case of such a reliable identification of the standstill of the electric motor, an enable signal can then advantageously be generated in order, by way of example, to enable access to an apparatus driven by the electric motor.