Abb Technology Ag

Asea Brown Boveri Ag

Asea Brown Boveri Inc.

Abb Management Ag

Robert Schilling

Stefan Schneeberger

Markus Hansli

Markus Gasser

An electronic circuit arrangement is disclosed for converting an input voltage signal having a first voltage level into an output signal having a second voltage level. An input unit is provided for inputting the input voltage signal at the first voltage level, while an output unit is arranged for outputting the output signal at the output of the electronic circuit arrangement. A threshold value comparison unit serves for comparing the first voltage level of the input signal with a switch-on threshold value. The circuit arrangement furthermore contains an input impedance changeover unit for changing over an input impedance of the circuit arrangement from a low value to a high value after a predetermined delay duration after the first voltage level of the input voltage signal exceeded the switch-on threshold value.

Method for determining a switch-on threshold and electronic circuit arrangement for carrying out the method

A device for detecting the short circuiting of the switches of a converter circuit arrangement is disclosed. The device is magnetically coupled to the current limiter coil and comprises a conductor loop which is preferably arranged at the end of the current limiter coil. On short circuiting, a voltage is induced in the conductor loop. This voltage is converted in a detection circuit into a voltage pulse and fed to an evaluation logic circuit. In the evaluation logic circuit, the period of the induced voltage pulse is evaluated and, if appropriate, load-relieval actuation is initiated.

Device for detecting the short circuiting of the switches of a converter

A digital input is disclosed for supplying a digital signal representing the occurrence of a special event, such as a malfunction, to a recording device. The present invention can be advantageously used in a distribution network for electrical energy, in which the special event triggers the actuation of a switch in a switchgear. The digital input has two first current terminals, to which direct current is applied from an external voltage source. Two second current terminals are connected to a sensor element, for example an auxiliary contact of the switchgear, which outputs the digital signal when the special event occurs. An electrical circuit is also connected to the two second current terminals and carries the digital signal to an optocoupler which provides electrical isolation. The digital input furthermore has a device for converting the direct current supplied from outside the device into a direct current which is electrically isolated therefrom. The device is operatively connected to the two first current terminals on the input side and to the signal circuit on the output side. In contrast to digital inputs according to the prior art, only signal currents are supplied via the two second current terminals. For this reason, only very simple protective measures against electrical and electromagnetic noise levels must be taken at the current terminals.

Apparatus for producing a digital input to a recording station

The input and/or output device for process data has a mounting rack (1), as well as a plurality of modules (2) fastened on the mounting rack (1). A process connector (4) can be inserted into each of the modules (2) on the front side in each case. Each module (2) has a circuit board (17) which is arranged in a housing (8), as well as a terminal strip (18) which is connected non-positively to the process connector (4). The terminal strip (18) serves to receive contact pins (26) which interact with contacts of the process connector (4). The input and/or output device is intended to demonstrate a high degree of operational reliability even in the case of a high level of mechanical and electromagnetic stresses. This is achieved in that the module housing (8) is predominantly formed from metal plate and has lugs (21, 22, 23) formed out of the metal plate which serve to carry the circuit board (17), some of which lugs are electroconductively connected to a conductor track (32) of the circuit board (17), and in that the module housing (8) is in contact with a metal part of the mounting rack (1) which is at ground potential.

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Niederrohrdorf, Switzerland

Robert Schilling