Abstract: A device is disclosed which includes a frame (1), a turntable (3), and an electromagnetic drive unit comprising a stator section (5) and a rotor section (7). The turntable, which is rotatable about a shaft (19), and a frame portion (4) have facing annular bearing surfaces (21A and 21B respectively) to form a dynamic axial bearing. The bearing surfaces are coaxial with the shaft and radially spaced from this shaft. One of the bearing surfaces has at least one pattern of grooves which causes a pressure to be built up in a medium present between the bearing surfaces during rotation of the rotor section relative to the stator section.

Abstract: A system is disclosed which comprises an electrical actuator (2), a current source (35), a actuating unit (37) having a limited operating range, and a control unit (41). The actuator comprises a first actuator body having two diametrially opposed magnetic poles, and a soft-magnetic second actuator body, which is coaxial with the first actuator body and which preferably comprises three circumferentially equi-spaced teeth, which each carry an energizing coil (29, 30, 31). The first actuator body and the second actuator body cooperate with one another via an air gap and are pivotable relative to each other through a specific angle about a pivotable axis. The control unit is constructed to divide the operating range of the actuating unit into a plurality of sub-ranges and, depending on said sub-ranges, to controllably feed a current through one of the energizing coils, through two of the energizing coils, and through all the energizing coils, respectively.

Abstract: A hybrid stepping motor comprises a stator with two annular coils, which each cooperate with two sets of stator teeth, and a rotor with two rotor sections which are separated by an axially magnetized magnet. These rotor sections each comprise two sets of rotor teeth which each cooperate with one of said sets of stator teeth. The various tooth offsets in this motor are obtained by providing an offset of 1/2 tooth pitch for each annular coil and by providing an offset of 1/4 tooth pitch between the two rotor sections.

Abstract: Two stator sections are each provided with an annular coil which cooperates with sets of teeth to be magnetized oppositely by the coils. The teeth are arranged in sectors on each section in such a way that the sectors of teeth of one set of teeth lie between those of the other set of teeth. The rotor comprises two rotor sections each having one circularly arranged set of teeth which cooperates with the two sets of teeth of the associated stator section. The two rotor sections are axially spaced by an axially magnetized permanent magnet.