Electrical circuit breaker for protecting against overcurrents
AssigneeABB Research Ltd.
InventorRalf Strümpler
Life of this patent
Estimating the term…
Abstract
The invention relates to a combination of a microrelay switch (1) switching off small overcurrents, and a short-circuit current limiter, for example a fuse link, a PTC thermistor 16 or a power breaker, for limiting or switching of large overcurrents.
Claims18
An electrical switching device comprising:
- a microrelay switch which is arranged in a current path and has microrelay cells connected in series as a voltage divider and connected in parallel as a current divider:
- a current sensor which detects a current flowing in the current path;
- an evaluation device for receiving and evaluating current signals detected by the current sensor and for forming a tripping signal, which acts on the microrelay switch, if the current being carried in the current path exceeds a threshold value;
- and
- a short-circuit current limiter arranged in the current path such that the short-circuit current limiter is connected in series with the microrelay switch;
- wherein
- the switching device is designed such that the microrelay switch opens in response to the tripping signal for small overcurrents that are greater than the threshold value, and, in the event of large overcurrents, the short-circuit current limiter limits these overcurrents to currents which can be interrupted by the microrelay switch.
The electrical switching device as claimed claim in 1, wherein the evaluation device is designed for receiving and evaluating signals from a first current sensor, which detects the current through the current path, and from a second current sensor, which detects a current through a second current path, by comparing them with one another and opening the microrelay switch in response to a result of an evaluation.
Dependencies are inferred from the claim text.