Abstract: A method and an apparatus are provided for determining the distance of a probe, particularly a magnetic bearing or a magnetic levitation device, from a conductive reaction rail. The probe comprises at least one sensor having at least two magnetically-coupled coils disposed opposite the reaction rail. The coils generate an alternating magnetic field whose influences (eddy currents) are detected by the sensor and employed for identification of the distance. In order to achieve a high, useful voltage level, insensitivity to external electrical fields and potential fluctuations, as well as a small influence of system-conditioned magnetic fields, the influences of eddy currents induced in the reaction rail by the alternating magnetic field are acquired and utilized for the identification of the distance.

Abstract: In magnetic bearings and magnetic suspension devices, sensors (4), as they are used for bearing regulation of support and guide magnets in magnetic transportation technology, continuously measure the distance of a magnet (6) from a reaction rail (7), in order to obtain a signal with which the magnet (6) is controlled with regard to the energizing current in such a way that it remains suspended at the predetermined distance. In known devices, there is no accurate monitoring of the sensor signal, which can result in faulty regulation of the excitation if the sensor signal is faulty, which represents a significant safety risk.

Abstract: For raising and lowering theatre scenery there is a horizontal track in the fly loft of the theatre, and several carriages, slidable along the track, are shiftable to any desired positions along the track, positions being chosen in accordance with possibly uneven or non-uniform weight distribution in the scenery to be handled. A series of cables, one for each carriage, runs from a common winding drum to one end of the track and then to an anchorage at the opposite end of the track. Each cable runs over two pulleys of its own individual carriage, and forms a downwardly extending loop between these two pulleys. A pulley block rides on each loop. All the pulley blocks are ordinarily connected to a scenery batten, from which the scenery is hung, but when specially required, individual pulley blocks may be used separately.