Abstract: In order to make the commonly used approximation switch insensitive to intermittently occurring magnetic interference fields, such switch consisting of a magnetic field sensor (1) acting via an amplifier stage (2) on a switching stage (3), provision is made for a second sensor (4) reacting to such interference fields, said sensor, in its activated state, returning the given output signal of the switching stage (3) to the input of the amplifier stage (2) for maintaining the given lead signal of the sensor stage (magnetic field sensor 1), and thus preserving the functional state of the approximation switch present in the event of interference.

Abstract: An inductive proximity switch comprises a high-frequency oscillator, an oscillator coil and an oscillator core. An analyzing circuit detects the inclination amplitude depending on the degree of core saturation. The analyzing circuit triggers a switching process when a certain threshold value of amplitude is reached. The core consists, for example, of ferrite. A yoke-like body is assigned to the core. The use of such a soft-magnetic material for the yoke-like body, allows the construction of smaller sensors with a higher sensitivity and a more cost-advantageous production. Their permeability curve in relation with one quadrant of the coordinate system is clearaly S-shaped.

Abstract: An inductive proximity switch including an oscillator a circuit of which has an oscillator magnetic core adapted to be influenced by a trip device for the purpose of actuating an electronic switch. The proximity switch is adapted to detect an approach of the trip device, of a permeable material, through a nonferromagnetic wall so as to enable a triggering of the switching process. A sensor field formed of a magnetic field of a permanent magnet or an electromagnetic, with the proximity switch having a saturation-sensitive magnetization area or region in which the magnetic fluxes of the permanent magnet or electromagnet and oscillator core heterodyne. The inductive proximity switch is adapted to be operated in saturation by a reduction in a magnetic resistance produced by introducing the permeable trip device into the sensor field, damping the oscillator circuit and causing a switching of the electronic switch.

Abstract: A magnetic-field-dependent inductive proximity switch having a coil arrangement with a ferromagnetic core, which is saturation-sensitive with respect to the magnetic field to be picked up, and having an electronic analyzing circuit for triggering a switching process at a certain core saturation, is to be constructed so that its power requirement is very low, for example, in the range of 0.1 to 5.0 milliampere, and that, by means of said switch, a magnetic field can be picked up through a non-ferromagnetic wall and can be used to trigger switching operations.

Abstract: A status indicating system for the instantaneous registration of the open and closed states of the switches of a remotely supervised high tension plant comprising a multiplicity of substations each having a plurality of high tension switches which require monitoring and supervision, wherein each switch is provided with two pilot indicating contacts signalling the respective switch position of off and on, said pilot indicating contacts delivering signals to a remotely located central supervision station by means of a long distance transmission circuit where the signals are monitored. In the status indicating system every high tension switch is provided with two proximity switches registering its end positions. The proximity switches are damped by a vane which is moved by an operating shaft of the high tension switch. The two possible outputs of activated proximity switches are always different from zero and these outputs actuate pilot indicating contacts by means of pilot relays.