Abstract: A hydraulic drive for a hydraulic consumer alternately pressurized in opposite directions during operation is disclosed.

Abstract: A method for monitoring the operation of a frequency converter (1), which is designed to drive an electric motor (2), wherein the method comprises the following steps: generating phase voltages (u1, u2, u3) for corresponding phase sections (2.1, 2.2, 2.3) of the electric motor (2), ascertaining a voltage rotating field, measuring occurring phase currents (i1, i2, i3), ascertaining a current rotating field depending on the measured phase currents (i1, i2, i3), calculating a phase difference between the voltage rotating field and the current rotating field and/or calculating a frequency difference between the frequency of the voltage rotating field and the frequency of the current rotating field, and determining a fault state when the phase difference exceeds a phase difference threshold value and/or when the frequency difference exceeds a frequency difference threshold value. pa (FIG.