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US 6,747,856 B1Granted
Protective device against fault currents
AssigneeSiemens Aktiengesellschaft
InventorsMarkus Huber, Gerald Lehner
Life of this patent
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Abstract
A device is for protecting against fault currents, even with frequencies of fault currents higher than 1 kHz. Additionally, it is for protecting against fires to dependably protect people. The converting core of a total current converter mounted upstream of a triggering arrangement, in a releasing circuit, is designed for detecting fault currents of different types. Further, an RC circuit is mounted parallel to the triggering arrangement, on the input side.
Claims2
A device for protecting against fault currents, comprising:
- a total current converter;
- a triggering arrangement;
- a triggering relay of a triggering circuit, for activating a switching mechanism which switches a conductor network, wherein a converter core of the total current converter for sensing low-frequency and high-frequency fault currents, is formed from at least one of nanocrystalline and amorphous material;
- and
- an RC element, formed by a series arrangement of a resistor and a capacitor and connected in parallel at an input end of the triggering arrangement, wherein the capacitance of the capacitor is dimensioned such that a triggering fault current lies at least up to a fault current frequency of 1 kHz below a predefined limiting curve for ventricular fibrillation in accordance with Rule IEC 479, and wherein a value of the resistor is dimensioned such that, even at fault current frequencies of up to approximately 20 kHz, the triggering fault current lies below a limiting curve which is acceptable for avoiding fires.
2 more elements
Dependencies are inferred from the claim text.