Abstract: In order to implement a secure monitoring function for a long-stator linear motor or planar motor, the invention proposes that at least one first measurement value of a first sensor is compared to a predefined plausibility threshold value, and in the event of said plausibility threshold value being exceeded by the first measurement value, an error is identified and an action is triggered.

Abstract: In order to ensure safe operation of a multi-phase system, even a system including a plurality of phases, a number of phase groups is provided, which comprises some of the phases, wherein phase currents of the number of phase groups are merged in a group node to form a group sum current and a group sum current measurement value of the group sum current is captured. The current measurement values belonging to the number of phase groups are summed up to form a group sum and the group sum is compared with the group sum current measurement value to validate the phase currents of the phases in order to ensure safe operation.

Abstract: To reliably determine a state variable (G) of a polyphase synchronous machine (1) that is supplied with electric current by a polyphase power network (2) with n phases (U, . . . , N), where n?3, the current values of at least n?1 phase currents (Iu, . . . , In-1) from at least n?1 phases (U, . . . , N-1) of the polyphase power network (2) are detected. The state variable (G) is determined by means of the at least n?1 instantaneous current values (Iu, . . . , In-1), the current values of all n phase currents (Iu, . . . , In) from the n-phase polyphase power network (2) being detected and the n phase currents (Iu, . . . , In) being correlated with one another. The result of the correlation of all n phase currents (Iu, . . . , In) is used for a plausibility check of the n?1 phase currents (Iu, . . . , In-1) used to determine the state variable (G).

Abstract: A rolling stand for producing rolled strip, includes rolls which are axially displaceable with respect to one another, and have a curved contour running over the entire effective barrel length and complement one another exclusively in a specific relative axial position of the rolls in the unloaded state. To vary the thickness profile of the roll gap over the active roll barrel length there is axial displacement of the rolls which are provided with a roll barrel contour in relation to one another in such a way that a rolled strip that is planar and free from undulations. The profile of the barrel contour of the rolls of a pair of rolls is formed by a trigonometric function and the roll gap contour is also formed by a trigonometric function in dependence on the profile of the barrel contour and the position of the rolls within the axial displacement region.