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AssigneeSiemens Aktiengesellschaft
InventorsUlrich Baumgaertl, Manfred Schiller
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In power breakers which have a current transformer (6) with a current detection coil (7) without any iron and have an integration circuit (8) connected downstream from the current detection coil (7), the unavoidable time constant of the integration circuit (8) can lead to spurious trippings. This is avoided by a method in which the instantaneous values of the current are detected and stored at defined periodic intervals (n, n+l, n+2). The stored measured values are compared on the basis of polarity and magnitude. If it is found that the stored values have the same polarity and fall monotonally, it is assumed that the DC element is originating from the integrator (8) and a tripping inhibit signal is set in the electronic release of the power breaker.
A method for operating an electronic overcurrent release (5) for a power breaker, which has a current transformer (6) for supplying the overcurrent release (5) with a signal which is proportional to the current through the power breaker, which current transformer (6) has a current detection coil (7) without iron, and an integration circuit (8) connected downstream from the current detection coil (7), characterized by the following steps
A method for operating an electronic overcurrent release for a power breaker, which has a current transformer for supplying the overcurrent release with a signal which is proportional to the current through the power breaker, which current transformer has a current detection coil without iron, and an integration circuit connected downstream from the current detection coil
Dependencies are inferred from the claim text.