Abstract: A method to determine the natural frequencies of a bearing system having a shaft arranged on bearings is disclosed in which the shaft is vibrationally excited from one end of the shaft and a measurement signal is picked up at the other end of the shaft using a vibration sensor.

Abstract: In order to provide a measuring device for electric motors, in particular spindle motors, comprising a motor mount, in which the electric motor to be tested can be positioned on the stator side for the measurement, and a first runout measuring device, which has at least a first runout sensor and with which a runout in a first direction can be sensed on a rotor of the electric motor held in the motor mount, which device allows the most efficient possible measuring of individual parameters of an electric motor, it is proposed to provide a second runout measuring device which has at least a second runout sensor and with which a runout of the rotor in a second direction, extending transversely in relation to the first direction, can be measured at the same time as the runout in the first direction.